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Attackpoint AR - performance and training tools for adventure athletes

Discussion: finished map

in: PG; PG > 2011-08-07

Aug 8, 2011 2:14 AM # 
Thanks for posting the map - this is the first time I've seen the final product! Always interesting to see how a basemap "prints through" into the final map. And to see what I got right and wrong.
Aug 8, 2011 2:30 AM # 
And I posted a nice clean copy, thanks to the organizers for getting me one afterwards -- I put several holes in my original one sliding down the near vertical wall after 26, though fortunately only destroyed the first part of the course.

I thought the map was great. Didn't notice until later that it is effectively a 2.5 meter map in the flatter areas, 5 meter in the steeper ones. Not sure if that was your intention, but it seemed to work fine.
Aug 8, 2011 2:42 AM # 
My basemaps include intervals down to 0.5m. Its up the fieldchecker as to how to use that information, so the use of the formlines in the flatter areas on the final map was his idea.

I usually work with the 5m or 2.5m showing depending on the area (and if I know the final interval the mapper wants to use I'll work specifically to that). If I need clarification while drawing I might unhide the smaller interval lines temporarily. I think I did my work on this one at 5m. There was an existing 5m O-map of this area. They also asked me to warp that to the new lidar so they could use the old info while fieldchecking. Its interesting that the fieldchecker changed all my dry ditches to intermittent streams. The difference between those two could be pretty subjective. Of course I haven't been in the field so I have no idea what they look like. I just draw the shape and its up to the fieldchecker to do the rest.
Aug 8, 2011 2:45 AM # 
All the intermittent streams that I recall were bigger/deeper than what I think of as a dry ditch. Seemed appropriate as done.
Aug 8, 2011 3:15 AM # 
Good to know. I usually draw such features based on "strength" and context. Easy enough for the mapper to just change the symbol.

Here are the basemap materials for Chestnut Ridge (with permission from BFLO). There is a 200 DPI gif image of the base at the top of the page.

I see that your control 27 was on an intermittent stream bend. That feature was so weak in the lidar that I used a purple dashed line for it on the basemap rather than dryditch or stream. Look simply like the bottom of a reentrant. I use purple dashed lines for features I can see but feel are probably too weak to be on the final O-map. Clearly the fieldchecker decided they were strong enough to include, so I was too conservative.

The ocad basemap file is available too in case you want to look at the other contour intervals.

This image of the spatial distribution of the lidar returns is kindof cool. You can see the overlapping flight lines. The curvy edges of each line are caused by the plane rolling left and right to stay on track, and the bright and dark stripes perpendicular to the flight direction are caused by the plane pitching up and down, swinging the laser scanner forward and back causing the side-to-side scans to "bunch up" or spread out.

This discussion thread is closed.