GIS & Map Data Workbench
Inspect and edit offline map layers from GeoJSON, GPX, KML, coordinate CSV and supported shapefile ZIPs. Measure features, simplify lines and export geographic data or map previews.
Map workspace
Move over the map to inspect longitude and latitude.
Open data or try the example. This view uses no online basemap.
Inspect feature properties
Features in selected layer
| Feature | Geometry | Positions | Length / perimeter | Area |
|---|
Using GIS & Map Data Workbench
Inspect and edit offline map layers from GeoJSON, GPX, KML, coordinate CSV and supported shapefile ZIPs. Measure features, simplify lines and export geographic data or map previews.
- Open geographic files or try the park-and-trail example. Auto assumes WGS84 for GeoJSON/CSV unless a supported embedded CRS is present; shapefile ZIPs need a supported PRJ or an explicit source CRS.
- Toggle layers and colors, select features in the table, review properties and measurements, or draw and move vertices. Pan by dragging the map.
- Review simplification and export the selected layer or visible layers as GeoJSON, GPX, KML or coordinate CSV. Save a project to keep layer styles and edits.
Example
Try the park boundary and walking route. Select the route, edit its properties, switch to Move selected vertices and drag a point. Use undo before comparing measurements.
Questions & answers
Does it need online map tiles?
No. It displays your geometry over an optional graticule without a street or satellite basemap. Import, editing and exports run locally. The page may still load site advertising and optional analytics.
Which coordinate systems are supported?
WGS84 longitude/latitude and EPSG:3857 Web Mercator. Imported Web Mercator coordinates are converted to WGS84 for storage and GeoJSON export. Coordinate CSV exports include both systems. Other projections require conversion in another GIS application first. GPX and KML are treated as WGS84.
Which shapefiles can I open?
A ZIP with exactly one 2D SHP dataset, optional DBF/CPG and a supported PRJ. Point, MultiPoint, PolyLine and Polygon are supported. Z/M, MultiPatch, unsupported projections and unsupported DBF field types are rejected. DBF deleted records are omitted; SHX is not required for sequential reading.
Are measurements and simplification exact?
Distance and area are spherical estimates rather than survey-grade ellipsoidal calculations. Simplification uses Web Mercator distances, which are increasingly distorted near the poles, and does not guarantee polygon topology. Inspect your result and use undo.
Can I edit geometry?
Draw points, lines or polygons. Select a feature and choose Move selected vertices to drag its existing vertices; polygon closure is maintained. Edit properties as a JSON object. This does not provide spatial joins, topology repair, buffering or general reprojection.
What do exports preserve?
GeoJSON preserves supported geometry and properties in WGS84; optional decimal rounding applies to longitude/latitude. KML export carries properties as a JSON description. GPX supports points and lines with names and available elevation, not arbitrary properties or polygons. Coordinate CSV lists vertices and property JSON rather than preserving geometry topology. PNG is only a view image. Shapefile export is not provided.
What about the antimeridian and polar regions?
The view does not wrap geometry across the antimeridian, so crossing datasets may display widely stretched lines. Web Mercator display clamps latitude near 85 degrees. Source WGS84 data retains valid polar coordinates; measurements and display have limitations there.
What limits apply?
16 MiB input, 20 layers, 5,000 total features and 100,000 coordinate positions. A shapefile ZIP supports up to 30 files and 32 MiB expanded. Saved projects support 16 MiB.
How can I keep my work?
Save a project JSON containing the data, layer names, colors and visibility. It reopens without the source files. Files are not automatically persisted by the tool.
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