Occassional thoughts about orienteering

Monday, November 21, 2011

Comparing the map and the lidar data


Here's a comparison of the current orienteering map and some laser scan (aka lidar) data of the same area. First, take a look at the current orienteering map with 5 meter contours.
I'm not sure of the source of the contours. I think it might be USGS "DEM" (I think DEM = digital elevation model). Now, take a look at the laser scan contours. The countours are drawn at 2.5 meters (with a little bit of smoothing). I think you'll notice that these contours are a bit more detailed.

Finally, take a look at the laser scan "slope" image. In the slope image, the steeper the slope, the darker the shade. The slope image is especially useful for picking out the earth banks along streams and erosion features. In this area, you can also see some of the older trails (look for the trail that runs parallel and just to the east of the road on the top of the hill).

I used OL Laser to generate the contours and the slope image. I'm a fan of OL Laser. I find it fairly easy to use and I'm able to get a lot of information out of the laser scan data without a lot of work.
Back to okansas.blogspot.com.

posted by Michael | 7:17 PM


Always interesting to read your laserdata experiences. Have you try out the steep tool?
Best regards /jerker
I have to admit that I'd been using version 1.1. After I read your comment, I moved to 1.2 so I could test the tool. It seems to work well. I generated cliffs for a section of forest that I'm familiar with. The cliffs fit quite well. I need to do some more experimenting with the settings to see if I can get it even better.

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