By calculating a travel time map, each pixel is assigned the time required to reach that pixel from user-specified source pixels, for example time to reach schools, villages etc.
A travel time map can be created in three steps:
- prepare a source map and a weight map. The weight (resistance) factors in the weight map reflect the relative decrease of speed in less accessible terrains compared to the best accessible terrain;
- perform a distance calculation using both maps;
- perform a MapCalc operation to convert the obtained output values from the distance calculation into time units (seconds, minutes, hours, etc.).