• SO432, Geographical Information Systems

    Exam 2, Fall 2009





    Short answer



    Longer answer






    Authorized reference:

    1. This test will be open book.  Students can use their own copy of the textbook, with any notes they have permanently written in it.  No papers can be attached to the text, and class notes and handouts will not be allowed. Books will not be shared during the exam.
    2. Calculators will not be allowed.  For the calculations, you may set it up and leave the answer in terms of a sum, product, or quotient, or you can make reason simplifications to get a rough idea of the answer.

    Read directions carefully.  You have a selection of questions for the first two parts of the exam.  Carefully select which questions you will answer, and only answer the correct number.

    Quality of your answers is important.   For full credit you should use correct terminology, and show that you understand the concepts involved.

    All work on this exam is individual.  You may not any materials (books, notes, computers), not listed above in the authorized references, and you may not use IM, texting, talking, or any other means to communicate with other individuals.

    Definitions:  define 10 of these terms with a concise sentence that clearly shows your understanding of the term, and not just that you can find the term in the index or glossary of the text:  Each is worth two points.

    1. ETOPO1:
    2. Unregistered image:
    3. Generalization:
    4. GUI:
    5. TIR:
    6. MLLW:
    7. Hard-copy
    8. Chart datum: a nautical chart uses MLLW for a local tide station as the chart datum for vertical elevations
    9. Metonic cycle:
    10. Temporal resolution:
    11. Topological operations
    12. Join and TLID:

    Answer 3 of the 4 short answer questions.  Each is worth 10 points.

    1.  NGA is about (hopefully) to define standards for DTED Levels 3, 4, and 5.  Which of these will be the "best", and how do you think NGA should define the horizontal spacing between data postings?

    2.  What is the difference between NAD83 and NAVD88?  Which do you think is more important for GIS users to be aware of?

    3.  NLCD was created using a supervised classification.  What does that mean, and how would it be different if it used an unsupervised classification?  How do you think the spatial resolution of NLCD compares to the Landsat TM imagery used to create it?  8/12 skips

    4.  What would you consider to be the biggest difference between GIS maps and those produced by traditional cartography?

     Long answer questions.  There are three longer answer questions, worth 40 points, which you must answer..

    (3) You found the map on the first page of the exam (removed for legal reasons)on the internet, and it will be perfect for a discussion you will have with your plebes tonight.  You would like to use this map as a GIS base map.  What will you have to do to use the image (it is a JPEG, and you have no metadata), and how hard do you think this would be to do?

    (3)  After you changed the data so your GIS would open it, would you be able to click on a state and get the number of electoral votes, or find all the states with more than 10 electoral votes?  How, or why not?

    (3) If you found that the same web site also had the same data as an ESRI shape file, would getting just the SHP file be a better or worse choice?  Why or why not?

    (3) If you found the data in an Excel spreadsheet with the State Name, a FIPS code, and the number of electoral votes, would that be usable to create a map like this?

    (3) Which type would each of the three options above be?


    JPEG               ____Vector  Raster_ Neither   _

    Shape file         ____Vector  Raster_ Neither __

    Spreadsheet     ____Vector  Raster_ Neither __


    (15 Points) You have been tasked to obtain digital map data for an upcoming operation, and got three different DEM files as seen on the previous page which unfortunately cover different areas.  Your analyst has prepared shaded relief and contour maps of areas in all three data sets, but you suspect they are not correctly paired in the table on the previous page.

    The top reflectance image is 1" SRTM (note hole), the middle is 1 m Lidar, and the bottom is 0.15" IFSAR.

    (10 points) These two views depict on topography.  What method is this, and what are the alternative methods?  If the alternatives have been shown in other questions, mention that in your answer.

    This is a lidar point cloud.

    (10 points) The images below show two DEMs covering the same area, and a profile across the area with the two DEMs shown in different colors.  What do you think is the difference between the two DEMs, and is there any reason to have both?


    This is a DSM (left) and DTM (right).  Not the vegetation in the profile on the right.