Compare Map
A Compare Map shows two maps of the same place at once and keeps them locked together, so panning or zooming one moves the other. It answers the question a single map can't: what changed, or how do these two things line up?
Choose between a swipe layout — both maps full-bleed, with a divider you drag across to reveal one under the other — and a split layout that gives each map its own half. Either can be divided left/right or top/bottom.
The two sides are independent in everything but the camera. Each holds its own dataset, its own display mode (raw geometry, heatmap, clusters, or a travel-time area), its own colors, and even its own basemap — so you can put satellite imagery on one side and a street map on the other.
Each side also keeps its own background layers, pulled live from published WMS, ArcGIS, PMTiles or XYZ tile services. That is what makes a genuine before-and-after possible without uploading anything: put last year's imagery behind one half and this year's behind the other, and drag the divider between them.
What you can do
- Swipe divider or split screen
- Each side has its own data and style
- Each side has its own background layers
- Both maps move together
How to create a compare map
- 1
Create a Compare map
Start a new site and choose the Compare map type.
- 2
Import both datasets
Give the Before and After sides a file each — GeoJSON, TopoJSON, KML, KMZ, GPX, a zipped Shapefile, CSV, or Excel.
- 3
Style each side
Pick how each side draws its data, set its colors, and give it a basemap and a label — plus its own background layers from a WMS, ArcGIS, PMTiles or tile service.
- 4
Choose the layout
Swipe or split, divided left/right or top/bottom, and set where the divider starts.
- 5
Publish
Publish to your free subdomain or your own custom domain — visitors get the same draggable comparison.
Compare Map FAQ
Do both sides have to show the same kind of data?
No. Each side is configured on its own, so one can draw raw polygons while the other renders a heatmap or clusters of the same points. One side can even show a travel-time area from a single origin and use no uploaded file at all.
Can each half use a different map style?
Yes. Every side picks its own basemap — any of the built-in styles, one of your saved custom themes, or the site's map style — which is what makes satellite-against-streets comparisons work.
Do the two maps stay in sync?
In the swipe layout, always: the maps overlap, so they have to show the same view. In the split layout it is a setting, so you can unlock the halves and frame each one separately if you would rather compare two different places.
Can I compare two aerial images or published map services?
Yes, and you don't need a file to do it. Each side takes up to 5 background layers from published WMS, ArcGIS, PMTiles or {z}/{x}/{y} tile services, drawn live from the publisher. Give each half a different vintage of imagery — or an official dataset against your own — and drag the divider between them. A side with only background layers and no uploaded data renders perfectly well.
Can a Compare map be connected to Google Sheets?
No. Sheets sync keeps one dataset per map in step with one spreadsheet, and a Compare map holds two, so it is file import only. The same applies to the visitor-facing field search, which indexes a single dataset.