Distance Azimuth Survey

Introduction:

This project includes the class splitting up into groups once again and each taking data from a center points to different types of trees surrounding that point. Each group needs to create a survey plot that is going to prove useful when technology fails and backups are needed. The study area is a dirt trail right in the middle of a forest/swam full of different types of trees. Below is figure 1, which represents the study area of where points were taken by groups through GPS devices and the azimuth distance of each point to the center point is calculated.

Figure 1: Yellow blocks represent where the data was collected,
it is located on a dirt trail behind Davies and Phillips at UWEC

The figure above represents the study areas where the data points are being collected, the study areas selected are located on Putnam trail, directly behind the Davies Center on the University of Wisconsin - Eau Claire campus. This area is very swampy which is a good place for a variety of different types of trees to grow. This study area was selected because of the large variety of trees found in the area to take azimuth directions on. Once the groups arrived to the study area, they split up to three separate center points where the longitude and latitude were taken for each of the center points, next was to take azimuth distances to different species of trees found nearby. The groups were assigned GPS units to record the location for each tree origin in the survey. Along with measuring the distance of each tree there were more attributes collected, the azimuth, tree type, and diameter. Once all of the data was collected the groups combined all of the data into an Excel spreadsheet so than it can be used in ArcMap. Below is figure 2, representing the Excel spreadsheet created containing all of the data.

Figure 2: Excel spreadsheet for the survey containing all of the attribute data for each data point collected

The data collected was the longitude and latitude of each center point, then the distance from that center point to the trees chosen in meters for the survey. Along with the azimuth from the center point in degrees, the diameter of the tree taken at chest height, the tree species, and the sample area number. Once all of the data was collected the groups combined the data then moved to mapping out the collected data using ArcMap.


Methods:

This survey contained many steps, all of which are included below;

Step 1:

Locate the study area. This area must contain a large amount of different tree types and can be easily located using technology such as google maps for data accuracy reasons.

Step 2:

Obtain the GPS devices and measuring tape from professor and identify center point from which all of the data will be obtained from. Making sure that data accuracy is kept in mind when performing these steps.

Step 3:
Select ten different trees for the survey recording all of the data for each attribute.

Step 4:
Use a compass to obtain the azimuth by directing the compass at the tree in question for the survey.

Step 5:
Use the distance device provided by the professor to obtain the distance from the center point to the tree in question.

Step 6:
Figure out what species the tree is by the features of the tree, for instance, leaf shape, color of bark, texture, and other physical characteristics to determine the species.

Step 7:
Use the measuring tape provided to determine the diameter of the tree at chest height.

Step 8:
All members of the group record information collected for each tree for the survey

Step 9:
Transfer all of the data collected from the notebook to an Excel spreadsheet and combine with the other groups to have more data overall.

Step 10:
Convert the Excel Spreadsheet into a table on ArcMap, then perform the 'Bearing Distance to Line Command' tool to draw out the lines from the center point to the trees surveyed.

Step 11:
Use the feature class produced from the last tool used and use the 'Feature Vertices to Points' tool to use points at the end of each line to represent the tree taken from the center point.

Step 12:
Create a map of the end result from the data collected.


Below is figure 3, which represents the final map of the data collected.

Figure 3: Final points from the data collected in the field, representing the trees surveyed
distance from the center point

In figure 3, each tree that was collected in the survey is represented by a green tree, and the distance from the center point are represented by red lines each representing a shorter or longer distance than the last in meters.


Results/Discussion:

Initially there were a few problems that were encountered, nothing went wrong while collecting the data. But at first when the data was added, some of the groups added their data incorrectly which made a portion of the appear in the wrong location as can be seen below in figure 4.

Figure 4: Yellow boxes contain the data points collected from the original data 

Visible in the figure above is the data that was added incorrectly, the longitude and latitude data was added incorrectly for the study areas located most north and the study area at the very bottom of the map. One was initially located no where near the site where the data was collected and the other was located in the parking lot outside of the Davies Center approximately 30 meters in front of where it is supposed to be. This was solved by changing around a few of the numbers in the longitude and latitude so then the data appeared in the correct locations to where the data was collected. These methods are very useful when technology fails, and back ups are needed. As long as the right equipment is in the possession of the surveyor then all is well. A pro for this method is that it is easy to use as long as the data is recorded in an organized fashion, for example in a table format. The technology that has surpassed this method are distance finders and different types of GPS to collect data points. These points if collected through a survey grade GPS can log all of the attribute data collected in the field, and already compatible to transfer onto ArcMap for use. The results taken by group 1 were all in their correct locations it seemed, because all of the data collected was entered into the Excel spreadsheet correctly. But its hard to tell how accurate the locations of the data points are on the map because of how thick the trees are its hard to see through the cover provided by the trees.


Conclusion:

This was overall a good lab, the class including myself was able to learn survey techniques if/when technology fails in the field. The only major error in the survey was the incorrect GPS points logged in the spreadsheet so it is very important to use the correct GPS points. As well as logging all of the attribute information correctly so then there aren't any mistakes in the final product. The accuracy in this project was sub par because of how the tree covers was so bad the GPS locations were hard to pick up. Older equipment can be frustrating to work with in times, but it is a good skill to learn just in case its needed. It would have been more interesting to have collected even more data points so than the different groups could get a better idea of these methods, just in case its the only option in the end.