Bathymetric Mapping of Dells Mill Pond

Tools of the Trade

This is the Trimble GeoExplorer. It allows the user to set data categoriesand use them to store data to be transferredto the computer for use in the map.

This is a Humminbird depth locatorthis is used with the GPS to acquirewater depths, which are stored in theGPS and later put in the map.

More Tools

Moving about the lake is made easier by using anelectric trolling motor like this one. They are easyto use, and starting and stopping is very convenient.

I used a boat like this one. A flatbottom for stability and it does not need a lot of water to float in. The seats were handy for setting the GPSand depth sounder on.

GPS

The GPS is a very unique and useful tool. It uses satellites in space tolocate a way point on earth. These way points are then used to make themap. There are several different steps that must be taken to get the GPSset up before use.

1. System Setup: After the GPS has been stored for a while it needs to find the satellites again.

2. Enter Data Dictionary: This is a program that the GPS uses, it allows the user to select the type of data to be saved, whether it is, point, line, numbers, or one of the many that are available.

Data Dictionary

This is an example of aData Dictionary. The features are on the leftside, I have entered Depths. On the right are the Attributes, for this I have entered thedepths: 2,4,6. When I crossed a depth changeI would enter it in thecorrect attribute.

Getting the Shape

The first step to the mapping process is to make an outline of the pond. I used the GPS and the boat to follow the shoreline. Once that was completed I wentto the computer and saved the data for later use, with Pathfinder Office.

Collecting Data

Getting out on the water and actually getting the information that is needed was the fun part of this project. The best way that I found was to go in a zig-zag pattern. Every time a depth change was crossed its way point was entered into the GPS for later use. Getting good data is important for having an accurate map. I worked on both ends of the pond,while doing this I found that the north end had more irregularities thanthe south end. Because of this I had to spend more time on the north endgetting very accurate information. When I got to the south end I was able to go over it quickly because it didn’t change very much.

Information Processing

The first step in gettingthe data from the GPS tothe computer is to selectthe data transfer option. This will allow you to getthe information and startmaking the map.

Information Processing 2

This is the Data Transfer option. In thisstep the files from the GPS that are to be transferred are selected,also the place where it isto be saved is selected. This process transfers raw data from the GPS tothe computer. Because of government scramblingthe information must be corrected. The UFCORS is a web site that provides the necessary information, for correcting.

Correcting Files This is the web page that is used tocorrect the GPS Data. Certain numbers and otherinformation mustbe entered into theform, then the filefor correcting the files will be sent.

Get Unzipped

Because the files are zip files I hadto unzip them. This was easy enough,I used the program WinZip. The fileswere changed to a format that could be used by the computer. Now I was able to correct the data to be very accurate.

Formatting

Using Pathfinder and the differential correction option along with the correction files from the internet, all information was corrected. This movesall data points to the correct position, doingthis makes the map veryaccurate.

Starting the Map

Here is a sample of a map. The outline of the shore and some of the data have been added to the view the next step will be to add the rest of the depths. Then every depth category will be connected.

Connect the Dots

Here is the map withsome of the raw datafrom the GPS on the shoreline map of the pond. There are threedepths with differentcolors. Connecting the dots at each colorwill give depth contours for each value.

Getting Close Here is the map beforethe final touch-up stagesome of the lines runtogether, and some don’t go anywhere. These are all things that will be fixed before the final stage.

Wrapping it up

Here is the final mapthe keys have been inserted, the depths labeled, and the wholething has been cleanedup. Now all that is left is to publish it,and get it out to the public.

Useful Tools

Howie’s Funware- This was used to take pictures of the computer.

ArcView- This program was used in the map making process.

Pathfinder- Another mapping program.

Power Point- Used to make this presentation.