Laboratory Exercise 3

 

Measuring Distance and Area in a View


Background

This laboratory consists of exercises from Chapter 11 of the lab text, Getting to Know ArcView GIS, with the data obtained from the accompanying CD-ROM (exercises 11a,b,c).

ArcView is a powerful desktop geographic information system (GIS) made by Environmental Systems Research Institute (ESRI). With ArcView, you can load any data that's linked to geographic locations and display it graphically as maps, charts and tables. You can also edit the data , change the way it's displayed, append additional data, create some of your own, perform queries to answer specific questions, or meet certain criteria, and analyze information statistically as well as spatially. Results can be shown as quality graphic presentations to print out or display your screen.

In this exercise, you will learn how to reference spatial data to the real world, and how to measure distances and areas in a variety of units using the digital maps associated with Chapter 11. You will discover that area and distance measurements are dependent on the projection that is specified. Each projection preserves a certain property of the sphere or ellipsoid, i.e. a conformal projection in which the lines of latitude and longitude meet at right angles, preserves the shape of a of an area and can also be used for calculating distances between points. Examples of conformal projections are the Lambert Conformal Conic and the Mercator projections.

An equal area or equivalent projection preserves the property of area, and as such is used when area is to be calculated in an analysis. Examples of equivalent projections are the Albers Equal Area and Sinusoidal projections.

In this exercise, you will measure distances and areas in different projection systems to see how these quantities vary with the projection chosen.

For more information on these concepts, refer to the University of Colorado's 
Geographer's Craft site.

Procedure

With the supervision of your instructor, or lab coordinator, use the Getting to Know ArcView GIS CD-ROM to carry out the directions of exercises 11a,b,c. The path to the exercises may vary from PC to PC, so check with the lab instructor or lab coordinate.

Report Format

Name:

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Q1. What is the length of the new water line from where the new water line begins to the proposed new housing development?

Q2. In drawing the rectangle that represents the soccer field, how do you set its exact measurements?


Q3. Record your actual distance measurements for the distance between New York and Los Angeles for the following coordinate systems:



Q4. For the following projections, list the characteristics that are preserved and those that are sacrificed:





If this form, for some reason, does not work, submit your Word- formatted answers by way of e-mail to:

gatemail@mail.hartford.edu