Stereoscopes/aerial photos

[Dan T]

I was having a recent then vs n ow discussion with a friend. We got on the topic of a tool/resource that used to be very invaluable to use before computers made life easy and in some aspects of our lives settled for less quality and more convenience, stereoscopes and stereoscope imagery. When I was in college for forestry in the mid 90's I took a pair of Mapping and Surveying courses, and aerial photography. This is where I learned about stereoscopes and aerial photos. Pretty much every county in every state has a US Department of Agriculture office. They usually have a library and one of the things they keep is transect photos of the entire county. The transect photos are taken flying a grid pattern over the area, the area is grided off into numbered transects, they are then cataloged in the library where specific areas can be looked up by number. Once you look up the photos of the area you want to view at the USDA office, their should be a pair of aerial photos, two identical images of each photo with a scale on two sides. The images are then viewed under a stereoscope. The images are placed one on top of the other under the stereoscope(left over right if I remember correctly). The images are then slowly spread apart until the two pictures form one single original image. At this point, you look through the stereoscope and continue to separate the pictures slowly, at some point the image will appear three dimensional in amazing detail. Every little feature change in the land can be viewed, plant species identified, you can even accurately measure objects as specific as a tree, given there is a know height object such as a flag pole in the image in combination with the photo scale. The frequency of these photos will vary from office to office. Most are done at least every 10 years I believe. When looking up a pair of photos in the USDA library most areas will have a history of images dating back as long as there was an office established there and a place flying over head. You can view the time lapse of change of each area going back decades. You can see how rivers and streams change course, when that clear cut was made, etc.. I found stereoscopic imagery to be much much more detailed than any online imagery to date, it's a truly three dimensional view. The online stuff is much more convenient and suits most needs, but I was thinking back to when this was the status quo for me when planing a trip or scouting a new property. I didn't now of where else to get overhead imagery of anything let alone a specific piece of property, and with incredible detail, still unmatched in my opinion. Has anyone else ever used or still use stereoscopes? Some of those images you want from google earth but can't always get like winter imagery, are most likely available at your local USDA office. Thought it was an old resource worth mentioning any how. Both the stereoscopes and images are available for public use at your local USDA office.

[stash59]

I had the cartographers at the Missoula, Montana office of the National Forest Service show me those maps and the scopes. They were using computer programs that used the stereoscope technology for all off the new forest service maps. That also included the topography. Something that they didn't offer previously. Those maps are great. You didn't need to go and buy separate topos anymore. For Forest Service owned land.

Didn't know the public could go view them at the USDA. This all comes from the milataries' "SMART" bomb technology. Real cool stuff.

[Perfectionitz]

This sounded awesome, so I called my local USDA office and they said that I wouldn't be able to look at any of the stereoscopic imagery without the permission of the property owner. I only am hunting public, so I inquired about public land and they said that the town would need to grant permission....

I think I may just go down there and ambush them and talk to them directly. Its a hot summer day and the receptionist may not have understood or wanted to deal with me. Ha.

[Dan T]

This sounded awesome, so I called my local USDA office and they said that I wouldn't be able to look at any of the stereoscopic imagery without the permission of the property owner. I only am hunting public, so I inquired about public land and they said that the town would need to grant permission....

I think I may just go down there and ambush them and talk to them directly. Its a hot summer day and the receptionist may not have understood or wanted to deal with me. Ha.

You may have been told correctly. I guess it's been too long since I've last been and I may have been misinforming everyone with my post. I called my self today after reading your reply and was more or less told the same. I guess Maine no longer has complete sets of back dated images in all county's any more either, the county office had some but not for public viewing. They don't even have stereoscopes any more. The woman I spoke with said those complete sets for the state were now held in one office in the state, and usually by the soil something or other department. Sorry to all for the misinformation. I hope this isn't a sign I'm getting old?

[Perfectionitz]

Ok, thanks DanT. Sounded great. I may still go down and talk to someone in the Department of Fish and Game and see if there is a way to get permission to view the public land stereoscopes. Definitely could see how there would be privacy concerns when viewing private land if the imagery is that detailed. Thanks for all the info!