The Mighty Chattahoochee

Two mapping days in a row. 85 degrees today. I start at a litle after seven and quit when it gets too hot.

Printed out more basemap, and started out on the area west of the small powerline. This is a big area, with no obvious handrails to use. My usual tactic is to make a handrail out of something so that I can enclose an area, then radually work away on the interior. I used the northern boundary of the inholding, which has a nice forest road along it. I mapped that out about 700 meters, then mapped a stream north west all the way to the river. The terrain is very pretty here. The stream is in a wide reentrant until the last 100 meters when the hills close in on it and it passes through a two contour deep channel down to the river.

Then I worked my way back up one of the hills and discovered an area that had been logged 20 or 30 years ago. It was only logged along the very top of the hills and spurs. Very odd. This is all hardwood forest, and the loggers did not replant, but let the volunteer trees come back. As a result, there is everything from bare clay to grass, blackberyy canes to muscadines, and trees of every height. Mapping the vegetation changes will be a chore. I predict I will spend a lot of time trying to get this right. My usual tactic is to map the edge as a linear feature first. I tried that and managed to get confused, but by that time the heat was getting to me.

I uploaded plenty more pictures, including a couple of the river. Check them out.

Small Victory

Today I finished the area east of the small powerline over to Flat Rock Road. It's pretty satisfying to actually finish off an area, no matter how small. This section is narrow, no more than 200 meters wide, and I can use the powerline poles as references - after I put them on the map, of course.

Found some pits that someone had dug in this area, as well as the usual root stocks. Also finished the last of the pine forest, which has a narrow strip west of the road.

Worked my way all the way north to where the powerline bends to the east. Here I got totally confused. The photo and the powerline did not agree. I was right at the edge of the photo and I didn't have the next photo north printed out. Gave it up until another time.

At this point I have finished about 0.6 sq km.

By the time I got back to the truck it was 82 degrees. Whoo.

Tickless

The good news today was that I came back from field checking with not a single tick. Last week I picked up 20 or 30 seed ticks. So I went to REI in Atlanta and bought some Sawyer clothing treatment. This has 0.5% permethrin. I followed the directions religiously, spraying my shoes (running shoes), socks (Thorlo hiking socks - seed ticks go through the weave in these like a man throuh a barn door) and my hiking pants from the knees down. I wore my pant cuffs tucked into my socks, so I looked like I did in the Army with my fatiques bloused over my boots.

It worked. I checked my ankles several times during the day and found no ticks. The terrain was the same as last weekend - pine forest with lots of weeds, perfect habitat for ticks. So far, it's a success. I suppose I'll see as the summer progresses.

Finished the area east of Flat Rock Road and north of the power line. Also checked the boundary around the smaller inholding. This is just a few acres along the road with three houses in it.

Found an old homestead. You know you have found one when the privet is so thick you can't move. Long ago the homeowner planted a privet hedge and it escaped. Now it's twenty feet tall and covers everything. Photographed several old buildings, see the photo page.

The northernmost point east of the road is an impressive stand of 20 foot tall cane - also escaped from the old house just outside the boundary. Need a fishing pole?

So now I move on, west of the road and north to the river. Now it will become a chore to walk out and back to the area I am field checking each day - there is no other road access.

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]