OneTaskBy Tim King · Updated
GeoJSON Editor
View, Draw and Edit GeoJSON on a Map in Your Browser
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How the GeoJSON Editor works
This GeoJSON editor shows features on a map and lets you edit them. Paste GeoJSON into the box or load a file and every feature appears on the map — points as
markers, lines and polygons as shapes, with a popup listing each feature's properties.
Choose a mode to add points, lines or polygons by clicking the map; the text updates as you
draw, and edits to the text redraw the map. Download the result as a .geojson file or
copy it to the clipboard.
GeoJSON editor: features, geometry and properties
GeoJSON is the plain-text format that web maps, GIS tools and most location APIs
exchange: a FeatureCollection of Feature objects, each with a geometry and a bag of
properties. Because it is JSON, it is easy to generate from code and easy to break by
hand — a missing bracket or a swapped coordinate pair is invisible until you see it on a
map. This editor keeps the text and the map side by side so you can do both.
Coordinate order. GeoJSON is longitude first, then latitude, then an optional
elevation: [-0.1281, 51.508] is Trafalgar Square. The most common mistake is pasting
latitude first, which puts London somewhere in the Indian Ocean. The
coordinate picker gives you both orders if you need to
check.
Geometries. Points, LineStrings and Polygons are the three you draw here, plus their Multi variants, which the viewer renders but does not create. A polygon's first ring is the outer boundary and must close on itself — the tool repeats the first vertex for you when you press Finish shape. Additional rings are holes. Polygons are counted in the area figure and lines in the length figure, both on the WGS84 sphere.
Drawing. Switch to Add points and each click adds a Point feature named in order.
Draw line and Draw polygon collect clicks as a red dashed draft; Finish shape turns the
draft into a feature and writes it into the text, and Undo point removes the last vertex,
or the last feature once the draft is empty. Each new feature gets a name property that
you can edit in the text box, along with any other properties you want to add.
Files and size. Load accepts .geojson and .json; download writes pretty-printed
JSON, and Minify strips the whitespace, which typically halves the size for a file that
will be fetched by a web page. To convert GeoJSON to GPX or KML, or the other way, use
the GPX converter. Everything happens in your browser
using OpenStreetMap tiles; the data is never uploaded.
FAQ
Why does my point show up in the sea?
Almost always because the coordinates are latitude first. GeoJSON wants [longitude, latitude], so [51.5, -0.12] lands off the coast of Somalia while [-0.12, 51.5] is
London. Swap the pair and the map corrects itself.
Does it validate the JSON?
It parses it. A missing bracket or trailing comma shows an error and the map keeps the last good state until the text parses again. It does not check the GeoJSON specification beyond that, so an unknown geometry type is ignored rather than flagged.
Can I edit a feature's properties on the map?
No, properties are edited in the text box. Click a feature on the map to see its properties in a popup, find it in the text and change the values there; the map redraws as you type.
How big a file can it handle?
Tens of thousands of features are fine. Beyond that the browser slows down while redrawing on every keystroke, so for a large national dataset use a desktop GIS and keep this for inspecting and touching up smaller files.
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