Back to Guides

How to perform an intersection

Share this page

The intersection operation allows you to find overlapping areas between two polygon layers. This is useful for analyzing relationships between geographic features, such as buildings within flood zones, land use inside administrative boundaries, or protected areas affected by urban expansion.

In Atlas, performing an intersection is simple and does not require GIS expertise. Follow the steps below to run your own analysis.


Step 1: Log In and Create a Project

  1. Log in to Atlas: Open your web browser and log in to Atlas.
  2. Create a New Project: Click New Project to start your map.
  3. Name Your Project: Give it a clear title, such as "Buildings in Flood Zones".

Step 2: Add Data

To perform an intersection, you need two polygon layers that will be analyzed for overlap.

Option 1: Upload Your Own Data

  1. Click Add Data in the top-left corner.
  2. Upload your layers in GeoJSON, Shapefile, or CSV format.
    • Example datasets:
      • Buildings layer (polygon).
      • Flood zone layer (polygon).

Option 2: Import Data from OpenStreetMap or Overture Maps

Instead of uploading files, you can bring in public datasets directly from Atlas:

  1. Open the Right-Side Panel.
  2. Under "Import Data From", select OpenStreetMap or Overture Maps.
  3. Choose a dataset:
    • Buildings (from OpenStreetMap).
    • Administrative boundaries or land use zones (from Overture Maps).
  4. Click Import to add the layer to your project.

Step 3: Perform the Intersection

  1. Open the Vector Operations Panel

    • In the right-side toolbar, click Vector Operations.
  2. Select the Intersection Tool

    • Click Intersection from the available operations.
  3. Choose Switch to Datasets

    • Dataset 1: Select the buildings layer (polygon).
    • Dataset 2: Select the flood zones layer (polygon).
  4. Run the Analysis

    • Click Run to create a new layer containing only the overlapping areas.

Step 4: Style and View the Results

  1. Select the New Intersection Layer

    • Find it in the Layers Panel.
  2. Style the Layer

    • Open Standard Styling and adjust the appearance:
      • Fill Color: Choose a distinct color.
      • Opacity: Adjust transparency if needed.
      • Outline: Add a thin border to highlight intersected areas.
  3. Adjust Layer Order

    • Ensure the intersection layer appears above the input layers for better visibility.

Step 5: Share or Export Your Analysis

  1. Export Your Map

    • Click Export to download your map as a PDF or PNG file.
  2. Share Your Map

    • Generate a shareable link to send to others.
    • Share directly with your workspace for team collaboration.
    • Add collaborators to give editing or viewing access.
    • Embed the map on a website or another page for easy access.

Practical Applications of Intersection Analysis

  • Urban Planning: Find buildings inside hazard zones.
  • Environmental Studies: Analyze land use inside protected areas.
  • Infrastructure Development: Identify roads crossing different administrative regions.

Tips for a Smooth Intersection Analysis

  • Use Public Data When Possible: OpenStreetMap and Overture Maps provide ready-to-use datasets.
  • Ensure Both Layers Are Polygons: Intersection currently works with polygon layers in Atlas.
  • Simplify Large Layers: If a dataset has too many features, filter it before running the analysis.
  • Test Different Scenarios: Try intersecting different datasets to gain more insights.

Performing an intersection in Atlas is quick and intuitive. Upload your data, run the tool, and gain valuable insights from spatial overlaps.

Start your intersection analysis in Atlas today!