So I am running some test to decide on the next step strategies for upgrading the Imaging Place project. It used to be that aerial orthophotographic data was produced in the U.S. by a network of skilled aerial photographers working primarily with 9×9 inch roll film cameras through The National Aerial Photography Program (NAPP), an interagency Federal effort coordinated by the USGS. The best of the images which appear on Google Maps are still produced that way. However, with the phenomenal popularity of Google Maps commercial providers such as Digital Globe are able to finance launching increasingly sophisticated imaging satellites such as WorldView-1. Operating at an altitude of 496 kilometers, WorldView-1’s panchromatic imaging system is capable of collecting up to 750,000 square kilometers (290,000 square miles) per day at half-meter resolution imagery. Here in a 1:1 pixel detail of the data set I bought for Imaging from Digital Globe in August 2007.
The resolution is very good and I expect it will be getting better. The detail of 9×9 inch aerial roll film photography is pretty tough to beat, though. As I understand it there are strict standards for altitude, tilt, roll, pitch and atmospheric clarity to qualify for the USGS image bank. I was researching this back in 2000 to see if I could commission images at elevations lower than the standard. I found a photographer/pilot at Lawrence Airport who has a business Four Star Aviation. Here is a shot of his Cessna.
This is a shot of the camera.
Here is a full-frame scan of a 9×9 contact C-print flown, I believe at the minimum altitude allowed by the FAA over Cambridge.
You can see that the detail is quite remarkable.
Here is a comparison with the Mass GIS data set of the same area.
Here I pasted the two images to 10×10 meter scale in Second Life to approximate 512×512 file textures. You can see from this image that with the Four Star image I could put a pano node on each of the four corners of the street without crowding them. This means I could be working more or less to scale in Second Life.
One last thing. Here is a screen shot for Google of the same street corner using Mass GIS’s 2008 data, which is not yet available to the public. I scanned the Four Star print at 300 ppi. I will scan it a little higher to see if I can match the 2008 data.
The goal is to get the avatar to be able to walk across the image in avatar scale.