Exercise 1: generating digital elevation models

Geography 336 Sandbox creation

Creating and surveying points throughout a man made diagram

Dillan Berg

Background: 

Figure 1.1:   Sculpting our sandbox to specifications
 previously determined

The task our group was faced with was to design and survey our own structures within a 114cm x 122 cm sandbox. The parameters that our group was given was that we needed to included a ridge (elongated structure with a high point), valley (depressed that is longer than it is wide), a depression ( inverted hill), hill ( a elevated area that is not as long as it is wide), and a plane ( a flat area that ranges over a long distance).After construction of the features where built we were tasked to come up with our own form of surveying the features accurately and efficiently. Meaning we needed to have enough points to accurately show all the features but not to many to over collect and have faulty data. 

Methods:

We decided to take our total box which was originally 114cm x 122cm and cut off 1 cm from each side so we could accurately measure each grid. The new area of the box is 112 cm x 120cm.We then made grinds on both sides every 8cm, this allowed us to have a total of 210 sections within the total area to measure for elevation. We decided to keep accurate measurements by labeling the top of the grid by letters and the side by numbers. We then made each measurement within the grid in the lower right corner of each square. Since the features where all below the string we collected all negative numbers. To make the analysis easier in future applications we measured the width of the boards and added the width to all collected measurements. This helped by making all of our data points positive numbers but also keep accurate measurements of the true heights. 

Figure 1.2  Demonstrates the grid layout and our collection methods.

By labeling the top in letters and side in numbers it allowed for quick and easy entry into our excel spreed sheet. Once in excel we where able to transform the data by adding 18.4 cm to each measurement resulting in our final collection. 

Figure 1.3  Final data points of sandbox collected in cm

Discussion: 

Overall our collection went well we had very minor complication. We where able to set up design and collect all the points in one day. It was on Tuesday September 15, the weather was partly cloudy with a light wind and about 82 degrees. Since we where able to collect in one day we did not have to worry about our design being altered or destroyed. A few of our concerns with the collection where as follows. First we had some variation in collection since we where switching between two people measuring. Making it possible that one was measuring different than the other and could lead to slight variation in collection. Second we were not allowed to fasten the string to the wood with anything other than tape making it possible for the string to move or sway if you placed your hand on it. This allowed for some of the collection to be in the wrong spot from where we previously picked of lower right corner. Our last concern was that the area was not placed on a level ground which could have lead to altered measurement where we where not collecting at a perpendicular down angle leading to larger lengths than what was the actual measurement. 

Conclusion:

This activity not only interesting but represented a lot of tools that we will need for the rest of the semester. Some of those tools being critical thinking, problem solving, adapting to the surroundings, team work, and precision collection. The task covered all of these areas which we will be faced with for not only the rest of the semester but also into all of our careers. We where given a task with very little direction. I really enjoyed this activity and hope they continue to be similar task given to us. The task was not only challenging but continues to work on key skills that will advance any student to greatness in the workforce.