NRCan DEM (CDED) Conversion
from Decimal Degrees to UTM
Introduction
This procedure outlines steps to convert Natural Resources
Canada Digital Elevation Model data from decimal degrees to Universal Transverse
Mercator (UTM) projection using ArcView 3.2. The first step is
to convert the original data from decimal seconds to decimal degrees outlined
at http://www.brocku.ca/maplibrary/procedures/DEMshift.htm
This procedure will use the ArcView 3.2 extension called "Grid Projector" to assign the UTM projection to the DEM data.
Run ArcView 3.2. From the start up dialogue boxes, create a new view but do NOT add any data.
Select File>Extensions. Scroll down the list and put a check beside the "Grid Projector" extension. Click OK.
Select View>Add theme and change the "Data Source Type" to Grid Data Source. Navigate to the directory where you saved the DEM data in decimal degrees. Select the file and click OK.
Make the DEM visible by clicking in the box beside the legend. Select the theme to make sure it is active (will appear raised in the legend).
Select View>Properties. Make sure the Map Units are decimal degrees and the Distance Units are unknown. Click OK.
Click the Grid Projector button 
.
Select "meters" as the output units and click OK.
From the Projection Properties dialogue box select UTM -1983 from the Category dropdown list and Zone 17 from the Type dropdown list. Click OK.
From the next dialogue box select <New View> and click OK. It will take some time for the process to complete. Wait patiently. The new grid will appear in a new view.
Turn the theme on to view the data projected in UTM. Note that the coordinates in the top right corner of the ArcView window reflect UTM coordinates instead of decimal degrees.
To save a permanent copy select Theme>Save data set, navigate to the directory to save the data to, give the file an appropriate name and click OK.
You will now need to define the projection using ArcTools before you can view this data accurately in ArcView 8.2 software. This procedure can be found at http://www.brocku.ca/maplibrary/procedures/projecting.htm
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This page is: http://jeeves.brocku.ca/maplibrary/procedures/dd2utm.htm |