DTM, DEM & DLU

[s.sunilpal123]

Hello all...

I am working with Volcano add-in in Atoll for generating accurate predictions (considering multipath, etc.) using 3G maps. For this I have to have DTM, DEM, DLU files. Can u pls tell what exactly is the theoretical difference between DTm , DEM through examples...?

Also pls tell what exactly is a DLU file?

[proy1_10]

DTM: Digital Terrain Model Only mountains, hills, natural obstacles.
DEM: DTM+ Urban layer: (Terrain, hills,....)+buildings.
DLU: Digital Land Use: Type of terrain... Urban, dense urban, desert,.... terrain properties are different i.e.: if urban respect to fresh water.

BR

[drJaser]

DTM: Digital Terrain Model Only mountains, hills, natural obstacles.
DEM: DTM+ Urban layer: (Terrain, hills,....)+buildings.
DLU: Digital Land Use: Type of terrain... Urban, dense urban, desert,.... terrain properties are different i.e.: if urban respect to fresh water.

BR

Small correction:

DEM means Digital Elevation Model and does not include any buildings..
building heights are included in DSM (Digital Surface Model)..

or analogy : DSM = DEM + Clutter Height

source: Digital elevation model - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Digital_elevation_model)

BR,
drJ.

[vivainter]

Can you please share Volcano plug in ( with ********?) and also data for simulation building
Thanks

[proy1_10]

@Dr Jaser

Sorry, but term "dsm" not recognised by atoll/volcano.

Atoll uses DEM (Digital Elevation Model) as DTM+Building height layer.

BR

[drJaser]

@proy1_10 :

"Atoll uses DEM (Digital Elevation Model) as DTM+Building height layer."

Wrong. Don't mix tiger and lion even they are both big cats. Atoll uses what you import as DEM.. it's totally up to you.. You must understand what is your elevation data and what "buildings height" layer and finally be sure later how to adjust your propagation model against your clutter loss matrix.

Fact is that DEM is equal DTM regarding elevation numbers.

Copy/Paste from Atoll Help file:

Geographic Data

Several different geographic data types are used in an Atoll document. For example: the digital terrain model (DTM), clutter classes, clutter heights, scanned images, population maps, and traffic data maps are types of the geographic data that you can import or create. Some data types, such as clutter classes, can be used to give more realistic calculations. Other types such as scanned images, are used to create a more realistic display of the region under study.

Digital Terrain Model

The DTM describes the elevation of the ground over sea level. You can display the DTM in different ways: by single value, discrete values, or by value intervals (see "Display Properties of Objects").
The DTM is automatically taken into account by the propagation model during computations.

Clutter Heights

Clutter height maps describe the altitude of clutter over the DTM with one altitude defined per pixel. Clutter height maps can offer more precise information than defining an altitude per clutter class because, in a clutter height file, it is possible to have different heights within a single clutter class.

When clutter altitude is defined both in clutter classes and in a clutter height map, clutter altitude is taken from the clutter height map.

You can display the clutter height map in different ways: by single value, discrete values, or by value intervals (see "Display Properties of Objects").

Importing a Raster-format Geo Data File

Depending on the type of geo data file you are importing, choose one of the following options:

- DTM: Select Altitudes (DTM) from the Data Type list.
- Clutter Classes: Select Clutter Classes from the Data Type list.
- Clutter Heights: Select Clutter Heights from the Data Type list.
- Scanned Images: Select Image or Scan from the Data Type list.
- Population: i. Select Population from the Data Type list. The Use as ..ETC


ps:
Must mentioned that I spent a month with professional GIS company which created A'la Carte clutter files for my company, so I had to be really deep in map/GIS theory then...

BR,
drJ.