DTM Module is a module for generating DEM grids from random point data or contour lines using weighted interpolation methods, this module uses existing points / markers and / or contours as input data, make sure you have 3D points (can be obtained using the Map Coordinates module or Offline GPS module) and / or contour data obtained using the Contour module.
Open the module and click DTM icon (bottom left) or tap anywhere on the maps to show DTM Interpolation options windows as shown below:
Number Of Grid: is the number of grids to be created in both the X and Y directions. Please note that the larger the number of grids to be created will make the interpolation process longer.
X Spacing & Y Spacing: is the spacing between the grids to be created in meters.
Data Source: is a data source that will be used in the DTM interpolation process. Data can be existing points / markers, existing contours or both. All data used must have elevation data.
Data Border: is the boundary area that will be covered by DTM, the choices are current view or data bound (minimum & maximum data).
Search Radius: Is a data search radius that will be used to find points as a source of data for the interpolation process at one DTM node. The optimal search radius will depend on the characteristics of the data distribution and the topographic shape of the area being mapped. The bigger search radius can produce smooth DTM surface but it takes a long interpolation time and reduces the accuracy. You can do some experiments with different search radius to get optimal results for your current data.
Show Contours: is option to show contour line base on number of contour line, custom elevation (premium) or contour interval (premium). This contour is very useful for visually viewing and controlling DTM quality.
Show DTM: option to show / hide DTM points.
After the DTM and Contours are created, you can do editing on it by adding 3D points (premium), the DTM / Contours will be automatically refreshed in realtime.