3.3.1.4. Land cover distribution grid

Two different land cover grids are considered in AccessMod:

1. The original land cover grid containing the broad land cover types such as forest, build areas, large water bodies, agriculture fields, plains, etc.
2. The final merged land cover grid which is generated using the merge land cover tool of AccessMod (see Section 5.5.2) and that also includes the roads and the barriers to movements (e.g. large rivers, lakes,…).

The original land cover grid holds information on the types of land cover (and their spatial arrangements) that characterize the area of analysis and that are believed to affect the travelling time of patients moving across this area.

This grid must contain integer values, with each value corresponding to one land cover class (land cover IDs). These land cover IDs are then linked to corresponding travel speed through the travelling scenario table (see section 3.3.2.2). Starting with version 5.6.8, AccessMod will automatically convert an imported landcover data set with floating point values into their corresponding integer values. 

To facilitate the integration of the roads and barriers into the final land cover distribution grid, AccessMod offers a module (see section ‎5.5.2) that facilitates this process.

The merged land cover grid is typically constructed only once. Further alternative scenarios of travel (various speeds and/or modes of transportation) can be easily set up using the travelling scenario text file. This being said, it is possible to create different merged land cover layers to simulate the impact of flooding or the construction of a new road.