The extract raster DEM functionality allows the user to create a raster DEM (i.e. : an image whose pixels contain elevation data) from a region of a Scalable Terrain Model (i.e. : STM).
Here is a short video showing the extraction of a raster DEM and the attachment of the generated raster DEM in Raster Manager.
Usability tip : As the video shows, the region of the STM from which the raster DEM need to be extracted cannot be too large. So using a more precise region (e.g. : road corridor, terrain not rectangular) will optimize the chance of being able to extract the contours for the desired region in one pass.
The extract raster DEM functionality supports a few different file formats for storing the DEM information.
Performance Tip : Use the Internet TIFF file format for best performance and interoperability with MicroStation`s Raster Manager,
There are also two pixel types that are available for storing DEM elevation in the raster DEM.
Precision Tip : Use the 32 bits floating point number for increase precision and if you want to keep the digit after the decimal (e.g. : centimeter precision).
For pixel whose center doesn`t overlap any terrain data (i.e. : outside the boundary of the STM) the no data pixel value (i.e. : the pixel value used by default) is -32767.
The vertical unit of the DEM raster is the same as the vertical unit of the STM.