A Beautiful Sunny Day

Finally some sunshine so I can get some field checking done. Spent about six hours walking to and fro and back and forth, still in the area along Flat Rock road north of the power line. Got a break about mid-day when the pine forest opened up with visibility of 200 meters at least through the scattered pine trees. That's a beautiful area - reminds me of the longleaf pine forest over at Choccolocco in Alabama. Of course, it will require diligence on the part of the foresters to keep it looking this good - burns at least once every two years would be good. Orienteers love controlled burns. They really clean out the undergrowth and encourage the larger trees.

Found a double decker tree stand, easily the tallest I have every found while mapping. Two photos are on the photo page. I did not climb it - too rickety for me, but I did put it on the map.

And the ticks are out. I probably picked up twenty or thirty - mostly seed ticks about the size of a pinhead, but also four or five dog ticks. I need to find some peremethrin(?) to treat my shoes and socks.

So a good day. The 0.3 sq km between the inholding and the eastern boundary along the road are now mapped. On the next trip I'll work on finishing everything east of Flat Rock road north of the powerline.

First field checking trip

Rain, rain, rain. I hoped to get at least one full day in this weekend, but the rain just keeps coming. I had to wait until Memorial Day to get a half day in between rain showers.

But the map is started now. I began with the area north of the powerline and along Falt Rock Road. There is a 400 meter wide and 800 meter long corridorhere which should be very important when we finally get around to setting orienteering courses here. Although it sounds small, that's still over 0.3 sq. km. I only managed to get 0.1 sq km done before the rain came back.

Field Checking ready to begin

The time has finally arrived. I have a good basemap consisting of LIDAR contours and aerial photos, and I have permission to make the map. Now all that is required is that I spend the time on the ground. This will take at least a year, maybe longer, depending on the level of detail that I encounter.

It's exciting to start a new map, but it's also a little sad. All the secrets of the park will be revealed. Every boulder, every fallen tree, every ditch and gully will be pinpointed (I hope) and drafted on the map. Making an orienteering map is a little like submitting to a full-body search - with photos. There will be no spot left unexamined by the time I am through.

And sometime in the not too distant future, several hundred orienteers will be handed the new map and sent out to see and find for themselves the hidden treasures of the park.

I have also added new photos to the Picasa web album I am keeping. I was out there (in the rain) last Saturday doing an "inventory" of boulder sizes. This is not mapping, but a walkthrough to set some standards. What will be the smallest boulder that I will map? Probably waist-high, unless it is a solitary boulder separated from its cousins. I also found very few rootstocks (fallen trees) and minimal ditches and gullies, but I restricted this inventory to just the area east of the bare rock.

LIDAR contours

The map took a major step forward this week with the acquisition of LIDAR contour data from the Coweta County GIS department. LIDAR is the latest and greatest method of generating contours (and other data) using airborne radar and digital signal processing. This is great news, and should make the finished product much better.

Getting it into a usable form took most of a day. The county supplied two foot contours in a shape file. I had to use qgis, wich is an open source GIS program (free) to translate it from lat/long coordinates to UTM WGS84 in zone 16N. Then I used a demo program to convert from shape to dxf. The dxf file still needed some massaging, which I did with sed in OS X. After all that I was able to import the dxf and have it magicall line up with the geo-referenced aerial photos.

Here's an example.The purple lines are the lidar data. The green lines are the USGS contours from the DRG. The blue lines are contours generated from the USGS DEM. There's a lot of difference.

[caption id="attachment_64" align="alignright" width="425" caption="LIDAR Contour Example"][/caption]