Homework Assignment 5

After running the respective tutorial, read the following set of questions and write half a page paragraph about what you have learned from this lesson. At this point, you should be able to answer these questions or at least have them help you in writing your paragraph.

Post this paragraph, along with a screen capture, or two, developed from the results of the tutorial, to your CE531 homework page, then email the TA (include the URL to your homework page).

Also, download a DEM to cover an area of your choice (close to your home or so), load it in to WMS. Get a screen capture of contoured version or a 3-d/shaded relief of it. Post this image into the web page for today's asignment.

Always try to make your assignment page look as nice and professional as possible.

DEM Basics

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What does DEM stand for?
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Define Resolution. What is the resolution of 3 USGS arc-second DEMS and USGS 7.5’ DEMs.?

A DEM with a pixel size of 30*30 m is finer than of size 90*90m. Is this true/false? Why?

Obtaining a DEM is always a cumbersome and very expensive process. How do you agree with this?

Suppose you have a choice over 3 DEM resolution to choose from for your project, i.e. Coarse, Medium and fine. How would you decide on which resolution to choose from? Mention the criteria you would follow in your choice.

Extra Questions:

Here are some extra questions for you to think about.

In WMS what would you use for display options of DEM if you want to display an image/map in the background? And why?

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Why is it that we need to smooth DEMs?
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In WMS, when do we need to use a thinning factor while importing a DEM?

How are TINs created? And what are the limitations of a TIN?

How does “filtering” help in TINs and DTMs in general?

Mention three ways of creating a TIN in WMS. Discuss where/when each one of them could help or be better than the others.