Georeferencing

SUMMARY

Links: Georeference historical imagery in ArcGIS Pro

Time: Altogether the training and exercises took about 2 hours to complete.

Insights: I enjoyed learning how to add external images to the ArcGIS Pro software for comparison and use. I can see that this would be a valuable tool in analyzing historical topography of an area, which is applicable in conservation efforts among other interests. Aside from the practical applications, it is also a powerful tool in visualizing data in a different way.

Work Flow

1.      Find target data, determine what information would be beneficial to add to the map.

2.      Locate images to import into ArcGIS pro.

a.      Note the image’s georeferenced coordinates.

3.      Add the image to the appropriate folder and open in a map in ArcGIS Pro.

4.      Use the “Zoom to Layer” tool to determine if the image showed up in the correct location (usually the answer is no)

5.      Under the Imagery Tab, open the Georeferencing Tool.

a.      On the Georeferencing tab, under the “Prepare” section, use the “Select SRS” tool to make sure the image is assigned the correct coordinate system.

6.      If the image is in the correct location (globally)

a.      Do you have the coordinates for the image? Using the “Add Control Point” tool, input the coordinates to the corners of the image

b.      If you don’t have the coordinates, move the image to the correct location, using the tools in the Prepare section of the Georeferencing tab to adjust until the image fits the basemap.

7.      To fine-tune the image to the basemap’s topography and make it more locally accurate, add more control points throughout the image to anchor it to the basemap and choose the appropriate transformation to bring down the RMS error.

SCREENSHOTS