Tuesday, June 25, 2013

Oblique details

This is Part II of this week's series on oblique photos, a type of aerial photography that is of particular value in public safety applications. Lincoln's oblique imagery is from Pictometry, a firm that specializes in aerial photography and oblique imagery. Not only do Pictometry images provide a great perspective for public safety use, they are also shot from all four compass points, so you can actually rotate in 90 degree increments to get the view from each direction. Pictometry is available in Microsoft's Bing Maps for many parts of the United States, where it goes by the name "Bird's Eye View." The photos in Bing may be slightly older and at slightly lower resolution than Pictometry customers' latest imagery, but it is still mighty good.

Don't confuse oblique aerial imagery with some of those extruded building cityscapes or the computer-generated 3D perspective in some mapping applications.  Oblique aerial images are real photos, not simulated renderings.

Bing Maps Bird's Eye View isn't available everywhere, but a large percentage of the U.S. population is covered, and it's not just the big metropolitan areas.  This graphic shows the coverage area. Some surprisingly small towns are under the blue, such as Grand Island, NE; Bartlesville, OK; Fort Dodge, IA; Blacksburg, VA; Forsyth, MO; and Alexandria, LA, to name a few. To see if Bird's Eye is in your area, just search in Bing Maps. Be sure to turn on either "Automatic" or "Bird's Eye" up at the top left of the map image.

You might also check Google. Within the past year or so, Google has started adding oblique imagery of its own. Here is a coverage map you can check. With both Google and Bing, you'll probably want to remove some clutter.  Look for this little triangle in Google Maps, and click it to slide the sidebar out of the way.  In Bing Maps, you can do the same, but you can also click the link to "Full Screen" at the top right-center of the map to really maximize the image.

Once you've got your map centered, zoomed to your liking, you may want to grab a screen shot. The old-fashioned way is to use CTRL-PrintScreen, which copies the contents of your screen to your clipboard, after which you would paste the screenshot into some other application.  I prefer to use screen capture software.  Snagit is my favorite, but I also use Google's Screen Capture and Awesome Screenshot, which are browser add-ins.  There are tons of free-or-cheap apps and browser plugins for screen shots, and everyone should have one of these.

Check with your GIS manager, County Engineer, County Assessor, or Public Works department to see if your city or county are Pictometry customers already. If not, look to see if either Google or Bing Maps have oblique aerial imagery in your neck of the woods. If you have access to obliques from any of these sources, they can be incredibly valuable to police and fire, and we will explore a couple of typical use cases later this week.

1 comment:

ARRRRG!!!! said...

Satellite images sure make treasure hunting a lot easier.