SO432, Geographical Information Systems

Exam 1, Fall 2006

 

Definitions

10@ 4 points

40

 

Short answers

 5 @ 12 points

60

 

TOTAL

 

100

 

 

This is an open book exam.  You may use your personal copy of the text book and any notes you have permanently written in it.  You may not attach any papers to the book, but you can tab the book.

 

Read the directions carefully.  You have a selection of questions for the definitions and the short answers.

Quality of your answers is important.   For full credit you should use correct terminology, and show that you understand the concepts involved.  Demonstration of understanding, and placing you answer in the context of GIS, is much more important than finding a random sentence from the book describing or defining the term.

Definitions:  define 10 of the 12 terms with a concise sentence that clearly shows your understanding of the term:  Each is worth 4 points.

 

1)      Bounding Box:

2)      ESRI shape file:

3)      Feature Identifier such as TLID:

4)      Flattening: used in ellipsoid definition (many skips)

5)      Lossless compression:

6)      Metadata: include examples of what's included or why

7)      MLLW:

8)    Neighborhood operations: (many skips)

9)      NGA :

10)  Precision:

11)  Quadrangle: (most skips)

12)  World file:

The next five pages contain 5 questions, each of which is worth 12 points.  You can answer on the page or on the back of one of the pages.  For each answer you should clearly show that you understand the principles and use appropriate terminology.

1)  Your father wants the best available map for a hiking vacation within the United States.  He has heard something about datums, and knows there is something called NAD 1983 and another called NAVD 1988.  He thinks that NAVD 1988 is newer and thus better.  Is he right?  Insure that you clearly explain what a datum is, and what is different about these two datums and any older datums that you think it’s important that he consider.  How would a GPS react to the two datums?

 

 Differentiate horizontal and vertical datums, and NAD27 versus NAD83.

 

  

 

 

2)  Discuss the terms fields/attributes, tuples/records, and relations/tables in relation to the following diagram and indicate why it is important for GIS operations:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3)  Why must raster data like a scanned map be registered (or georeferenced) before it can be used in GIS operations:

 

 

 

4)  Explain the purpose of the markings on the map above, and what they tell you about the map projection used in the map.  Where does this projection have the least distortion, and how can you tell?

 

No k distortion anywhere--no stretching in the latitude direction.  Not that you should have known, but this is a sinusoidal projection, also known as Mercator equal-area.

5)  Is this map raster or vector?  How could you tell (if you can’t, what you have to do so you could tell)?  What difference does it make to users of this data whether it is raster or vector?  Is the map displayed at a scale that is appropriate for how it was collected, and how do you define scale for digital map data?