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The guide shows examples of how to convert a surface model file (LAZ) to a true ortho and a DEM (GeoTIFF) with FME.
The example is in the file Surface ModelLazTillTiffDEMOchTrueOrtho.fmw.
Guide - Convert a Surface Model File to a True Ortho and a DEM
Do this in FME (tested in version 2019.2):
- Add a LAS reader that can load the surface model file and two GeoTIFF printers where the result should end up.
- Add an Image Raster izer-transformer.
- Edit Image Raster izer-transformer parameters as shown below.
- Add a Raster DEMGenerator and edit its parameters according to the example below.
Step 3 - edit the parameters of Image Rasterizer transformers. Click on the image to see it larger. Step 4 - add a RasterDEMGenerator and edit its parameters. Click on the image to see it larger.
Surface tolerance
We have tested with Surface Tolerance = 0. It worked but it took a long time to run the data. The more this figure is raised, the faster it is possible to run data, but at the same time it provides a more generalized height model.
It took an hour and 17 minutes to drive data with Surface Tolerance value 0 on an older laptop:
Click on the image to see it larger.
It took 19 minutes to run data with Surface Tolerance 0.1 on an older laptop:
Click on the image to see it larger. - Tie all the transformers together and run the spinner. For example, it can give this result:
Dem (GeoTIFF):
Example results: DEM (GeoTIFF). Click on the image to see it larger. True ortho:
Example of result: true ortho. Click on the image to see it larger.