Rasterization

The rasterization model is a part of the Simulation Core, that is tasked with converting attributes and polygons from features of various layers into raster values.

Layers

The layer rasterization sequence of the polygon features is:

1. Net Lines
2. Addresses
3. Buildings
4. Terrains
5. Areas
6. Neighborhoods

Methods

Converting polygons to grid cells can be done in different ways. A common approach is by checking the intersection between the polygon outline and the cell. As displayed below:

Outline rasterization method

However this will create a small overshoot resulting in larger cell area than the original polygon. To correct for this one could also rasterize based on the center point. As displayed below:

Center rasterization method

While more accurate, this method may fail for objects smaller than the grid cell area. If the cell center point misses a small object, it won't be rasterized and remains as traversable space in the simulation.

To compensate for this situation the default option is combined center + outline. This method uses center-point rasterization for most objects and outline rasterization for small ones to ensure coverage.

Via the editor Calculation panel the rasterization method can be selected.

• Combined Center for large and Outline for small polygons (default).
• Outline Overshoot results in more cells than polygon area.
• Center Fastest but missing small polygons.

Note: Since version 2025 combined is the default, before that outline was used.

Select rasterization method in calculation panel

See also

• Grid Overlay
• Rasterization (Average Overlay)
• Rasterization (Combo Overlay)
• Rasterization (Distance Overlay)
• Rasterization (Sight Distance Overlay)

API Endpoints

• Api session event editor setting set rasterization