Add an Area Boundary

Do you want to clearly show which area, city, or region your map covers? You can do that with an area boundary. Follow these steps.

Step 1: OpenStreetMap

OpenStreetMap (OSM) is a global open map database used by Wolf Maps for interactive maps. In OSM, you can find the Relation code for your area.

1. Go to OpenStreetMap and search for your area (for example: Arnhem).
2. Copy the highlighted Relation code. You need this code for the next step in Overpass Turbo.

Step 2: Overpass Turbo

Overpass Turbo lets you filter OSM data and download it as a file you can upload to Wolf Maps.

1. Go to Overpass Turbo.
2. Replace the existing code in the left code field with the code below, and fill in your Relation code.

[out:json][timeout:25];
(
  relation(PASTE_RELATION_CODE_HERE);
);
out body;
>;
out skel qt;

3. Click Run (or Uitvoeren) in the top-left corner.
4. Click Export -> GeoJSON and save the file.

Step 3: Wolf Maps

Now you have a GeoJSON for your region, area, or city and you are ready to add it to your map in Wolf Maps.

1. Open Wolf Maps Studio and choose your map.
2. Go to Settings -> Map -> Boundary.
3. Upload the GeoJSON file and click Save.

Your map now shows the area boundary, so visitors immediately see which region it covers.

Bonus: merge areas

Sometimes you want to combine two or more areas into one shape. For example, when multiple municipalities collaborate. Note: for this workflow you need a ChatGPT Plus subscription.

1. First create separate GeoJSON files for the official regions (as described above).
2. Open ChatGPT and paste all GeoJSON files in one message.
3. Use this prompt to merge them into one area:

Combine these GeoJSON polygons into one single GeoJSON file. Merge overlapping or adjacent areas into one shape, without internal lines. The result must be a valid `Polygon` or `MultiPolygon` containing only the outer boundary.

4. Download the merged GeoJSON and upload it to your Wolf Maps map.