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Model parameters
All settings for a run live in cfg/main/ModelParameters.dms. They are also written into the metadata file that accompanies every stored result, together with the GeoDMS version, the machine, the user and the git revision of the configuration, so that a result can always be traced back to the run that produced it.
| Parameter | Default | Meaning |
|---|---|---|
Org_Gridsize, Dest_Gridsize
|
1 | grid size in km for origins and destinations |
MaxTravelTime |
120 min | see the note below |
NumberOfItersForNetworkCleanUp |
10 | iterations of the network compression, see Network construction |
PopVersie |
GHS_WUP_POP_E2025_GLOBE_R2025A_54009_1000_V1_0 |
the population raster to use |
PopGridSize |
1000 | cell size of the population raster in metres |
OSM_file_date |
20260202 | the date stamp of the Geofabrik extracts, which selects the source directory |
OSM_dir_date |
latest |
the date part of the .pbf file names |
Settlements_Set |
SMOD_V1s6_opr_P2023_v1_2020 |
which of the two settlement sets the analyses use |
MaxTravelTime is recorded in the run metadata but does not drive any computation in the current configuration. The cut off values that are actually applied are set where they are used: 120 minutes for the settlement hierarchy matrix, which follows from the largest threshold, and 60 minutes in the Travel distance proxy.
| Parameter | Default | Used |
|---|---|---|
MaxCarSpeed |
130 km/h | metadata only |
MaxCarSpeed_limit |
100 km/h | metadata only |
CarDefaultSpeed |
50 km/h | metadata only |
CarDefaultSpeed_low |
30 km/h | yes |
ConnectorLinkSpeed |
15 km/h | metadata only |
Ferry_Speed |
10 km/h | metadata only |
Only CarDefaultSpeed_low is wired into the computation. It is applied in three places: as the speed of links whose road speed is undefined, including the artificial links that connect origins and destinations to the network; as the speed at which the detour of an unconnected grid cell is priced in Accessibility; and as the speed used to convert the self distance into a self travel time in the Travel distance proxy.
The speeds of ordinary road links do not come from these parameters. They come from the maxspeed tag of the OSM line, or, when there is none, from the road type table in Classifications/OSM/roadtype, which holds a speed inside and outside built-up areas for each of 78 road types. Changing how fast the model drives means editing that table, not these parameters.
ModelParameters/Advanced/OSM_Regios lists the eight Geofabrik regions to read. It is a source data setting rather than a modelling setting, and it should match the files actually present in the OSM directory.
| Placeholder | Meaning |
|---|---|
%SourceDataDir% |
root of the source data on the machine |
%NetworkModelWorld_DataDir% |
%SourceDataDir%/NetworkModel_World, all read only input |
%LocalDataProjDir% |
all intermediate and result files written by the model |
%projDir% |
the repository, used to write the git revision into the metadata |
%NetworkModelWorld_DataDir% is set in ConfigSettings/Overridable in main.dms and can be pointed elsewhere without touching the rest of the configuration.
Some parameters are cheap to change, others invalidate everything downstream.
| Change | Consequence |
|---|---|
| decay function in the travel proxy | rerun the proxy only |
| catchment threshold or minimum population | rerun catchments and functional rural areas |
Settlements_Set |
rerun centroids, hierarchies, catchments, accessibility |
PopVersie or PopGridSize
|
rerun land cells, centroids, networks and all analyses |
OSM_file_date |
rerun the region files and both network steps, then everything |
the country list in set_countries
|
rerun countries, separated units, grids and networks, that is everything |