Lab 6: Distance Azimuth Survey

Introduction

In this exercise, the class was provided an introduction to distance azimuth surveying.  This method of surveying is no longer commonly used, as it has been replaced by more sophisticated GPS technologies.  Despite this, possessing knowledge about distance azimuth surveying can be very useful in the case of technology failure, since it does not require many tools and can provide reasonably accurate results.  

For this activity, trees in Putnam Park were surveyed by small groups of students usually various equipment such as a compass, measuring tape and TruPulse 200 laser distance finder.  

Study Area

The study area for this activity was Putnam Park, a natural area located behind the University of Wisconsin-Eau Claire.  Trees at three different sites were assessed (Figure 1).  At each site, ten trees were surveyed from the same point.   

Figure 1: Study area for azimuth distance survey

Methods

At the beginning of this exercise, the instructor introduced all of the students to each piece of equipment.  Due to the limited amount of equipment, small teams of students then took turns assessing trees at three different sites.  At each of these sites, the following data was collected for approximately 10 trees: 

• Latitude and longitude of site
• Distance: from control point to tree
• Azimuth: from control point to tree
• Tree Diameter: measured at breast height
• Tree Type (if identification was possible)

These attributes were chosen collectively by the class and instructor before data collection began.  It was determined that these attributes were most important for future analysis and eventual map creation.  After recording all of this data in the field, the data was entered into a spreadsheet (Figure 2).  

Figure 2: Table of data collected

Results & Discussion

The resulting data of this exercise turned out fairly well.  Although the table of attribute data is by no means perfectly accurate, it provides basic information about the trees in Putnam Park.  One major source of error in this lab is the fact that different students assessed each attribute, each with more or less accuracy.  Moreover, the equipment available at each site was different, which likely affected the accuracy of measurements.  For example, all of the measurements completed at Site 2 were done with the TruPulse, while many of the measurements at Site 3 were taken using the compass.  Another problem during this lab was tree identification, since many students had little experience in this area.  As a result, some trees surveyed may have an incorrect "Tree Type" attribute, which could cause problems if anyone else tried to locate these trees in the field.  

Conclusion

While distance azimuth surveying is no longer commonly used by geographers, it is still a very practical skill to know.  Though geographers are increasingly reliant on sophisticated technology, older basic methods are valuable as well, especially in the case of technology failures.  This skill is also valuable if more expensive technology is not accessible.  For example, the instructor shared a story in which his GPS technology was seized at an international airport.