okansas.blogspot.com Occassional thoughts about orienteering
Monday, September 06, 2010
Another day, another basemap
Another day, another experiment with a lidar basemap. The image below shows 2 meter contours, trails that I added last winter (based primarily on GPS tracks from a few trail runs) and the lutning image created in OL Laser.
The image is shaded based on the slope. The darker the area, the steeper the slope. I think that the slope is based on comparison of surrounding points. I don't know the details. A very dark area is vertical. A very light area is horizontal.
If you look at the north east section of the image, you'll see some rectangular dark areas. Those are buildings.
If you look in the bottoms of the larger reentrants, you can pick out some of the stream beds. The image shows the bank.
The hillsides are covered with irregular dark shapes. The hillsides at this area are forested. The forest is a mix or hardwood and cedar trees. The larger blobs generally correspond to cedar trees, individual or small groups. The cedar trees make useful points for fieldchecking. You wouldn't generally put them on the final map, but they help in locating point features and tweaking the trails. The smaller dark spots were generally the trunks of larger deciduous trees. It took a bit of practice to match up the trees with the spots. But, after a bit of practice, I felt like I was matching them up pretty consistently. The individual trees provide more points that can help with fieldchecking.
As Jerker pointed out in a comment, "lutning" means "slope" in English. But, I'm sticking with lutning. As I'm working with the software, I'm keeping some notes and it is a lot easier to use the Swedish terms (since the menus in OL Laser are in Swedish).
