Data Prep Toolbox

(Geo) DataMerger

Mon, 01 Jan 0001 00:00:00 +0000

geo-data-merger.dataprep.jp

What is this tool?

A web-based tool for easily merging geographic data (GeoJSON/TopoJSON) with attribute data (CSV/JSON). It is a convenient data processing tool for when you want to link thematic data (e.g., population, attribute values) to map data.

Features

Load geographic and attribute data…Read GeoJSON/TopoJSON, CSV, and JSON files, and preview their contents.
Key-based join…Join geographic data (Feature properties) with attribute data using a common key column (left join basis).
Remove unnecessary columns…After merging, select and remove unwanted columns from the output via the UI.
Output format selection…Save and download the merged data as GeoJSON/TopoJSON/CSV.

How to use

1. Load geographic and attribute data…Load GeoJSON/TopoJSON on the left side and CSV/JSON on the right side.
1. Specify the join key…Select the column (key) used for joining from each data preview, and verify that they match correctly.
1. Remove unnecessary columns…Select and delete unneeded attribute columns after merging.
1. Export and save…Export the merged data as GeoJSON/TopoJSON/CSV.

Data formats

Input formats
- GeoJSON: Geographic Features (points/lines/polygons) + attributes.
- TopoJSON: A geographic data format that preserves topology (an extension of GeoJSON).
- CSV/JSON: Thematic data to merge (tabular data containing region codes or key-value pairs).
Output formats
- GeoJSON/TopoJSON: Merged geospatial data.
- CSV: Merged tabular data.

Choosing the Right Data Wrangling Tool

Mon, 01 Jan 0001 00:00:00 +0000

Here is a guide to the data wrangling tools available, organized by purpose.

Visually cleanse your data

dataviz.jp

OpenRefine

Data cleansing and transformation tool for tabular data

open-refine.dataprep.jp

Easily merge map data with thematic data

dataprep.jp

(Geo) DataMerger

Easily merge geographic data with thematic data

geo-data-merger.dataprep.jp

Quickly understand JSON structure

dataprep.jp

JSON Crack

Visually understand JSON data structures in your browser

jsoncrack.dataprep.jp

Fix character encoding issues

dataprep.jp

Shift JIS ⇄ UTF-8 Converter

Convert character encoding between Shift JIS and UTF-8

change-character-encoding.dataprep.jp

Easily convert addresses to latitude/longitude

dataprep.jp

Address to Lat/Lon Converter

Geocoding tool

address-to-latlon.dataprep.jp

Extract table data from PDFs

dataprep.jp

Tabula PDF

Extract table data from PDFs

tabula-pdf.dataprep.jp

Remove furigana from Aozora Bunko texts

dataprep.jp

Aozora Furigana Remover

Remove furigana and metadata from Aozora Bunko novels

aozora-furigana.dataprep.jp

Use Mapbox Studio base maps in Foursquare Studio or Kepler.gl

dataprep.jp

Mapbox Classic Styles

Mapbox map tiles for use with Kepler.gl and Foursquare Studio

classic-mapbox-styles.dataprep.jp

Reduce map data file size

dataprep.jp

Mapshaper

Process and convert map data

mapshaper.dataprep.jp

Quickly create buffer zones around POIs

dataprep.jp

Turf Buffer

Easily create radius buffers in your browser

turf-buffer.dataprep.jp

Create custom map data

dataprep.jp

GeoJSON.io

Trace map tiles to create GeoJSON

geojson.dataprep.jp

Format and convert map data

dataprep.jp

Lat/Lon Formatter

Easily convert latitude/longitude decimal places

latlon-formatter.dataprep.jp

dataprep.jp

Transform Coordinates

Convert coordinates of geographic feature files

transform-coordinates.dataprep.jp

Convert bus route data to network data

dataprep.jp

GTFS to Network

Convert GTFS transit data to network data

gtfs-to-network.dataprep.jp

Convert SVG for use in graphic tools

dataprep.jp

SVG ⇄ GeoJSON Converter

Convert between GeoJSON and SVG formats

geojson-and-svg.dataprep.jp

GeoJSON.io

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

GeoJSON.io

地図タイルをトレースしてGeoJSON作成

geojson.dataprep.jp

What is this tool?

A simple browser-based tool for creating, viewing, and sharing spatial data (such as GeoJSON). You can draw and edit geographic data on a map, and the corresponding GeoJSON is generated instantly, making it ideal for prototyping and verifying spatial data.

Features

Draw and edit data on a map…Draw markers (points), polylines (lines), and polygons (areas) on the map and freely edit them.
Real-time code editing and preview…Drawn shapes are instantly updated and displayed as GeoJSON code, and attribute editing is also supported.
Multi-format import…Import and edit spatial data including GeoJSON, TopoJSON, CSV, KML, and more (historically supported by the tool).
Simple attribute editing…Edit and delete field values in table view to adjust Feature properties.

How to use

Load data or create new drawings…Upload existing GeoJSON, or draw points, lines, and polygons on the map.
Edit attributes and code…Interactively edit drawings and attribute information.
Save and share…Download the completed GeoJSON as a file or share via URL parameters.

Data formats

Input formats
- GeoJSON: A JSON format centered on geographic Features (points, lines, areas).
- TopoJSON / CSV / KML / GPX, etc.: Multiple geographic data formats can be loaded and converted to GeoJSON for editing.
Output formats
- GeoJSON, TopoJSON, CSV, KML, WKT, Shapefile

GTFSネットワークデータ変換

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

GTFSネットワークデータ変換

交通データGTFSをネットワーク・データに変換します

gtfs-to-network.dataprep.jp

What is this tool?

Converts GTFS data, a common format for transit information, into network data.

Features

Uses stop information (stops.txt) and stop time information (stop_times.txt) to generate network data in CSV format.

1. stops.txt (used as node information)

Variable	Description	Required	Usage
`stop_id`	Stop ID	Yes	Used as node ID (source/target).
`stop_name`	Stop name	Yes	Node name attribute. Also assigned as origin/destination names for links.
`stop_lat`	Latitude	Yes	Node coordinates.
`stop_lon`	Longitude	Yes	Node coordinates.

2. stop_times.txt (used for link aggregation)

Variable	Description	Required	Usage
`trip_id`	Trip ID	Yes	Used for grouping to identify movements (A to B) within the same trip.
`stop_id`	Stop ID	Yes	Identifies the source and target of each link.
`stop_sequence`	Stop sequence	Yes	Determines travel order within a trip (used for sorting).
`arrival_time`	Arrival time	Yes	Calculates link travel time (next stop arrival - current stop departure).
`departure_time`	Departure time	Yes	Calculates link travel time.

Output data attributes (aggregated/calculated values)

CSV Header	Description	Calculation Method
`frequency`	Number of trips	Count of `trip_id`s traversing the same segment (source to target).
`avg_duration_sec`	Average travel time (seconds)	Average travel time for the same segment.

How to use

1. Upload GTFS files…Load the target files via drag-and-drop or file selection.
1. Specify the current format…Select whether it is 1 file or 2 files.
1. Press the convert button…
1. After conversion, the file is automatically downloaded.

Data formats

Input formats
- GTFS: Stop information (stops.txt)
- GTFS: Stop time information (stop_times.txt)
Output formats
- CSV (single-file format): Nodes and links combined in a single file
- CSV (two-file format): Nodes and links in separate files

Japanese-Western Calendar Converter

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Japanese-Western Calendar Converter

Convert between Japanese era dates and Western dates

calendar-converter.dataprep.jp

What is this tool?

A browser-based tool for converting between Japanese era dates (Showa, Heisei, Reiwa) and Western calendar dates. You can type a date and see the conversion in real time, or drop a CSV file to auto-detect date columns and batch-convert them for download. All processing runs entirely in your browser — no data is ever sent to a server.

Features

Real-time conversion — Type in either the Japanese era or Western date field, and the other field updates instantly
CSV batch conversion — Drag & drop a CSV file to auto-detect date columns and batch-convert them. Preview the results before downloading
Auto character encoding detection — Automatically detects UTF-8 and Shift_JIS, so CSV files created in Excel can be loaded as-is
Multiple date formats supported — Accepts commonly used formats such as R6.3.22, 令和6年3月22日, 2024/03/22, 2024-03-22, and more
Output format options — When converting to Japanese era dates, choose between alphabetic notation (R6.3.22) or kanji notation (令和6年3月22日)
Bilingual UI — The interface displays in Japanese or English based on your browser’s language setting

How to use

Manual conversion

Enter a date in either the “Japanese era” or “Western” input field at the top of the page
The converted result appears automatically in the other field

Batch file conversion

Drag & drop a CSV file onto the drop area (or click to select a file)
Date columns are auto-detected and a before/after preview is displayed
Select the conversion direction (Japanese era → Western / Western → Japanese era) and format as needed
Click “Convert and Download” to download the converted CSV

Data formats

Supported input formats

Type	Example formats
Japanese era (alphabetic)	`S49.9.24`, `H1-1-8`, `R6/3/22`
Japanese era (kanji)	`昭和49年9月24日`, `令和元年5月1日`
Western	`2024/03/22`, `2024-03-22`, `2024.3.22`

Supported eras

Era	Abbreviation	Period
Showa (昭和)	S	1926/12/25 – 1989/01/07
Heisei (平成)	H	1989/01/08 – 2019/04/30
Reiwa (令和)	R	2019/05/01 –

Batch file conversion

Supported file formats: CSV, TSV, TXT
Delimiters (comma, tab) are auto-detected
Character encoding (UTF-8, Shift_JIS) is auto-detected
Output is UTF-8 (with BOM) CSV, which opens directly in Excel

JSON Crack

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

JSON Crack

ブラウザ上で JSON データ構造を視覚的に理解する

jsoncrack.dataprep.jp

What is this tool?

JSON Crack is a web-based data visualization tool. It is designed to help you visually understand JSON data structures in your browser.

Features

Visualizes JSON and structured data as node-and-edge graphs or trees, with expand and collapse capabilities.

How to use

1. Input data…Paste JSON or upload from a file.
1. An interactive node diagram or tree is rendered based on the input content.
1. Expand/collapse, search, zoom, and other operations as needed.

Data formats

JSON

Mapbox Classic スタイル生成

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Mapbox Classic スタイル生成

Kepler.gl や Foursquare Studio で利用可能な Mapbox 地図タイル

classic-mapbox-styles.dataprep.jp

What is this tool?

A web tool for generating and managing style definitions (JSON) for legacy Mapbox Classic styles. Mapbox Classic was a set of classic map style templates provided by Mapbox, used to generate and serve map styles compatible with map tools such as Kepler.gl and Foursquare Studio.

Features

Mapbox Classic style generation…Generate and reference Classic style JSON files (e.g., Streets, Light, Dark, etc.).
Compatible with Kepler.gl and similar tools…Use the generated styles as base maps in map visualization tools like Kepler.gl.
Template management…Organizes Mapbox Classic standard templates for easy access, with features to retrieve and edit JSON as needed.

How to use

Obtain a Mapbox token
Enter your Mapbox token
Select a style template…Choose a Classic style (e.g., Light / Dark / Streets, etc.).
Generate JSON…Generate the Mapbox Classic style JSON based on your selection and edits.
Import…Import the generated style JSON into Mapbox Studio.
Base maps created in Mapbox Studio can be used in Kepler.gl and Foursquare Studio.

Data formats

Mapbox token

Mapshaper

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Mapshaper

mapshaper.dataprep.jp

What is this tool?

A web-based tool for editing, converting, and simplifying geospatial vector data (GIS). It loads map data and lets you intuitively perform operations such as shape simplification, attribute editing, and format conversion. Its key advantage is the ability to process data in the browser without relying on desktop GIS software.

Features

Load and display geographic data: Import and display vector data such as Shapefile, GeoJSON, and TopoJSON.
Shape simplification: Reduce polygon/line vertices to shrink file size while preserving topology.
Attribute data editing: Modify and join attribute table contents, or delete unnecessary fields.
Conversion and export: Convert and export to multiple formats (Shapefile, GeoJSON, TopoJSON, CSV, TSV, SVG, etc.).
Clipping and dissolving: GIS processing such as clipping, merging, splitting, and dropping data.

How to use

1. Load and display data…Imported geographic data is displayed in map view, where you can review attributes and shapes.
1. Edit and process
- Simplification: Run tools for vertex reduction and topology preservation.
- Attribute editing: Add, delete, or join fields.
- Merge and clip: Merge multiple datasets or clip to a specified area.
1. Export…Save and download in the desired format from the Export menu.

Data formats

Mapshaper handles the following major GIS vector data formats for input and output:
Shapefile (ESRI’s standard GIS format; a set of .shp/.dbf/.shx files, etc.)
GeoJSON (JSON-based geographic information format)
TopoJSON (topology-compressed format based on GeoJSON)
CSV / TSV (as tabular data containing coordinates and attributes)
SVG (as vector image output for geographic shapes)

OpenRefine

Mon, 01 Jan 0001 00:00:00 +0000

dataviz.jp

OpenRefine

表データのクレンジング・ツール

open-refine.dataprep.jp

What is this tool?

OpenRefine is a tool for cleaning (deduplication, inconsistency correction, formatting) and transforming tabular data in the browser. It can process large volumes of data in batch, significantly reducing the need for manual corrections.

It can save the state of your cleansing work on the server side, and also record cleansing procedures for reapplication to similar files.

Features

Filtering and faceting for narrowing down and reviewing values
Column splitting/merging, value replacement, whitespace and symbol normalization
Duplicate detection and clustering for inconsistency correction
Batch transformation using expressions (GREL)
Reconciliation with external data sources

How to use

1. Load data in CSV / TSV / Excel / JSON or other formats
1. Use Facets and filters to identify problematic values
1. Clean up data using transformations, replacements, and clustering
1. Export in the desired format

Data formats

Input: CSV, TSV, Excel (xls/xlsx), Google Sheets, JSON, XML, OpenDocument, etc.
Output: CSV, TSV, Excel, JSON, etc.

Official documentation site

dataviz.jp

OpenRefineの公式解説サイト

OpenRefine解説

open-refine-doc.dataviz.jp

Shift JIS ⇄ UTF-8 文字コード変換ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Shift JIS ⇄ UTF-8 文字コード変換ツール

文字コードを、Shift JIS ⇄ UTF-8 間で相互に変換

change-character-encoding.dataprep.jp

What is this tool?

A tool that converts text file character encodings between Shift JIS and UTF-8 in both directions.

Files intended for use with Excel are often distributed in Shift JIS encoding.
Most modern tools assume UTF-8 encoding.

This is a simple utility to bridge that gap.

Features

Shift JIS to UTF-8 conversion: Converts text in the Shift JIS character encoding, commonly used by legacy systems and Excel, to UTF-8.
UTF-8 to Shift JIS conversion: Converts text in UTF-8 format to Shift JIS, making it usable with legacy software and older systems.

How to use

1. Enter or upload the text you want to convert.
1. Copy or download the converted text.

The tool automatically detects whether the file is Shift JIS or UTF-8.

Data formats

Tabular data (CSV, TSV, DSV)
JSON

SVG ⇄ GeoJSON 変換ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

SVG ⇄ GeoJSON 変換ツール

GeoJSON と SVG の相互変換を支援

geojson-and-svg.dataprep.jp

What is this tool?

A web-based tool that assists with converting and visualizing between geospatial data (GeoJSON) and SVG (vector image format).

It is designed to convert geographic information such as map data and polygons into the SVG format, which is convenient for web display and print use, or to help work with SVG as GeoJSON format.

GeoJSON is a standard JSON-based format for location data, widely used for web mapping and GIS integration.

Features

Bi-directional conversion between geospatial data (GeoJSON) and SVG (vector image format)

How to use

1. Load a file
1. Download

No special operations are required.

Data formats

SVG
GeoJSON

Tabula PDF

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Tabula PDF

PDFから表データを取り出す

tabula-pdf.dataprep.jp

What is this tool?

Tabula PDF is a tool for extracting tables from PDFs and converting them into reusable formats. It is useful when you want to use tables from PDFs published as government documents, survey reports, handouts, and similar materials as data.

You can specify the area of the table to extract on the page, and export it as CSV / JSON / Excel format. It helps you create a starting point for data processing in situations where “you have the PDF but not the original data.”

Features

Table extraction from PDF (page-by-page and multi-page support)
Manual selection of table regions (drag) with extraction preview
Switching extraction modes (rule-based / whitespace-based)
Batch output of multiple tables
Download in CSV / JSON / Excel formats

How to use

1. Upload a PDF file
1. Open the target page and select the table area to extract
1. Choose the extraction mode and review the preview
1. If everything looks correct, export as CSV / JSON / Excel

Data formats

Input: PDF
Output: CSV, JSON, Excel

Notes

This tool is intended for use with PDFs that contain text data.
For PDFs consisting primarily of scanned images, running OCR beforehand will improve extraction accuracy.

Text Entity Extraction Tool

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

Text Entity Extraction Tool

text-entity.dataprep.jp

What is this tool?

A browser-based tool that uses regular expressions to batch-extract hashtags, mentions, URLs, email addresses, and phone numbers from text in CSV/TSV tabular data. All data is processed in your browser and never sent to a server.

Features

5 entity types: Hashtags (#), mentions (@), URLs, email addresses, phone numbers
CSV/TSV support: Load data via file upload or paste into the text area
Column selection: Choose the target column with sample values displayed
Preview: Review loaded data before extraction
CSV export: Download results as CSV with extracted columns appended to the original data (UTF-8 with BOM)
Japanese/English support: Auto-switches based on browser language; manual switching also available

How to use

Input data — Drag & drop a CSV file, or paste CSV/TSV data into the text area
Preview — Check the number of columns and rows (first 100 rows displayed)
Configure & extract — Select the target column and entity type (hashtag / mention / URL / email / phone number), then click “Extract”
Review & download — Check the extraction count and click “Download CSV” to save the results

Data format

Input: CSV (comma-separated), TSV (tab-separated), TXT
Header: Option to treat the first row as column names (if no header, columns are auto-named “Column 1, Column 2, …”)
Output: CSV (UTF-8 with BOM) containing all original columns plus an appended extraction result column. Multiple entities in a single cell are joined with commas

Visually cleanse your data

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when you want to clean inconsistent labels, blanks, duplicate rows, or unnecessary columns in CSV or Excel data while visually checking the result.

Solution

Choose a tool that lets you inspect value distributions, filter problem rows, and apply replacements step by step. If you also want to reuse the same preparation flow on other files, a tool with saved transformation history is a strong fit.

Tool

dataprep.jp

OpenRefine

Data cleansing and transformation tool for tabular data

open-refine.dataprep.jp

Good fit for

Cleaning public datasets
Preparing files before record matching
Reducing manual find-and-replace work

バッファ生成ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

バッファ生成ツール

turf-buffer.dataprep.jp

What is this tool?

A web-based spatial analysis tool that generates “buffers (buffer zones)” at a specified distance around geospatial data (points, lines, polygons).

A buffer is a polygon area that expands a specified distance around a given feature, and is a technique commonly used in GIS spatial analysis.

When creating data maps with buffers such as “within a 10-minute walk from a certain point,” using the desktop application QGIS requires the following steps:

1. Convert the data file from a geographic coordinate system to a projected coordinate system that varies by region
1. Perform the buffering operation
1. Convert back to the geographic coordinate system for output

This tool eliminates this complex workflow, enabling completion in just a few clicks within the browser.

Features

Buffer generation Creates a buffer zone at a specified distance (radius) around the input points, lines, or polygons.
Map preview View the loaded data and generated buffer areas on a web map.
Output format Download buffer results as GeoJSON or SVG.

How to use

1. Upload CSV data…Select a CSV file containing latitude and longitude columns.
1. Specify buffer parameters…Enter the buffer radius (in meters).
1. Generate and review the buffer…Press the create button, and the buffer areas are drawn on the map.
1. Download…Download the results in GeoJSON or SVG format.

Data formats

Input formats
- CSV (tabular data containing latitude and longitude) is loaded for processing.
Output formats
- GeoJSON: Retrieve the generated buffer areas in GeoJSON format.
- SVG: Download as an SVG vector image.

住所 → 緯度経度変換ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

住所 → 緯度経度変換ツール

address-to-latlon.dataprep.jp

What is this tool?

A web-based tool that converts Japanese address data into latitude and longitude (coordinates) through geocoding. It can batch-convert multiple addresses into GPS coordinates for use in map creation and location analysis.

Features

Batch conversion (CSV support)…Upload a CSV file containing multiple addresses, and retrieve latitude and longitude for each address.
High-accuracy geocoding…Uses Geolonia’s community geocoder (based on the Ministry of Land, Infrastructure, Transport and Tourism’s Address Reference Information), achieving conversion accuracy specialized for Japanese addresses.
Character encoding support…You can specify the character encoding of the input file (UTF-8 / Shift_JIS).
Browser-only processing…Data is processed entirely within the browser and is never sent to a server (privacy protection).

How to use

1. Upload a CSV file…Load address data by clicking or drag-and-dropping a CSV file.
1. Specify the character encoding…Select the appropriate encoding from UTF-8 / Shift_JIS.
1. Run the conversion…A CSV file with automatically added latitude and longitude columns is generated.
1. Download / Use…Download the output CSV and import it into map rendering or analysis tools.

Data formats

Tabular data (CSV)

座標系変換ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

座標系変換ツール

地物ファイルの座標を変換

transform-coordinates.dataprep.jp

緯度経度フォーマッター

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

緯度経度フォーマッター

緯度経度データの桁数を簡単に変換

latlon-formatter.dataprep.jp

What is this tool?

A web tool for easily converting the format of latitude and longitude data within CSV files. It is useful when you need to organize and standardize coordinate notation formats when working with geographic data.

Features

Format conversion
Bi-directional conversion between single-column format (latitude and longitude in one cell, e.g., “35.6762,139.6503”) and two-column format (separate latitude and longitude columns).
Auto-detection Automatically detects latitude and longitude columns in the input CSV.
Data preview View the CSV before and after conversion on the spot.
Decimal precision adjustment Adjust the number of decimal places for latitude and longitude values.
Download Download the converted CSV as a file.
Browser-only processing All processing is completed within the browser with no server communication required.

How to use

1. Upload a CSV…Load the target CSV via drag-and-drop or file selection.
1. Specify the current format…Select whether latitude and longitude are in single-column or two-column format.
1. Choose the output format…Select the desired single-column or two-column format.
1. Adjust precision (optional)…Set the number of decimal places for latitude and longitude.
1. Convert and download…After running the conversion, review the preview and download the CSV.

Data formats

Input formats
- CSV: Tabular data with latitude and longitude in either single-column or two-column notation.
Output formats
- CSV (single-column format): Latitude and longitude combined in a single field as “latitude,longitude”.
- CSV (two-column format): Standard format with separate latitude and longitude columns.

青空文庫ルビ削除ツール

Mon, 01 Jan 0001 00:00:00 +0000

dataprep.jp

青空文庫ルビ削除ツール

青空文庫の小説からルビとメタデータを削除

aozora-furigana.dataprep.jp

Easily merge map data with thematic data

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when you have geographic boundaries in one file and statistics in CSV or Excel, and want to combine them quickly for mapping.

Solution

First align a shared key such as municipality code or place name. Then use a tool that accepts both geographic data and tabular data and lets you inspect the join result before exporting.

Tool

dataprep.jp

(Geo) DataMerger

Easily merge geographic data with thematic data

geo-data-merger.dataprep.jp

Good fit for

Mapping statistics by municipality
Testing multiple boundary datasets
Checking join errors before visualization

Quickly understand JSON structure

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when an API response or configuration JSON is complex and you need to quickly see where the fields you need actually live.

Solution

Instead of reading raw text, visualize the JSON as connected nodes. That makes parent-child relationships and nested arrays much easier to understand before you extract or transform anything.

Tool

dataprep.jp

JSON Crack

Visually understand JSON data structures in your browser

jsoncrack.dataprep.jp

Good fit for

Inspecting API responses
Understanding third-party data structures
Preparing JSON for tabular conversion

Fix character encoding issues

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when Japanese text becomes garbled after opening a CSV, or when a GIS or spreadsheet app fails to read the file correctly.

Solution

Identify the original encoding first, then convert the file into the encoding expected by the next tool. A fast converter makes it easy to validate both directions before sharing or importing the data.

Tool

dataprep.jp

Shift JIS ⇄ UTF-8 Converter

Convert character encoding between Shift JIS and UTF-8

change-character-encoding.dataprep.jp

Good fit for

Preparing CSV files for distribution
Fixing import errors in Japanese datasets
Moving files between different systems

Easily convert addresses to latitude/longitude

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when you have addresses for stores or facilities, but need latitude and longitude before you can map or analyze them.

Solution

Convert addresses into coordinate columns first, then move on to visualization or spatial analysis. Batch geocoding is much more reliable and efficient than checking each point manually.

Tool

dataprep.jp

Address to Lat/Lon Converter

Geocoding tool for converting address lists into coordinates

address-to-latlon.dataprep.jp

Good fit for

Mapping store or facility locations
Running spatial analysis on address-based data
Avoiding manual coordinate lookup

Extract table data from PDFs

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when a report or government document includes tables in PDF form and you want to extract them without manual re-entry.

Solution

Select the tabular region first, then extract it while preserving rows and columns. Once the table is out, you can clean headers and blanks in a separate step.

Tool

dataprep.jp

Tabula PDF

Extract table data from PDFs

tabula-pdf.dataprep.jp

Good fit for

Reusing tables from public documents
Extracting figures from survey reports
Reducing manual data entry

Reduce map data file size

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when your map data is too heavy to load comfortably in the browser, share with others, or import into a visualization tool.

Solution

Simplify geometry while preserving shape, and remove attributes you do not need. A tool that also handles conversion and merging helps keep the whole preprocessing flow in one place.

Tool

dataprep.jp

Mapshaper

Process and convert map data

mapshaper.dataprep.jp

Good fit for

Making GeoJSON faster to render
Preparing smaller map files for sharing
Cleaning attributes while simplifying geometry

Format and convert map data

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when decimal precision or coordinate reference systems are inconsistent and your map data does not line up correctly in the next tool.

Solution

Standardize latitude/longitude formatting first, then convert the coordinate system if needed. Splitting the work into formatting and projection changes makes it easier to isolate the source of location errors.

Tools

dataprep.jp

Lat/Lon Formatter

Standardize latitude/longitude format and precision

latlon-formatter.dataprep.jp

dataprep.jp

Transform Coordinates

Convert the coordinate system of geographic files

transform-coordinates.dataprep.jp

Good fit for

Mixing map data from different coordinate systems
Normalizing latitude/longitude precision
Troubleshooting positional offsets

Create custom map data

Mon, 01 Jan 0001 00:00:00 +0000

Use this pattern when the points, lines, or polygons you need are not available as ready-made data and you have to create them yourself.

Solution

Use a tool that lets you draw points, lines, and polygons directly on top of a base map and export GeoJSON. Start with the minimum area or features you need, then add attributes afterward.

Tool

dataprep.jp

GeoJSON.io

Create GeoJSON while tracing over map tiles

geojson.dataprep.jp

Good fit for

Creating a small custom map dataset
Drawing survey points or movement paths
Building GeoJSON without a full GIS workflow

Changelog

Tue, 10 Mar 2026 00:00:00 +0000

Roadmap

We will continue expanding the range of OpenRefine-compatible data preparation methods.

Changelog

May 4, 2026

We are temporarily suspending new paid service applications. We plan to resume within a few days after relaunching the service as separate offerings for data visualization and data processing. Thank you for your patience.

April 21, 2026

Separated the authentication and account dashboard domains.

Sign-up and login have moved to https://id.dataviz.jp/.
Your account dashboard (data library, projects, account settings) remains at https://app.dataviz.jp/.

You will be redirected automatically, but please update your bookmarks.

April 16, 2026

Added new tool: “Bar Chart Cross-Filter.” Upload CSV or TSV data and click across multiple bar charts to cross-filter and explore your data — a BI-style capability now available as a standalone tool.

April 12, 2026

Localized checkout and sign-up flows for English users. The entire subscription experience — from pricing to payment — is now available in English.
Introduced USD pricing for international users. Plans now start at $17/month for individuals and $72/month for small teams.
Renamed “Enterprise Plan” to “Group Plan” for consistency across billing and pricing pages.

April 9, 2026

Launched multi-user plans for teams and departments. Choose from plans for 5, 10, or 30 members.

April 8, 2026

Fixed a display issue around the common header that occurred in some tools.

April 5, 2026

Added new tool: “Japanese-Western Calendar Converter”

April 3, 2026

Launched the “Data Library” page. Accessible from the navigation bar, it lets you browse and search sample datasets available across tools, then launch a compatible tool with the selected data.
Added a “Sample Data” button to each tool’s toolbar. You can now browse and load compatible sample datasets directly from within the tool.

April 2, 2026

The account dashboard domain has been changed from auth.dataviz.jp to app.dataviz.jp. You will be redirected automatically, but please update your bookmarks.
The tools listing page has been moved from the public site https://www.dataviz.jp/ to the members-only page https://app.dataviz.jp/.

March 31, 2026

Added a corporate number database that can be called from OpenRefine’s “Reconciliation” feature

March 24, 2026

Added new tool: “Draw-to-Answer Line Chart”

March 23, 2026

Added new tool: “3D Surface Chart”
Added public sharing feature to Parallel Coordinates

March 18, 2026

Added CSV format and Shift JIS data file support for Gephi and Cytoscape
Added a spiral chart example using RawGraphs to the showcase

March 17, 2026

Added Shift JIS data file support for RawGraphs, Parallel Coordinates, Voyager, Word Cloud, and Data Illustrator

March 14, 2026

Added new tool: “Parallel Coordinates”

March 12, 2026

Removed unnecessary line breaks within cells in Tabula
Added new tool: “Text Entity Extraction Tool”

March 11, 2026

The service was officially launched.

Privacy Policy

Tue, 10 Mar 2026 00:00:00 +0000

Version 1 - Enacted: March 10, 2026

“Data Toolbox” (hereinafter referred to as “the Service”) considers the protection of users’ personal information to be an important responsibility, and hereby establishes the following Privacy Policy.

This Policy describes how personal information is handled within the Service.

1. Information We Collect

The Service may collect the following information.

Data That Users Visualize and Analyze

The Service provides tools primarily intended for data visualization and analysis.

Basic Operation Data uploaded or entered by users (file contents such as CSV, Excel, JSON, manually entered data, etc.) is processed on the client side (within the user’s browser) for most features. This data is not sent to or stored on the Service’s servers.
When the Save Feature Is Used In certain visualization tools, only when the user explicitly selects “Save”, the following data is stored on the server:
- Chart and configuration data that the user has instructed to save
- Data processing via OpenRefine (temporary storage to prevent loss of work data)
Saved data is handled as follows:
- It is linked to the user’s account and accessible only by the user.
- Purpose of storage: Re-display, editing, and sharing (when permitted by the user) of saved content
- Retention period: Until the user deletes it (or all data is deleted upon account deletion)
- Upon request for deletion, data will be promptly removed.
Note Regarding Data Containing Personal Information The Service does not review or screen the content of data entered or uploaded by users in advance. If you upload data containing personal information to the server using the save feature, please handle it under your own responsibility. Unless you use the save feature, no data, including any personal information, will remain on the server.

Unless the save feature is used, no data that has been entered or uploaded (including data containing personal information) will remain on the server. However, OpenRefine performs temporary storage to prevent loss of work state.

Retention Period

Data stored on the server using the save feature (charts, settings, source data, etc.) is retained until the user instructs its deletion.
If an account deletion request is made, all associated saved data will be completely deleted without delay (typically within 7 days).

Information Provided by Users

Name
Email address
Account information
Inquiry details

Information Collected During Service Use

Service usage history
IP address
Browser information
Information obtained through cookies and similar technologies

The Service uses the external payment service Stripe, Inc. for processing payments for paid services.

Credit card information entered by users is sent directly to Stripe’s system and is not stored on the Service’s servers.

The payment-related information that the Service may obtain is limited to non-sensitive information such as the following:

Payment status
Card brand
Last 4 digits of the card number
Payment date and time
Subscription status

2. Purpose of Use of Personal Information

The information collected is used for the following purposes:

Provision and operation of the Service
Management of user accounts
Improvement and development of the Service
Responding to inquiries
Prevention of unauthorized use
Addressing violations of the Terms of Service
Payment processing and contract management for paid services
Notification of important announcements

3. Provision of Personal Information to Third Parties

The Service will not provide users’ personal information to third parties except in the following cases:

When the user has given consent
When required by law
When necessary for the protection of life, body, or property
When requested by a public authority

4. Use of External Services

The Service may use the following external services for its operation.

Stripe (Payment Processing)

Payment processing for paid services is handled by Stripe, Inc. Credit card information entered by users is securely processed by Stripe, and the Service does not obtain or store sensitive information such as card numbers. For information on how Stripe handles personal information, please refer to the following:

https://stripe.com/jp/privacy

5. Cookies and Analytics

The Service may use cookies and similar technologies for the purpose of improving the Service and analyzing usage patterns. Cookies are small pieces of data stored in the user’s browser and do not contain information that directly identifies an individual. Users may refuse cookies through their browser settings; however, doing so may result in some features of the Service becoming unavailable.

6. Security of Personal Information

The Service implements reasonable security measures to prevent leakage, loss, and alteration of personal information. Regarding credit card information, the Service is designed not to retain card information on its side by using a PCI-DSS compliant payment service (Stripe).

7. Disclosure, Correction, and Deletion of Personal Information

Users may request the disclosure, correction, or deletion of their personal information.

If you wish to make such a request, please contact us at the address provided below. After verifying your identity, we will respond within a reasonable scope.

8. Use by Minors

If a minor wishes to use the Service, please obtain the consent of a parent or guardian before doing so.

9. Changes to the Privacy Policy

The contents of this Policy may be changed as necessary.

In the event of significant changes, users will be notified through the Service.

10. Contact Us

For inquiries regarding this Privacy Policy, please contact us at the following:

Data Toolbox Operator: Yuichi Yazaki

Google Forms

Pre-Contract Inquiry about 'Data Toolbox'

forms.gle

Version 1 - Enacted: March 5, 2026

FAQ

Sat, 07 Mar 2026 00:00:00 +0000

About This Service

What is Data Prep Toolbox?

It is a browser-based service for data preparation and preprocessing, including character encoding conversion, PDF table extraction, GeoJSON processing, coordinate transformation, and other tasks before analysis or visualization.

Who is this service for?

This service is for anyone who works with data.

People who want to streamline data formatting and cleansing
People who want to fix character encoding issues
People who need to prepare PDFs, JSON, or geospatial data
People who want preprocessing workflows without writing Python or other code
People working in marketing, government, research, data journalism, and related fields

What kinds of data wrangling can I do?

Visually cleanse data
Easily merge map data with thematic data
Quickly understand JSON structure
Fix character encoding issues
Easily convert addresses to latitude/longitude
Extract table data from PDFs
Quickly create buffer zones around POIs

and more.

See the Choosing the Right Data Wrangling Tool page for details.

Who owns the copyright of outputs created with these tools?

The rights to processed data and outputs belong to you. You are free to publish and use them as you wish.

Can I use outputs created with these tools commercially?

Yes. You can freely use them in reports, presentations, papers, books, websites, and more.

Can I save my work?

Tools that support saving can store your work as a project. For tools without saving support, download the processed output and use it as needed.

What is a project?

We call the combination of “your data” and “your work in a tool” a “project.”

Can I start using it right away?

We are currently building and testing the service. We plan to launch around March 2026.

How to Use

Do I need to install anything?

No installation is required. All tools run in your browser. You don’t need any special software — just an internet connection and a web browser.

Do I need programming skills?

No programming is required. You can create charts and process data simply by uploading or entering your data. We’ve designed professional tools to be as simple to use as possible.

What data formats are supported?

Most tools accept data in CSV format. Some tools also support specific formats such as GeoJSON. Each tool’s page lists supported data formats and provides sample data.

Since Excel files can contain various data structures, we don’t support direct Excel uploads. Instead, we provide the versatile data cleansing tool OpenRefine.

Is sample data available?

We offer two types of data portals: sample data bundled with each tool, and original datasets curated based on popular requests.

Pricing & Subscriptions

How much does it cost?

The most basic Standard Plan is $20/month. Annual billing ($200/year) saves you $40 compared to monthly.

See the Pricing page for details.

Are subscriptions auto-renewed?

Yes. Using Stripe’s subscription system, your subscription is automatically renewed one month or one year after your payment date, depending on your plan.

Can I cancel at any time?

Yes, you can cancel at any time. After cancellation, automatic payments will stop, and you can continue using the service until the end of your current billing period.

Data Security

Can I use personal or confidential data?

Data used in our tools is generally not stored on our servers, but processing methods vary by tool. Some data visualization tools have a feature to save your work-in-progress, and in those cases data is stored on the server. For all other tools, data is not retained on the server side.

Future Plans

Will more tools be added?

We continuously add and improve tools in this service. We plan to add new data visualization and data wrangling tools on an ongoing basis. Some tools may be modified or discontinued. We welcome requests for tools and datasets, and will accommodate them as much as possible.

Adoption & Organizational Use

Can teams or companies use this?

Yes, teams and companies can use this service. As a suite of tools for streamlining data visualization and data wrangling, it can be used by people in various roles such as analysts and planners. It can also be adopted as a common data tool within a team.

However, a license is required for each user. We offer bulk account registration and volume discounts — please contact us via the Contact page.

Can it be used for corporate training or educational purposes?

Yes, it can be used for educational purposes. It can serve as a tool for learning data visualization and data literacy in university courses or corporate training. Since many of the tools are single-function, they are well-suited as teaching materials for understanding data structures and visualization mechanisms.

However, a license is required for each user. We offer bulk account registration and volume discounts — please contact us via the Contact page.

License

Wed, 04 Mar 2026 00:00:00 +0000

A list of licenses and credits for the tools provided by this service.

Open Source Software

The following tools are based on original open source projects. We are grateful to the developers of each project.

Color Brewer — Apache-2.0 License (Cynthia Brewer, Mark Harrower, The Pennsylvania State University)
Cytoscape — MIT License (Cytoscape Consortium)
D3.js — ISC License (Mike Bostock)
Data Illustrator — MIT License (Georgia Tech)
(Geo) Data Merger — MIT License (Fabio Berta)
GeoJSON.io — ISC License (Mapbox)
Gephi Lite — GPL-3.0 License (Gephi / OuestWare)
iwanthue — MIT License (Sciences Po médialab)
JSON Crack — Apache-2.0 License (Aykut Saraç)
kepler.gl — MIT License (Urban Computing Foundation)
Leonardo — Apache-2.0 License (Adobe)
Mapshaper — Mozilla Public License 2.0 (Matthew Bloch)
OpenRefine — BSD-3-Clause License (OpenRefine contributors)
Parallel Coordinates — BSD-3-Clause License (Kai Chang)
RAWGraphs — Apache-2.0 License (DensityDesign Lab, Politecnico di Milano)
Sankeymatic — ISC License (Steve Bogart)
Tabula PDF — MIT License (Manuel Aristarán, Mike Tigas, Jeremy B. Merrill)
Tilegrams — ISC License (Pitch Interactive)
Vega Editor — BSD-3-Clause License (UW Interactive Data Lab)
Voyager 2 — BSD-3-Clause License (UW Interactive Data Lab)
Easings Cheat Sheet — GPL-3.0 License (Andrey Sitnik, Ivan Solovev)

dataviz.jp Original Tools

The following tools are originally developed by dataviz.jp.

ADS-B / AIS Visualization
Aozora Bunko Ruby Remover
Address to Lat/Lon Converter
Buffer Generator
Cartogram Japan
Cartogram Prefectures
Choropleth Japan
Choropleth Prefectures
Coordinate System Converter
GTFS Network Data Converter
Lat/Lon Formatter
Mapbox Classic Style Generator
QuickChart UI
Shift JIS / UTF-8 Encoding Converter
SVG / GeoJSON Converter
SVG Gradient Editor
SVG Texture Editor
Word Cloud

Site

Built with Hugo.
Theme Stack designed by Jimmy.

Specified Commercial Transaction Act

Mon, 02 Mar 2026 00:00:00 +0000

Business Operator

Notation LLC

Business Location

N&E BLD. 7F, 1-12-4 Ginza, Chuo-ku, Tokyo 104-0061, Japan

Contact

info@notation.co.jp

Pricing

All prices are displayed inclusive of consumption tax.

Payment Method

We use Stripe for payment processing.

Handling of Personal Information

Please refer to our Privacy Policy.

Cancellations

No returns, refunds, or cancellations are accepted at the customer’s convenience. Please be aware of this before purchasing.

Supported Browsers

Latest versions of Chrome, Firefox, Safari, and Edge on desktop computers. Tablets and smartphones are not guaranteed to be supported.

Delivery of Products

Upon purchasing paid content, access will be available immediately after the payment process is completed.

Terms of Service

Mon, 02 Mar 2026 00:00:00 +0000

Version 1 - Enacted: March 10, 2026

These Terms of Service (hereinafter referred to as “these Terms”) set forth the conditions for using the data visualization and data processing tool suite service “Data Toolbox” (https://www.dataviz.jp/) (hereinafter referred to as “the Service”) provided by Notation LLC (hereinafter referred to as “the Company”). Users shall use the Service upon agreeing to these Terms.

Article 1: Scope of Application

These Terms apply to all aspects of the relationship between users and the Company regarding the use of the Service.
Any individual rules or guidelines posted by the Company within the Service shall constitute a part of these Terms.

Article 2: Definitions

The terms used in these Terms are defined as follows:

“User” An individual or legal entity who uses the Service upon agreeing to these Terms.
“Account” The identification information assigned to a user in order to use the Service.
“Content” All information provided through the Service, including software, tools, programs, text, images, data, UI, and any other materials.

Article 3: Service Description

The Service is an online service that provides various tools for data visualization and data processing.
The Service includes multiple tools, but the features and content of each tool are subject to change.
The Company may add, modify, or remove features of the Service.
The Company may impose reasonable limitations on usage volume, processing frequency, data size, access frequency, and other usage methods in order to ensure the stable provision of the Service.
The Company may add, modify, or discontinue any tools, features, or content included in the Service.

Article 4: Account Registration

Users may be required to register an account in order to use the Service.
Users shall keep their registration information accurate and up to date.
Users shall manage their account information at their own responsibility.
The Company shall not be liable for any damages arising from unauthorized use of an account.

Article 5: Subscription

Part or all of the Service may be provided in a paid subscription format.
Subscriptions will automatically renew unless cancelled by the user.
Usage fees, payment methods, renewal cycles, and other details shall be in accordance with the information displayed on the Service.
Payments may be processed through third-party payment services such as Stripe.
Users shall also comply with the terms of service of the payment service.
The Company may change the features, content, usage fees, or pricing structure of the Service. Such changes will be communicated by posting on the Service or by other means the Company deems appropriate.

Article 6: Cancellation

Users may cancel their subscription through the prescribed method.
Once the cancellation procedure is completed, no charges will be incurred from the next renewal date onward.
Fees already paid will not be refunded, except as required by law or as otherwise determined by the Company.

Article 7: Handling of Data

Users shall be responsible for the content, legality, and right to use any data entered or uploaded to the Service (hereinafter referred to as “User Data”).
The Company has no obligation to monitor or guarantee the content of User Data.
When handling personal information or confidential information, users shall manage it appropriately at their own responsibility.
Even if User Data is stored or retained within the Service, the Company does not guarantee its storage, integrity, or continued retention. Users shall back up their data at their own responsibility as needed.

Article 8: Visualization and Analysis Results

Visualization results, analysis results, processed data, and other outputs generated by the Service are provided as reference information.
The Company does not guarantee the accuracy, completeness, or usefulness of such results.
Users shall use the results at their own responsibility.

Article 9: Prohibited Activities

Users shall not engage in the following activities when using the Service:

Activities that violate laws, regulations, or public order and morals
Activities that infringe upon the rights of the Company or third parties
Activities that interfere with the operation of the Service
Unauthorized access or attempts thereof
Using bots, scraping tools, automation tools, or similar means to extract content from the Service
Copying, reverse-engineering, or redistributing the software or features of the Service
Using the Service for the purpose of developing a competing service
Developing or providing a service that competes with the Company by utilizing the features of the Service
Any other activities deemed inappropriate by the Company

Article 10: Intellectual Property Rights

Intellectual property rights related to the software, tools, designs, text, images, UI, programs, and other elements of the Service belong to the Company or their rightful owners.
The copyright of visualizations, images, charts, processed data, and other outputs created by users using the Service (hereinafter referred to as “Generated Content”) belongs to the respective user, provided that such use does not infringe upon the rights of the Company or third parties, including software, templates, and design elements included in the Service.
Users may use, publish, and distribute Generated Content at their own responsibility.
Users hereby grant the Company a free-of-charge license to store, copy, process, display, distribute, embed, and otherwise handle Generated Content to the extent necessary for the provision and operation of the Service.
The Company may introduce Generated Content created by users for the purpose of promoting or publicizing the Service, provided that such use does not unreasonably harm the rights of the user.

Article 11: Third-Party Software

The Service may include open-source software or third-party software. The use of such software may be subject to their respective license terms.

Article 12: Changes and Suspension of Service

The Company may change, add, or remove the content of the Service without prior notice.
The Company may suspend all or part of the Service in the following cases:

System maintenance
Incident response
Force majeure
Other cases deemed necessary for operational purposes

Article 13: Suspension of Use

The Company may suspend or delete a user’s account without prior notice if the Company determines that the user falls under any of the following:

Violation of these Terms
Unauthorized use
Extended period of non-use
Other cases deemed inappropriate by the Company

Article 14: Disclaimer

The Company shall not be liable for any damages caused by system failures, data loss, service interruptions, or similar events in the course of providing the Service.
Even if the Company is found to be liable, such liability shall be limited to the total amount of usage fees paid by the user to the Company.

Article 15: Changes to the Terms

The Company may change these Terms when deemed necessary. The revised Terms shall take effect upon being posted on the Service.

Article 16: Governing Law and Jurisdiction

These Terms shall be governed by the laws of Japan.
In the event of any dispute arising in connection with the Service, the court having jurisdiction over the location of the Company’s head office shall have exclusive agreed jurisdiction as the court of first instance.

End of Terms

About Us

Mon, 23 Feb 2026 00:00:00 +0000

Operating Company

Notation LLC

Based on the belief that “data visualization is the intersection of expressive communication and problem-solving,” we provide new forms of notation to the world.

notation.co.jp

合同会社ノーテーション

notation.co.jp

About the Representative

Yuichi Yazaki

After seven years of experience as a user interface designer and art director at Business Architects Inc., Yuichi Yazaki went independent. He is engaged in a wide range of activities related to the practice and promotion of data visualization, including lectures at corporations and educational institutions, information dissemination through the website Visualizing.JP, and community activities through Data Visualization Japan.

He is the sole author of “The Complete Guide to Data Visualization Fundamentals” and co-author of “The RESAS Textbook” (Nikkei BP, 2016). He holds a Master’s degree in Design Science from Chiba Institute of Technology. He is the founder of Data Visualization Japan and a Yahoo! News Expert.

dataviz.jp

データ可視化の基本が全部わかる本

all-about-book.visualizing.jp

Contact

Mon, 23 Feb 2026 00:00:00 +0000

Pre-Contract Inquiries

For inquiries before signing up, please use the form below.

Google Forms

Pre-Contract Inquiry about “Data Toolbox”

forms.gle

Post-Contract Inquiries

After logging in, please contact us through the “Account Information” page accessible from your dashboard.

Pricing Plans

Mon, 23 Feb 2026 00:00:00 +0000

Search

Mon, 01 Jan 0001 00:00:00 +0000

Tools

Mon, 01 Jan 0001 00:00:00 +0000