CE 547 – GIS in Water
Resources Engineering
Assignment 2:
Pan Evaporation Stations in
To give you a better understanding of the assignment and the map I am about to display in this assignment let me start by defining a few terms that we learned in class.
Evaporation – The rate of liquid water transformation to vapor from open water, bare soil, or vegetation with soil beneath (Shuttleworth, 1993).
Transpiration – Is the part of the total evaporation which enters the atmosphere from the soil through the plants (Shuttleworth, 1993). This process constitutes an important phase of the hydrologic cycle since it is the principal mechanism by which the precipitation falling on land areas is returned to the atmosphere (Lindsley, et al. 1982).
Evapotranspiration (ET) – Sum total of water returned to the atmosphere from surface and ground (soil) water, ice, snow, and vegetation.
I understand that these terms were drilled into your head as an undergraduate in Biology 101. I also understand that we all took freshman biology about 5 or more years ago, so a little refresher does not hurt.
The purpose of this assignment is Pan Evaporation. Although it sounds like a term that could be defined, it is not. It is a method scientist use to determine the rate of evaporation, where the data collected could be used in something called the water budget.
A class “A” pan that is 4 feet in diameter and 10 inches deep is needed. The class “A” pan will then be filled with water to 8 inches deep and refilled when the depth has fallen below 7 inches. The water surface level will be measured by a scientist/technician.
What I did in this assignment is, I first opened ArcMap and navigated to my assignment 2 files to display
the map of
After I got my labeling done I opened up the Attributes Table by right clicking on NMevap. I selected three pan evaporation tanks by using the Select Feature Tool in the Attributes Table and selected to show the three records selected by clicking the Selected tab at the bottom of the table. Also located at the bottom of the table was an Options tab. When you selected this tab it gives you the option to create a graph which I wanted to do. The Graph Wizard window will appear and you just take the necessary steps to create a graph you want. I choose to compare the annual pan evaporation and the pan evaporation in August.
When I was looking at my finished product, I wanted who ever was viewing my page to see in which counties the pan evaporation tanks were located. As I was in the Layout View of ArcMap, I opted to include the names of the counties. I inserted a new data frame by clicking on the Insert menu and clicked Data Frame. I clicked out of the Layout view and back into the Data View where I found a blank sheet. I dragged over the NMevap and Counties onto the blank page. I went through the necessary steps in the Table of Contents to display the names of the counties. This is where I got my finished product, the Display above.
I had a hard time displaying another map to compare and contrast the southern and northern pan evaporation. This is when I just decided to place a map with the names of the counties in the other data frame. I would have liked to have placed another graph in the new data frame to see the major differences in the North from the South.