Lab 1: Survey of Terrain Surface

Introduction

The purpose of this activity was to have us as a class attempt to use what rudimentary knowledge of surveying we already have along with a limited supply of surveying equipment we were provided by our professor to conduct a sandbox survey. We could use whatever coordinate system and method of measurement we so chose, which in the next lab will be further developed and perfected using additional faculty direction. The landforms necessary for the lab were a hill, ridge, valley, plain, and depression; all of which were contained within a four by four wooden perimeter set up below the UWEC foot bridge on the sandy river bank.

Methods

After being assigned to groups of 3, shown a brief example of surveying techniques we could implement, and supplied with the needed equipment, our group chose to meet up the following Tuesday to conduct the survey. We grabbed orange spooled string, scotch tape, a segmented ruler, and the wooden box and headed over to beneath the foot bridge. The setup location was just beneath the midday shadow of the bridge, and hopefully would be somewhat sheltered from any rain. After clearing the box surroundings and clearing the survey landscape of small vegetation we created the hill, ridge, valley, plain, and depression; making sure to pack the sand into place.

 

Next we cut 30 or so segments of string to cover the span of the box along the x and y planes to serve as the limits of each square we would be taking a height measurement of. As a group we decided on having the dimensions be a 14 x 15 grid with each square being 8 centimeters, if a centimeter from each side of the box was subtracted and accounted for, thus moving our grid in by one centimeter and simplifying the process of having the square's dimensions a whole number. Once all the strings were taped down and intersecting to form our grid we began our measurements of the elevation from the top of the strings, starting at A1 and continuing through the column to A15, then continuing on to column B.

 

We recorded the initial depth measurements by hand and then transcribed them into an Excel document later on where they would be adjusted and corrected in accordance with where the zero point of elevation would be according to the height of the box (18.4 centimeters), making it an accurate representation of the sand model with positive and negative elevation values.

Discussion

The resulting elevations on the x y grid are as shown below, first with the values being turned into all negative values and then secondly adding 18.4 to account for above and below zero point values, leaving us with elevations in relation to the base level of the box perimeter. The elevation of our terrain was moderately level with the valley and hill being the lowest and highest physical features at 6 cm and 27.5 cm respectively.

This finalized elevation data can be exported into an ArgGIS map to show the terrain surface in an easy to understand graphic with multiple renditions of the same data, which is what we will be doing in the second half of this introduction phase of our class.

Conclusion

Based off our impromptu attempt at surveying a simple constructed landscape I can already see how vastly complex this field of work can be without the use of sophisticated technology, and even with its use can be a time consuming and difficult procedure to properly do. From what data we have collected we should be able to construct a semi-accurate representation of the actual terrain, but with the future addition of more comprehensive procedures, tools, and measurement equipment we can slowly hone in on a near perfect rendition of our currently imperfect data.

Evaluation

Prior to this Lab I would rank myself on a scale of 1-5 as a 2 (very little knowledge) about surveying terrain and the procedures necessary to doing so. After completing this lab I would consider myself to be closer towards a 3 or 4 now that I have field experience and understand the fundamentals. I would agree (4) that this hands on approach enabled me to learn much more than if I had been given excplicit instructions because it forced me and my group to figure out the most effective procedures to take in relation to our end goal and then how to implement them while creating usable data for later GIS modeling.

Overall this lab and its structure is a success, my only critique is to include more exact due dates for the lab material so we know precisely when it is due (just a peace of mind thing so it eliminates any guesswork).