CEEn 531 - Water Resources Engineering

Dr. Nelson

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Homework Assignment 3

Complete the Basic and Advanced Feature Objects WMS tutorials then read the following set of questions and write half a page paragraph about what you have learned.

Go to the GSDA wiki site at: http://www.xmswiki.com/wiki/GSDA:GSDA.  Under the surface characteristics sub-heading you will find a link to websites where you can download shapefiles for land use data.  Follow this link and then try to download land use for your selected watershed area from the WebGIS site.  What coordinate system is it in, do you need to convert coordinates when loading so that it will overlay correctly with the image data you downloaded in the previous assignment? Load the shapefile into WMS, convert coordinates if needed, make a new land use coverage and "map" the shapefile polygons to the WMS land use coverage.  Show a screen shot of your land use file on top of the image file you downloaded previously on your assignment web page.

You could also do soils, but we will save that for a later exercise.

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

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

GIS and Feature Objects

  1. What is the purpose of coverages in WMS?
  2. What is the basic difference between vertices and nodes?
  3. How is raster data different from vector data?
  4. List the three main components of shape files along with their description.
  5. List at least 3 topological problems that might appear when importing CAD/GIS features/Layers.
  6. What are the advantages of using a feature-object based model?
  7. What is meant by the topology of a drainage coverage?
  8. At least one stream arc must exist within each basin for the basin to exist in the tree. Why this is so? In other words, why can’t we represent the basin as an area of land that doesn’t have a stream in it?

Extra Questions:

Here are some extra questions for you to think about. 

  1. When are polygons created?
  2. Why attributes are considered an essential components in GIS?
  3. How similar are the terms “Topology” and “Topography”?
  4. How does the GIS module help in WMS?
  5. List the possible feature objects that are used in WMS along with their attributes.
  6. Can we represent a lined rectangular open drain in WMS? If so, how?