Reprojecting Spatial Data in ArcMap

This procedure describes one method of assigning a new projection to a shapefile using Arcmap.

• Run ArcMap.
• Add a data set that requires a new projection. For this example, add the roads layer for the Niagara region found under D:\DATA\Niagara\DMTI\CanMapv7_2\roads_clip.shp

Notice the latitude and longitude coordinates at the bottom of the screen. Some databases default to the Geographic Coordinate system leaving the coverage looking a bit distorted.

To change the coordinates of a spatial data set to a new projection and coordinate system, first define the projection of the data frame.

• Double-click on the data frame called "Layers" in the above example .
• In the Data Frame Properties dialogue box, click on the Coordinate System tab.

• Under "Select a coordinate system", navigate down through the directories to select the appropriate projection as follows:

Predefined > Projected coordinate Systems > Utm > NAD83 > NAD 1983 UTM Zone 17N

• Click "Apply". If prompted with a warning, click "Yes" to use the selected coordinate system.

• Click OK to return to the map window. The warning prompt may pop up again but click "Yes" and the new projection will be applied to the data frame.
• Notice the coordinates now reflect metres, as is consistent with the UTM projection chosen in this procedure.

• To apply this coordinate system to the shapefile permanently, right click on the roads layer and choose Data > Export Data.

• From the Export Data dialogue box, complete the statement "Use the same coordinate system as:" with "the data frame".
• Click the browse button . Navigate to an appropriate directory, enter an appropriate name and click "Save". Click OK to the Export Data dialogue box.
• When prompted to add the layer to the current map, click NO.

To confirm the change in projection has been applied, open a new data frame and add the exported shapefile.

• Select Insert > Data frame
• Click the Add Data button then navigate to the new file and add it to the map.

Notice the coordinates at the bottom of the screen reflect the UTM projection.

[an error occurred while processing this directive]