Thursday, September 10, 2009

Searching New Imagery for Change

When DC GIS acquires new imagery there is a a need to perform change detection. Among the things being searched for are:

  • New Buildings
  • New Streets
  • Demolished Buildings
  • Demolished Streets
The new 2009 1 meter Imagery is searched using a a grid which overlays DC. The grid has 350 squares.

While looking at the new imagery, I found two addresses 3203 Georgia Avenue NW and 3205 Georgia Avenue NW which appeared to be demolished (see image at top of blog post). Since the 2009 imagery is of of low resolution compared to DC GIS's 2008 Orthophoto Imagery, I wanted confirmation that these two addresses had been demolished. I check with USPS to see if they were considered deliverable. They were still deliverable (which is and indication that they might be still in existence). So I googled these addresses. I found these two images (3203 & 3205) on flickr which stated these addresses had been demolished. This information coupled with the 2009 Imagery was sufficient to change the status of these addresses to 'RETIRE' in the addresses from the MAR. Demolished addresses receive a 'RETIRE' status in the MAR.


Ryan Shepard said...

Very glad that my photos were of use to you!

Ryan Shepard (rockcreek)

David said...

Good to hear from you. Thanks.