Monday, May 12, 2008

Historic Aerials: Visualizing Change Over Time

There's been a fair bit written on Historic Aerials already, but check out the new article in V1 Magazine. I've been a fan of Historic Aerials site for awhile now, and a few weeks ago we had a chance to interview them. A lot of the comments from the discussion are encapsulated in the article, and overall it was quite interesting to hear Jim and Brett talk about the trials and tribulations of working with historic photography. They are heavy LPS users (mainly for orthorectification and image processing) and have processed massive quantities of orthos while building content for the site.

It's easy to spend a lot of time on the site: if you want to see a good example of suburban Atlanta's development check out our ERDAS office location:

5050 Peachtree Corners Circle, Norcross GA. There's imagery from 1955, 1960, 1972, 1978, 1988, 1993, and 2007. When looking at the older images it becomes apparent that the entire area was developed over the past 20-30 years.

Make sure you check out the "Compare Two Years" option as well - it allows you to compare a second year to your currently loaded year and then adds a "swiping" capability to the viewer. Very cool!


slingeman said...

Did you ask them if they take free data from GIS websites and sharge people money for the data? I looked in my area (seacoast New hampshire) and found that they had 1962 and 1974 data up there and were charging for it. I worked on the orthorectification of that imagery for two years. It was funded with public funds and meant to be freely available to the public. It's a shame these guys take free data and then turn around and sell it to people who don't know better. I'm not impressed.

Ryan Strynatka said...

I'm not going to comment on the source data because I don't have a clue about how the imagery was acquired or what the data rights/permissions are. However one would presume they would check the legality of the source imagery.