Lab 10: Distance Azimuth Survey

Introduction: 

GPS technology can be a great tool when completing field work. However, technology isn't always the most reliable and can fail at the worst of times. Learning how to conduct fieldwork using a non-technology based method could be very beneficial in the time of need. The objective of this lab was to conduct a distance azimuth survey. Tree data was collected along Putnam Drive at the University of Wisconsin-Eau Claire. The data was then organized and entered into an Excel spreadsheet to be imported in ArcMap and used to create useful maps.

Methods: 

Ten samples were collected at the first stop on Putnam Drive and then another six samples were collected about 15 meters away. A designated spot was used for a student to stand to take measurements for all of the samples to ensure accuracy for the latitude and longitude coordinates. There was a designated spot for the first ten samples and then a separate spot for the second six samples.  For each tree, the following attributes were collected: lat/long coordinates, distance, circumference, azimuth and tree type. To record the data, a series of instruments were used that don't all rely on technology: BadElf GPS, tape measure (Figure 1), compass (Figure 2), and a laser.

Figure 1: Compass to Measure Azimuth                                      Figure 2: Tape Measure Recording Circumference

The BadElf GPS was connected to an iPhone via bluetooth to collect the lat/long coordinates. The circumference of the trees were recorded in centimeters using a tape measure. The compass was used to record azimuth. This is where the designated spot was utilized. One student stood in the same spot on one side of Putnam Drive during the data collection of the first ten trees to ensure the azimuth was correct and that another student could then repeat the same steps and find the right trees that were analyzed in this lab. The direction shows on face of the compass but it is more accurate to look through the eye hole on the side. For measuring distance, the student standing at the designated spot held a laser that determined the distance to a sample tree in meters. All of the data was recorded in a field notebook during the process and was then later transferred into an Excel document (Figure 3). 

Figure 3: Data Organized in Excel

Then, the Excel table was imported into ArcMap and the Bearing Distance to Line tool was utilized (Figure 4). This tool creates a new feature class representing a line from the attributes. The azimuth data goes into the Bearing Field for this tool. The Feature Vertices to Points tool was also used on this data. This tool creates a point feature class containing all of the attribute data that was collected for each of the trees.

Figure 4: Bearing Distance to Line Tool

Results: 

Using graduated symbols, a map was created to show the difference of circumference between all of the trees (Figure 5).  The smallest recorded circumference from this data set was 12 centimeters to the largest at 116 centimeters, so there was quite the range. Looking at the map, one of the vertexes appears to not be located on the edge of Putnam Drive like the other; this was an error in our data. It was hard to find the problem that caused this slight shift but overall the rest of our data was relatively accurate. 

Figure 5: Tree Circumference

 Figure 6 shows the difference of azimuth in each tree with graduated colors. Most of the trees were recoded within 2 - 80 degrees.

Figure 6: Azimuth of Trees

Conclusion: 

Although technology is a fast and handy tool, it may not always be the most reliable. In this lab, a distance azimuth survey was completed using mostly non technological field tools. It is important to be able to know how to conduct research this way in the scenario that technology fails. Luckily, there are high-tech tools that can be used when completing surveys that have a much larger area to survey. GPS tools today have very high capabilities in recording extremely accurate locations amongst other abilities.