Subtract erase layer geometry from a target layer and download the remaining features.
Use an erase layer to remove overlapping areas from the source layer.
Files are processed in your browser and are not uploaded to servers.
Results are exported as standard GeoJSON FeatureCollections.
Upload the target GeoJSON layer.
Upload the erase GeoJSON layer to subtract.
Difference Analysis subtracts one layer from another: upload a target layer and an erase layer, and everything that overlaps the erase geometry is removed from the target. The output keeps only the parts of your target features that fall outside the erase areas, with attribute fields carried over.
This is the GIS "erase" operation used everywhere: clipping parcels to remove flood-zone areas, cutting exclusion buffers out of a study region, or trimming a licence block where a neighbouring claim overlaps. Both layers are processed locally in your browser, and the difference downloads as GeoJSON.
Upload the target layer you want to keep, then upload the erase layer whose overlapping geometry will be removed — GeoJSON and Shapefile are both supported.
Run the difference analysis; the browser computes, for every target feature, the remaining geometry after subtracting the erase layer.
Review the resulting features and their count in the summary, then download the clipped result as a GeoJSON FeatureCollection.
AThey are completely removed and produce no output geometry. Features partially overlapping are split so that only the portion outside the erase geometry remains, keeping the original attributes.
AThe target (source) layer is the one you want to keep; the erase (overlay) layer defines what gets removed. Swapping the two layers gives the opposite result — the tool is not symmetric, so choose the order according to what you want left over.
AYes, both layers must share the same coordinate reference system, otherwise the subtraction will be geometrically wrong. If they differ, reproject one layer to match the other before running the analysis.
ANo. The output contains the attributes of the target features, because the erase layer only defines the geometry to remove — no fields are transferred from it.