OrthoPhoto Fix

A quick fix should make the orthophotos (air images) align properly with the rest of the Delaware GIS data:

The problem is that the units of measurement for the orthophotos is in meters, and the units of measurement for the other Delaware GIS data is feet. So change the units of the orthophoto files to feet and the problem should go away:

1. open ArcMap and create a new empty project

2. add the road centerlines: Delaware Data/Delaware Roads folder

3. from the Tools menu select ArcCatalog

4. select the Delaware Data folder in the left window in ArcCatalog

5. double click on the OrthophotoAp2006 folder in the right window in ArcCatalog

6. click once on Delaware_2006_Half-ft_North.sid in the right window in ArcCatalog

7. from the File menu select Properties…

8. a window will pop up: Raster Dataset Properties

9. scroll down to Spatial Reference and click on the Edit button

10. click the Modify button on the window that opens

11. in the Linear Unit box select Foot. Hit OK, then OK, then OK to get back to ArcCatalog.

12. repeat with the Delaware_2006_Half-ft_North.sid file (repeat steps 6 to 11).

Add the orthophoto to the ArcMap file with the road center line. The orthophoto should align properly.

I will put a lower resolution orthophoto on the computers, as the two high res files (north and south) take a long time to open on our older, white computers. When that is complete, you will have to go through the same process as above to change the units from meters to feet. I will let you know when that happens.

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