Conducting a Distance Azimuth Survey

GEOG 336

Charlie Krueger

Conducting a Distance Azimuth Survey

Introduction

For this lab assignment the class was given the task of gathering data on trees that were surrounding Putnam Park trail. Gathering data would be done by using different methods of finding out the distance and azimuth different trees were from the starting points given by Professor Hupy. Different methods where going to be used in this lab because of the fact that technology can fail in different ways such as running out of batteries while other more basic methods can not. Professor Hupy lead the class out to the assigned area and then choose three different points that different groups would then collect data at. There the class learned about the different methods that would be used to collect the data of the trees. There were several things the class was looking for when sampling the trees and these were GPS location, distance to the tree, azimuth, species ID, and DBH or diameter at breast height.  First the professor located the GPS locations of the points where the groups would take the sample. This was done with a GPS called a BadElf which was just a small hand held unit. The first method that was used was the basic method of measuring out the distance with a meter tape measure that was pulled out from the beginning spot to the tree that was being sampled. Then with an azimuth compass the user would look through the hole of the compass and face towards the tree that was being sampled. This compass would give the azimuth in degrees and the user would have to read it from the compass. Then the DBH would be measured with the DBH tape which would give the diameter of the tree by wrapping the tape around the tree and reading where the end landed. This was the only instrument that was not replaced by technology. The next method that was used was using technology to measure the distance. The sonic distance finder had two components where one person would hold the measuring component to the tree and the other person would hold the other device and then press a button which would give the distance in meters. Using this method a person would still have to gather the azimuth using the azimuth compass. Again the DBH measuring tape was used to get the diameter of the tree. The final method that the groups used was the Tru Pulse laser which was the highest tech that was used. It was used by pointing the device at a tree and when looking through the eye piece and pressing a button the device would bring up the distance from the tree. Then  by switching the functions and repeating the process the device would give the azimuth. 

This is the Tru Pulse Laser that was used to collect the azimuth and distance. It is used by aiming the device at the object that is being survey and then pressing a button and the information that is need appears to the user while looking through the eye piece.

Methods

            The area of study that was used for this lab was the Putnam Drive trail and is located near the parking lot behind the Davies Center of the University of Wisconsin Eau Claire. Here was where Professor Hupy selected the points from which the groups would gather data from. Three different points were chosen and then the groups were spread out among them using the different type of distance and azimuth collection methods. At each point the groups were responsible for recording data on 10 trees so in total the class would have data points and distances for 30 trees. At each tree the data of the distance in meters, the azimuth, the species of the tree and the DBH were recorded to make the data table. The data that was collected from the groups were placed in notebooks when out in the field and then later transferred over to a shareable excel sheet. This excel sheet made it so that each member of the class could assess the data and members could catch problems and mistakes that others could have made. Here is the link to the spread sheet.

https://docs.google.com/spreadsheets/d/1c1jgCWHgtK-0bj9rEwKJm1O04ERwHYWHP0fgkjyO3EU/edit#gid=0

After the spread sheet was created with all the correct information it was taken and saved in a filed that could be assessed through ArcMap. Before that the sheet had to be made into numeric so that ArcMap could use the data. When the data was in ArcMap a tool called bearing distance to line was used and showed the distance and azimuth data in the form of lines on a map.

Here are the distance and azimuth lines that were created using the bearing to distance line tool in Arc map

Next in ArcMap a tool called feature vertices to points was used and this gave the ends of the lines points. By giving points to the lines it helps the viewer of the map know that these were the locations of the trees that were being measured.

These are the lines with the dots of the tree location. This was the result of using the feature vertices to points tool in ArcMap. 

Finally a  base map was placed onto the map to show where exactly the sample had been taken from and it also helps people see how the lines and dots make the connection to the trees.

Here is the final map with the data points laid over a map of real world imagery

Here is a different finished map with a different base map

The only problem that the class ran into was that of the GPS location of the starting measuring points. The GPS must have been off which then made the map look goofy when the data was added into ArcMap. So to resolve this, the only option was to look where the group had collected data from and then reassign GPS coordinates to the data that was messed up.

The best technique that was used was the one using the Tru Pulse laser technology. In this this situation it gave the most accurate results and did not take as much time and the others did.

Conclusion

This lab was very beneficial when looking at the multiply ways that data can be gathered. It was all the same data that was being gathered but when using different technology it can effect and even change the results. This lab shows that even when out in the field and technology fails there is always a way that does not use the high tech equipment to get the job done with good results. Technology did fail the class in this activity and set back the creation of the map because of the correction of the GPS position. So even with the best technology even something as small a couple of degrees in latitude and longitude can mess up a whole set of data.