Lab 06- Working with DEMs
Table of Content
- Background
- Description
- Results
- Summary
- Reference
Background
This lab is aimed at learning how to use, manipulate and compare DEMs. I have been asked to construct a Digital Elevation Model (DEM) of the Big Cottonwood Canyon Watershed located off Wasatch Front in Utah. The map below illustrate the watershed of interest.
Click here for larger view
Description
I obtained the datasets of 2 m Lidar DEM, 5 m Auto-correlated DEM, 10 m NED DEM and 30 m NED DEM from USGS GIS portal. Click here for detailed method used in creating the DEMs for comparison.
Results
Find below the two maps created; one for DEM comparison and the other for proper view of the elevation peaks using contour
The map produced using different resolution showed a clear difference in the quality of image produced by each DEMs. It is obvious that the 2 m and 10 m DEMs gave images that are close to real life image. They will be useful for producing maps with more topography detail. The 5 m DEM look good too but not as the 2 m and 10 m, the image produced look rough. On the other hand, the image produced by th 30 m DEM looks blurry, this is due to more area being displayed within each pixel. I will recommend 2 m and 10 m DEM for the project because of the image quality. Click here for pdf of image comparing the DEMs
The 10 m and 2 m contour seems to be on point. The 30 m DEM show a clear evidence of deviation from the elevation peak points. Both the 10 m and 30 m DEMs have obvious pixel. However, the area captured within each pixel value differ; with the 30 m having more that is why there is a large digression of the elevation peak. The 5 m DEM also deviate a little. Click here for pdf of image of elevation peaks.
![](https://www.google.com/images/icons/product/drive-32.png)
The elevation points taken for each DEM are in the table here.
Summary
The choice of DEM for a project depends on the product desired, budget, time, and data storage.
Reference
Joe Wheaton 2016, Lab 06 - Working with DEMs. http://gis.joewheaton.org/assignments/labs/lab06-1/task-1. Retrieved on 28th February, 2017.
Utah GIS Portal, https://gis.utah.gov/data/#. DEMs. Retrieved on 28th February, 2017.