County Maps US

Tools Map makers and file viewers

GeoJSON Viewer

A quick check of a file before it goes into a database or a report. Invalid geometry is reported by feature rather than failing silently.

How to use it

  1. Drop a .geojson or .json file on the box, or choose one.
  2. Read the counts, total line length and extent, then click features on the map or in the list for their properties.
  3. Hide or show points, lines and polygons with the chips.
  4. Convert to KML or GPX if another program needs it.

How it works

The file is parsed as JSON and accepted as a FeatureCollection, a single Feature or a bare geometry. Each geometry is checked for valid nesting and coordinate ranges; a bad feature is listed by name or index and skipped so one typo does not hide the whole file. Coordinates are assumed to be WGS84 longitude and latitude, as the GeoJSON specification requires.

Line lengths are great-circle sums along each line. Files are limited to 8 MB and the feature list shows the first 1,000 features.

Questions

My file loads but everything is in the wrong place or missing.
The coordinates are probably projected (for example UTM or a state plane) rather than longitude and latitude. GeoJSON must be WGS84; reproject the file first.
Does it handle TopoJSON?
No. Convert TopoJSON to GeoJSON first; the topojson-client library or mapshaper can do that.
Is there a size limit?
Yes, 8 MB. Above that, simplify the file or split it. The viewer runs entirely in your browser, so a huge file would only slow your own machine.

All map tools, free and without an account. Location data is processed in your browser and by the open geocoding services named on the sources page; nothing is stored by this site.