CE 547 - GIS in Water Resources Engineering

ASSIGNMENT #3

Create a view of the world in a projection of your choice.  Provide a brief description of the projection and its parameters.  

Create a view of the contiguous United States.  Determine the approximate latitude and longitude of three cities.  What is the distance between Augusta and Olympia in miles if the view is not projected?  What is the distance between Augusta and Olympia in miles if the view is projected into Albers Equal Area?  What are the same distances in kilometers?  Which capital city is the most populous?  Which capital city is the least populous?  Which capital city has the highest elevation?  

Create a view of New Mexico using the query builder.  Create a shapefile called nmgeo.shp.  Use ArcToolbox to project nmgeo.shp into Albers with a -106 central meridian.  Bring the projected polygon back into ArcMap.  Create a layout with the state, listing the projection parameters.  

Place a projected view of the World, the United States, and New Mexico on your webpage.

You will find some specific instructions for changing projections in Getting to Know ArcGIS, Chapter 13.  Some additional instructions are provided by going through the tutorial below.

Start ArcMap.  Open a new Empty Map.

Add Data.  Navigate to C:/ESRI Data/ USA/ and C:/ESRI Data/World.  There are lots of data to explore here.  Each dataset includes a metadata (.xml) file as well as an ArcGIS layer (.lyr) file displaying symbols and classification for the dataset when viewed within ArcGIS.  Each SDC file also includes a projection (.prj) file that stores the coordinate system information that is by ArcGIS.  The published map (.pmf) files can be viewed with ArcReader and do not require someone to have the ArcGIS software.

Note that if you access the File Properties (click File on the menu toolbar and select Properties), you will have the option to make the data source be either an 'absolute' or 'relative' file name.  If you use a relative file name, you will alleviate some of the issues associated with using your USB drive in different computers that assign the USB drive different letters.

Add a layer that shows the United States.  There are a number of different layers that you can choose.  For example, you can add the USA Base Map or you can go to the census folder.  The examples below were created using shapefiles that are no longer included with the software data set (cities.shp and states.shp.)   Hold down the Control Key to select more data layers at a time.

(To create the projection of the world, you will need to add countries or continents

from ESRI Data/ World.  In addition, you can get the background lat/long map by going to USA/background/world30.sdc/world30)

If you find a layer with cities, you can decide to view the capitol cities only.  Right click the cities layer to access the layer properties.  Select the Definition Query tab.  Select the Query Builder button.  In the Query Builder Box, you will build a query.  Double click “CAPITAL” under the Fields list. Then single click =.  Then double click “Y” under the unique sample values list.  Make sure that your query says “CAPITAL” = ‘Y’.  If not, start over.  You are requesting that only capital cities be shown.  You could use the query builder to see cities with populations greater than one million using “POP1990” > 1,000,000.  When the query looks correct, press OK.

Note that the query is shown on the Definition Query tab.

You should now see only the capital cities.

Let’s display the cities according to their population.  Access the Layer Properties by right clicking on the layer name.  Click the Symbology tab.  Under Show: select Quantities>Proportional symbols.  Under the Fields box, change the Value to POP1990.  I chose to show three symbols in the legend.  You can change the color of the symbols by double clicking the box with the Min Value symbol.  You may click Apply to see if the view looks like you want before you click OK.

Let’s zoom in on the contiguous 48 states and label the cities by right clicking the layer and selecting label features.  Let’s also change the name of the layer to Capital Cities.  Access the Layer Properties, and depress the General tab to change the name of the layer.

Use the Window pull-down menu to access the Magnifier.  Place the Magnified window over Olympia, Washington.  Next, we’re going to measure the distance from Olympia to Augusta, Maine.  Select the measure tool.  and then click Olympia.  Use the mouse to highlight the blue bar on the top or the magnification window.  Move the window so that it is centered above Augusta.  Once the window is centered above Augusta, you can double click Augusta to end the measuring sequence.

In the status bar (bottom) you will note that both a segment and a total are measured.  Note the units of measurement is decimal degrees.

We want to change our measurement units.  Right click the name of the data frame “Layers”.  Use the general tab to change the name to the United States.  Change the display units to miles and re-measure the distance between Olympia and Augusta. 

Now let’s change from a geographic projection.  Right click the United States to access the Data Frame Properties.  Click on the Coordinate System tab.  Select the USA Albers Equal Area projection.  (If you need more instructions, refer to Chapter 13 of the text).  Press OK. 

Re-measure the distance between cities.  Note that you may need to change the display units (General tab) if you want miles.

Let’s determine the largest capital city and the one with the highest elevation.  Open the attribute table by right clicking the layer name and selecting Open Attribute Table.

When you right-click the name of a field, you have the option to sort the table.

Why do think there are several values with –99?

Next, we are going to create a shapefile or feature class of New Mexico.  Use the Select Features tool (to the right of the zoom tools) and select New Mexico.  It should be highlighted in cyan.

Next, right click the states layer and choose Data>Export Data.  In the Export Data box, you can choose where your shapefile or feature class will be exported and whether it should be projected or not.

Project the shapefile using the ArcToolbox.  You should find this easy enough to walk through. If you're interested in the dialog that would take place at an ArcInfo prompt, instructions are provided here.