- Start up FME Workbench and create an blank workspace. Choose Source Data | Add Source Dataset.
The Add Source Dataset dialog box appears.
- Choose ASPRS Lidar Data Exchange Format (LAS) in the Format drop down list. In the Dataset field, click the Browse button and select a LAS file e.g. 288_4320.LAS. Click OK.
The Select Feature Types dialog box appears.
- Toggle off header and variable_length_header (optional). Click OK.
The source dataset is added to the workbench.
- Select Destination Data | Add Dataset.
The Add Destination Dataset dialog box appears.
- In the Format drop down list, choose ESRI ASCII Grid. In the Dataset field, click Browse and choose an output folder e.g. C:\data. Click OK to close the Add Destination Dataset dialog box.
A message appears to confirm the addition of a new feature type.
- Click Yes and OK to add a new Feature Type to the workbench.
The destination dataset is added to the workbench.
- Drag and drop the RasterDEMGenerator transformer and connect the source and destination datasets with the transformer as shown below.
- Open up the RasterDEMGenerator Parameters. In the Output DEM X Cell Spacing and Output DEM Y Cell Spacing fields, type in a cell spacing value e.g. 1 as shown below. Click OK.
- Run the translation.
The ESRI ASCII ArcGrid DEM file is generated and can be displayed in a terrain model viewer.
Wednesday, March 10, 2010
Create a digital elevation model (DEM) from a LAS file with FME
I am quite impressed with the capabilities of the surface generation and raster manipulation transformers in FME. Coupled with the rich set of vector feature transformers, you could almost put together a terrain modelling and image processing package. I tried out generating a terrain model in ESRI ArcGrid ASCII format from a LiDAR LAS file and I am quite happy with the results. To do a simple transformation, just do the following: