20 MB GeoJSON sample

A GeoJSON file of exactly 20,971,520 bytes. It is a valid GeoJSON file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 20 MB sample, test or dummy GeoJSON file.

sample-geojson-20mb.geojson

20 MB20,971,520 bytes

Download 20 MB GeoJSON

Created in your browser in a few seconds, then checked against the SHA-256 checksum. The file is not uploaded anywhere. No sign-up.

Type: application/geo+json
SHA-256: 2c23214c610133e8ae607fed1d07b663923891aca808ed17ad8b992472ed1e55
Delivery: Created in your browser from static generator assets (how it works).

What is in this file

A FeatureCollection of 110,727 features: 99,656 points and 11,072 line strings with longitude-latitude coordinates (WGS 84) and properties. A "padding" member, which GeoJSON readers ignore, brings the file to the exact size.

Features	110,727
Geometry types	Point, LineString
Coordinate reference	WGS 84 (RFC 7946)
Encoding	UTF-8 (ASCII characters only)

How the file begins

The opening lines of sample-geojson-20mb.geojson, exactly as they appear in the file.

00000000  7b 0a 20 20 22 74 79 70  65 22 3a 20 22 46 65 61 |{.  "type": "Fea|
00000010  74 75 72 65 43 6f 6c 6c  65 63 74 69 6f 6e 22 2c |tureCollection",|
00000020  0a 20 20 22 6e 61 6d 65  22 3a 20 22 53 61 6d 70 |.  "name": "Samp|
00000030  6c 65 20 47 65 6f 4a 53  4f 4e 20 66 69 6c 65 20 |le GeoJSON file |

Preview

Creates the file in your browser and shows the first 64 KB of it.

Where 20 MB matters

A 20,971,520-byte file: right at the default attachment limit of Outlook, and just under the 25 MB ceilings of Gmail and GitHub web uploads. These are the default limits a file of this size is useful for testing:

System	Limit	Note
Microsoft Outlook	20 MB of attachments by default for internet mail accounts	This file is right at the limit; add a second attachment and it is exceeded.
Gmail	25 MB per message	Under the limit, although email encoding adds about a third in transit.
GitHub web uploads	25 MiB per file added through the browser	Accepted. Pushing with Git allows larger files.
Cloudflare Pages assets	25 MiB per file	The largest round size that can be served as a static asset.
Amazon API Gateway	10 MB payload	Rejected; the upload has to go directly to object storage.
ASP.NET Core (Kestrel)	About 28.6 MB request body by default	Accepted with room for the multipart overhead.

All 20 MB sample files

Use this file for

Finding the first upload limit in a new stack
Load-testing map rendering with many features
Testing map layers and spatial queries

Testing notes for GeoJSON

Swapped latitude and longitude put points in the wrong hemisphere or the ocean. Test with locations you can recognise.
Polygon rings must be closed, with the first and last positions identical.

GeoJSON format reference

Technical details

File name	sample-geojson-20mb.geojson
Format	GeoJSON (GeoJSON)
Extension	.geojson
MIME type	application/geo+json
Size	20,971,520 bytes (20 MB)
Kind	Text
SHA-256	2c23214c610133e8ae607fed1d07b663923891aca808ed17ad8b992472ed1e55
Created	2026-10-23
Validation	See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility.
Preview	Available on this page
Source	Generated in your browser by this site's generator; not copied from elsewhere
Licence	Free to use, modify and redistribute (terms)
Category	GIS

Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked

Verify your copy

This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.

sha256sum sample-geojson-20mb.geojson     # Linux
shasum -a 256 sample-geojson-20mb.geojson # macOS

On Windows, run Get-FileHash sample-geojson-20mb.geojson -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.

Related files

Questions about this file

Is this file exactly 20 MB?: Yes. It is 20,971,520 bytes, which is 20 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
What is inside the 20 MB GeoJSON file?: A FeatureCollection of 110,727 features: 99,656 points and 11,072 line strings with longitude-latitude coordinates (WGS 84) and properties. A "padding" member, which GeoJSON readers ignore, brings the file to the exact size.
Where are the sample features located?: Near sixteen real cities on six continents, with small random offsets, so the result is easy to check on a map.

Download