Guide
GPX and KML: Edit, Convert, and Plan
GPX and KML are the two open XML formats that hold most GPS data: GPX for devices and apps, KML for earth and map viewers. This guide shows how to open and edit either one, convert between them, measure distances, and export the result to a print-ready PDF or a GeoJSON file. KMZ archives, imagery included, and GeoJSON files open here too, and every tool runs on your device, so nothing is uploaded to a server.
GPX or KML: which to use
Pick the format your destination expects. If you are loading a route onto a GPS device or a fitness app, use GPX. If you are sharing a map with placemarks and styling for an earth or map viewer, use KML. When the two do not match, convert: the file converters below move waypoints, routes, and tracks cleanly between the formats. For a deeper look at the data model, read what is GeoJSON, the open standard most mapping and GIS tools read.
Edit, measure, and export
Four formats come in: GPX and KML up to 5 MB, a KMZ archive up to 25 MB that needs no unzipping and brings its imagery in as an overlay, and GeoJSON up to 5 MB. When the map already holds data, a file can merge into it or replace it.
After importing, you can add and move waypoints, draw or adjust routes, and measure each leg with a running total. When the map is ready, export it as an image, a print-ready PDF at a true cartographic scale, a KMZ that carries your image overlays into Google Earth, or a standard GeoJSON FeatureCollection that opens in common GIS tools. Everything auto-saves in your browser between visits, and a free sign-in lets you keep several route projects as named maps in your account, ready on any device.
Frequently asked questions
What are GPX and KML?
Both are open XML formats for geographic data. GPX is the common format for GPS devices and apps, focused on waypoints, routes, and tracks. KML is used mainly by earth and map viewers and carries richer styling and placemarks. Because both are plain text, they convert cleanly between each other.
How do I edit a GPX or KML file online?
Open the map, choose Import from the File menu, and pick your file. Drag points, draw or adjust routes, add waypoints, then export a clean GPX or KML file. Everything runs in your browser, so the file is never uploaded to a server.
Can I open KMZ and GeoJSON files as well?
Yes. A KMZ is a zipped KML and opens directly, no unzipping, up to 25 MB, with its overlay imagery placed on the map. GeoJSON opens too, up to 5 MB: a file MapGridder exported returns to its own layers, and a file from elsewhere is placed by geometry, with points becoming waypoints and lines becoming routes.
How do I convert GPX to KML or KML to GPX?
Use the dedicated converter: drop in the file, and it produces the other format to download. Waypoints, routes, and tracks carry across between the two formats.
Can I measure distances and export to PDF?
Yes. Measure a route leg by leg with a running total, then export the map (with your track, grid, and annotations) as an image, a print-ready PDF at real scale, or a GeoJSON file.
Are these tools free?
Yes. Editing, converting, and measuring run in your browser with no login or install; a quick, free sign-in is only needed to export a finished map.
Need to put a reference grid over your route? See the map grid references guide.