Send us your GPS traces! If you have a description of what the trail was like, send that too. Otherwise, we'll hike the trail and add the description.
The maps we provide on this site are a collaboration of the folks at TopoZone.com and our Mapping Services Group. Given a GPS trace, our software requests the appropriate map from TopoZone.com and then plots the trace points directly on the map. This gives you an accurate trail position. Maps with a 1:50000 or 1:25000 scale are generally used, giving enough detail so you can decide which branch of that creek you are just about to cross.
The maps generally span several panels. These panels are shown in the overview, which is under the Maps heading on each trail's page. Click on a panel to show the web page describing that panel along with the full size panel itself. You will probably want to save the map as a file on your local machine so you can print just the picture. The maps are designed so that you have all the information you need from the picture. (Except maybe for the waypoints, but if you wanted those, you should have put them into your GPS ahead of time, so technically you should not need those in the field)
We also add magnetic lines (the blue corners) on the maps. This allows you to use your compass directly on the map and align it to the magnetic N-S lines, thereby dispensing with the adjustment for declination. The declination used to draw the blue corners is usually calculated from the International Geomagnetic Reference Field model. This model only calculates the effect of the "main field", that which arises from the dynamo in the earth's core. There are other components to the local declination which include proximity to magnetic rocks in the earth's crust and other local anomalies. However, the "main field" generally represents about 90% of the total local magnetic field. We use it because 1) I have not found the data for the local, observed field as a function of latitude and longitude, 2) the declination of the "main field" changes at a rate of 4 min/year westerly in east Texas, and I have a feeling most of the maps that show 7 degrees might be a bit old. When we build the maps, we have the option of specifying a declination, so if any of you know for sure what the declination is, please feel free to e-mail at the address below.
You can find the individual maps from the appropriate trail description.
If you have any suggestions, e-mail the webmaster.