Working with
Digital Elevation Models
and
Digital Terrain Models
in ArcView 3.2
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TABLE OF CONTENTS
INTRODUCTION ................................................................................................................................ 3
WORKING WITH DIGITAL TERRAIN MODEL (DTM) DATA FROM NRVIS, CITY OF KITCHENER, AND
CITY OF TORONTO ........................................................................................................................... 4
WORKING WITH DIGITAL TERRAIN MODEL (DTM) DATA FROM DMTI AND GRCA ...................... 6
WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM NRVIS.................................... 7
WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM GTOPO30 AND GLOBE......... 8
WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM NRCAN CDED ....................... 9
3D VISUALIZATION USING DIGITAL ELEVATION MODEL (DEM) DATA......................................... 10
LIST OF TABLES
Figure 1: Interpolating a Grid (IDW - NRVIS Dataset) ................................................................. 4
Figure 2: Converting to a TIN (NRVIS Dataset)............................................................................ 5
Figure 3: Importing from an ASCII text file (DMTI Dataset)........................................................ 6
Figure 4: Importing from a floating point raster (NRVIS Dataset) ................................................ 7
Figure 5: Importing from a band interleaved format (GLOBE Dataset) ........................................ 8
Figure 6: Importing from a USGS DEM format (CDED Dataset) ................................................. 9
Figure 7: 3D Visualization using a Grid derived from NRVIS DTM (NRVIS Dataset).............. 10
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INTRODUCTION
This documentation outlines the steps needed to work with Digital Terrain Models (DTM) and
Digital Elevation Models (DEM) in ArcView from the following providers.
1.
2.
3.
4.
DTM data from NRVIS, the City of Kitchener, and the City of Toronto
DTM data from DMTI and GRCA
DEM data from NRVIS
DEM data from DMTI, GTOPO30, GLOBE, and NRCan
The data from these sources come in a variety of formats, some requiring more pre-processing
than others. Steps will be provided so that the user can load the required dataset into ArcView
and perform some basic visualization. At the end of each set of instructions an example screen
shot will illustrate what the output would generally resemble (screen shots will vary based on
spatial extent, dataset provider and the interpolation method used).
The terms DEM and DTM are often used interchangeably. For the purpose of this tutorial the
term DTM will refer to those datasets which originate as point features. The term DEM will be
applied to those datasets which originate as continuous surfaces.
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WORKING WITH DIGITAL TERRAIN MODEL (DTM) DATA FROM NRVIS, CITY OF KITCHENER,
AND CITY OF TORONTO
File format: ESRI *.shp, AutoCAD *.dwg
Converting to a Raster (ESRI GRID) in ArcView
1. Begin by adding the DTM to a new view window. Click on ViewÆAdd Theme and
select the appropriate dataset
2. Turn on the 3D Analyst extension from the FileÆExtensions menu by checking the
appropriate box
3. Click OK to close the dialogue
4. Begin the conversion to a GRID format by clicking on SurfaceÆInterpolate Grid
Note:
If the current view contains more than one theme then make sure the desired theme is
highlighted.
5. Set the Output Grid Extent to be the same as the extent of the theme you are converting
6. Specify the output path and filename for the Grid and click OK
7. Set the Method to Inverse Distance Weighted (IDW) and the Z Value Field to the
attribute which contains the height values for the DTM. Some common attribute names
containing height values are Height, Spot, and Elev.
8. Click on OK and the program will generate a Grid from the DTM points
Figure 1: Interpolating a Grid (IDW - NRVIS Dataset)
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Converting to a Triangulated Irregular Network (TIN) in ArcView
1. Begin by adding the DTM to a new view window. Click on ViewÆAdd Theme and
select the appropriate dataset
2. Turn on the 3D Analyst extension from the FileÆExtensions menu by checking the
appropriate box
3. Click OK to close the dialogue
4. Begin the conversion to a TIN by clicking on SurfaceÆCreate TIN from Features
5. Select the desired dataset as the Active feature themes
6. Set the Height source to the attribute which contains the height values for the DTM.
Some common attribute names containing height values are Height, Spot, and Elev.
Leave the rest of the options set to their default values and click OK
7. Specify the output path and filename for the TIN
8. Click on OK and the program will generate a TIN from the DTM points
Figure 2: Converting to a TIN (NRVIS Dataset)
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WORKING WITH DIGITAL TERRAIN MODEL (DTM) DATA FROM DMTI AND GRCA
File Format: ASCII Text File *.asc
Importing to ArcView
1.
2.
3.
4.
5.
Begin a new view and select FileÆImport Data Source
Set the Select import file type to ASCII Raster and click OK
Select the desired dataset and click OK
Specify the path and filename of the Output Grid
Click on OK and the program will import the values of the ASCII text file into a GRID
Figure 3: Importing from an ASCII text file (DMTI Dataset)
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WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM NRVIS
File Format: Binary Raster File *.dem
Importing to ArcView
1. Begin a new view and turn on the 3D Analyst extension from the FileÆExtensions menu
by checking the appropriate box
2. Click OK to close the dialogue
3. Select FileÆImport Data Source
4. Set the Select import file type to Binary Raster and click OK
5. Change the List files of type to All Files (*.*) and select the desired dataset and click OK
6. Specify the path and filename of the Output Grid
7. Click on OK and the program will import the values of the Binary Raster into a GRID
format
Figure 4: Importing from a floating point raster (NRVIS Dataset)
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WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM GTOPO30 AND GLOBE
Note:
GTOPO30 [http://edcdaac.usgs.gov/gtopo30/gtopo30.asp] is a global digital elevation model
(DEM) with a horizontal grid spacing of 30 arc seconds (approximately 1 kilometer). This
dataset is a collaboration between the USGS and many government organizations from around
the globe.
GLOBE [http://www.ngdc.noaa.gov/mgg/topo/globe.html] is also a global digital elevation
model (DEM) with a 1 kilometer resolution. This project was headed by the Committee on Earth
Observation Satellites.
File Format: Binary Raster File *.dem
Importing into ArcView
1. In Windows Explorer navigate to the directory which contains the dataset (.dem) file
2. The dataset’s extension needs to be renamed to .bil (band interleaved format) in order to
be viewed in ArcView. This can be done by right-clicking on the filename and selecting
Rename. Change the three character file extension from .dem to .bil
3. Begin a new view and turn on the 3D Analyst extension from the FileÆExtensions menu
by checking the appropriate box
4. Click OK to close the dialogue
5. Select FileÆImport Data Source
6. Add the dataset natively as an Image Data Source
Figure 5: Importing from a band interleaved format (GLOBE Dataset)
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WORKING WITH DIGITAL ELEVATION MODEL (DEM) DATA FROM NRCAN
File Format: USGS DEM *.dem
Importing into ArcView
1. Begin a new view and turn on the 3D Analyst extension from the FileÆExtensions menu
by checking the appropriate box
2. Click OK to close the dialogue
3. Select FileÆImport Data Source
4. Set the Select import file type to USGS DEM and click OK
5. Select the desired dataset and click OK
6. Specify the path and filename of the Output Grid
7. Click on OK and the program will import the values of the USGS DEM into a GRID
format
Figure 6: Importing from a USGS DEM format (NRCan CDED)
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3D VISUALIZATION USING DIGITAL ELEVATION MODEL (DEM) DATA
3D Visualization Using ArcView
1. Begin a new view and turn on the 3D Analyst extension from the FileÆExtensions menu
by checking the appropriate box
2. Click OK to close the dialogue
3. Click ViewÆAdd Theme and select the desired Grid Data Source
4. Click on ViewÆ3D Scene
5. From the 3D Scene dropdown box, select Themes and click OK
6. Click on ThemeÆ3D Properties and set the Assign base heights by value to Surface
and make sure the appropriate dataset is selected in the adjacent dropdown box and click
OK
7. In order to emphasize the topography you can add vertical exaggeration. Select 3D
SceneÆProperties and click on the Calculate command button.
Tip: You can define the vertical exaggeration if the calculated value is not
satisfactory
8. Click OK and the program will exaggerated the height values by the specified factor
Figure 7: 3D Visualization using a Grid derived from NRVIS DEM (NRVIS Dataset)
David Findlay
June 2005
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