Field Activity 1: Surveying a Surface Terrain

Introduction:

The class was presented with the task of creating a miniature landscape out of snow and sand.  After the landscape was created the surface of the terrain was to be surveyed in whatever way deemed most appropriate.  The instructor, Joe Hupy advised that in order to survey properly, it would be best to create a customized coordinate system.  Using this customized coordinate system, it was required to measure the elevation of the surface at various points of the designed grid.  After measuring and recording these points, they were put into an Excel spreadsheet as x, y, and z data with z being the elevations, while x and y pertained to the measurement's location in the coordinate system.  Groups were assigned and were given tools such as tape, meter sticks, and string to accomplish this task, though there were no limits set to what tools could be used.  This activity involved thinking independently of instructions and using critical thinking as a group to accomplish this spatial task.

Methods:

Group members began by discussing and deciding which tools to bring to help accomplish the set task.  The tools that were brought and used included:  pins, string, a hammer, measuring sticks, and some hand warmers as the temperature was well below freezing.


The terrain was initially set up as a flat surface level with the wooden sides
of the sandbox.  The features were then dug out from there, with some of the
higher elevation features being level with the wooden side. (Figure 1)

The group met and ventured into the below freezing temperature outside.  One of the first steps the group took was to level off the snow to the same level as the wooded sides of the box as pictured above (Figure 1).  From there the group dug out valleys and other features (Figure 2).  The features such as hills designed out of the snow were kept from having a greater elevation than the wooden sides to help keep the surveying as simple as possible.



The landscape begins to take shape containing features such as a hill, ridges, and valleys. (Figure 2)

The grid was set up every three inches in the x and y directions (Figure 3).  A pin with string was placed at each grid line to measure the elevation.  Measuring and placing the pins was made more difficult due to the cold temperatures and threat of frostbite, thought the group was pleased with the final survey results and grid looked to be laid out well in the correct positions (Figure 4).

The grid was laid out 3x3in and held together
with pins in the side of the sandbox. (Figure 3)

The final grid laid out covered the whole sandbox.
Many fingers were sacrificed to the cold to
accomplish this. (Figure 4)

It was then determined that each point would be measured at the upper right hand corner of the cells where the strings intersect (Figure 5).  Measuring may have been rushed due to the weather and the groups desire to head inside to the warm weather.  Shifts were taken as far as to who would be doing the measuring and who would be inside warming up.





Grids were measured by looking at the intersection between the strings on the top right corner of each square formed by the string.  This particular point being measured is (2,3). (Figure 5)

The measurements of the difference between the surface and the string (max height) were recorded into an excel spreadsheet (Figure 6).  The final point count was 420 different measurements.  These measurements were all recorded as negative values as they were down from the string.  In order to adjust this to better analyze the data, the lowest value was found (-15.6), and was added to all of the points to come up with a "z-adjusted" field.  In this field, the lowest elevation recorded was seen as zero, while the highest was 15.6.  These z measurements were done in centimeters.



This is a sample of the recorded data showing the adjust z value as well.  Overall, 420 points were recorded. (Figure 6)






































Discussion:

The surveying method which was decided on took quite a bit of time as placing a pin every three inches all around the sand box was no easy feat.  However, thanks to the decided method, over 400 data points were gathered overall.  This will likely help the data appear more accurate and minimize poor measurements and other sources of human error.  The cold weather didn't make this any easier as near frost-bitten fingers aren't the best for trying to make accurate measurements or for typing data accurately into a computer.  To combat this, the group took shifts as to who would be measuring, placing pins to create the grid, typing results in the computer, or warming up inside.  The technique of building down from the sandbox sides paid off greatly as it allowed us to measure as accurately as possible, seeing that the string was always at the same level which helped eliminate optical illusions and estimating (Figure 5).

Conclusion:

This exercise challenged the group both mentally and physically (sub-freezing temperatures), but it was an excellent opportunity to learn how to properly set up a coordinate system and use it to record elevation measurements of a terrain.  The class was asked to get creative and improvise, which is something that will be very much required when doing any type of field work in the future.