Exercise 1: Introduction to ArcView

CE 394K.3 GIS in Water Resources 
University of Texas at Austin 
Fall 1999

Table of Contents

Brief Overview of ArcView

ArcView is a software program, developed by Environmental Systems Research Institute (ESRI), which is used to do GIS analysis. It differs from ArcInfo in that ArcInfo is designed to develop GIS data while Arcview is designed to interact with GIS data which has already been created.

All activities within Arcview are organized with a Project, which may consist of a number of Views, Tables, Charts, Layouts and Scripts (Scripts are programs in the Avenue language and this exercise does not include user-defined scripts). The functions of Arcview include: displaying coverages in a view, viewing the related attribute tables of these coverages, relating attribute tables using a key field, plotting charts to display spatial information, and creating layouts of the view and related tables and charts.

Goals of the Exercise

Computer and Data Requirements

To carry out this exercise, you need to have access to a PC, workstation or MacIntosh system which runs Arcview, version 3.1. Several of the computers in Rms 3.301 and 3.302 in the Learning Resources Center (LRC) on the 3rd floor of ECJ have ArcView 3.1 installed. You need to download the following themes:
  1. A polygon theme of the counties of Texas, called Texas
  2. A point theme of pan evaporation gage data, called Evap
The themes which you need to complete this exercise consist of several files: evap.dbf, evap.shp, evap.shx, and texas.dbf, texas.shp, texas.shx, texas.sbx, texas.shx. You can get them from this Winzip file: ex1.zip. which you have to unzip using the Windows utility Winzip.   For UT Austin students the files are located on the LRC NT network in the directories class\maidment\giswr\avintro\ . They can be copied to your working directory over the network using filemanager.  If you don't yet have an NT Login account, login as ceguest with password ecj and save your work in the c:\temp directory or on a diskette in the a:\ drive.

Procedure

Please Note: The following procedure is a general outline which can be followed to complete this lesson. However, the user is encouraged to experiment with the program and be creative.

1. Start Arcview

Execute ArcView on your machine. On PC's this can be done by clicking on the Arcview Icon in the Program Manager Window.

When ArcView is first executed, a new untitled Project window is opened. This window includes several icons marked Views, Tables, Charts, Layouts, and Scripts. This is the main Project window, which allows you to create new Views, Charts, etc., or to open existing ones that you have already created in that project.

Help! If you are lost and don't know how to do something, ArcView has on-line help which is accessed by hitting the  symbol in the top right corner of the display window.

2. Display Themes in a View

Now, be sure that the View icon is highlighted in the Project window and click on New for a new view. Drag the view window out of the way and resize it if necessary. Add a new theme to the view by clicking on the  button on the top tool bar. These are Feature Data Sources (later we'll use Grid data sources). Go to your local workspace directory either by typing the directory name into the pathname box or double-clicking on the directory with the mouse. Highlight the two coverages shown: Texas.shp and Evap.shp (hold the Shift key while selecting the second coverage), and click on OK to add them to your View. They will each show up as a bar in the legend portion of the View window with the name of the coverage shown on it. For the View you are working with, the coverages Evap.shp and Texas.shp are called Themes. Click on the raised box to the left of the Theme names Texas.shp and Evap.shp to make a check mark and see the coverages displayed in the View window. Drag the legend bar for the polygon coverage (Texas) below that for the point coverage (Evap) to show points on top of polygons. Dragging a theme is accomplished by clicking beside the theme symbol, holding down the mouse and dragging the box that appears.

Save the Project

The Legends for these Themes can be modified as described below. Once you've got your Project set up, you can save it to a file by making the Project window active and choosing the menu option File / Save Project. The Project file that you save has the extension .apr and contains information about the structure of your project, including the pathnames to the data dislayed in it. The Project file is an ASCII file that can be viewed with a text editor if you are curious about what it looks like. It is wise to periodically save the Project as you carry out this exercise so that you can recover all your work in the event that Arcview crashes before you complete the exercise.

3. Adjust the Display of the Themes

The legend for a Theme can be adjusted by double-clicking on that Theme's name. This brings up the Legend Editor. Adjust the coloring of a theme by clicking on its Symbol box and using the  paint brush in the top right corner of the Color Palette which appears. Select Apply in the Legend Editor to get the new color. Close the Color Palette and Legend Editor boxes using the icon in their upper right corner.

 

You can zoom in or zoom out from a portion of the View window using  or . To zoom to the extent of active Themes, use the  tool in the upper row of the tool bar. A Theme is active if its legend bar in the View window appears raised.

By clicking the  icon in the View tool bar and then clicking on a map feature in the View you can find out information about any feature in the active Theme (a display of its record in the data table). If you click on a feature and don't see the correct record displayed, check to see that the correct theme is highlighted in the View window legend bar.

4. Open a Table

To View tabular information associated with a Theme, first activate the Theme of interest by clicking on the Theme name in the legend bar of the View window, then click on  in the top row of buttons to open the Table. By clicking on a row in a Table you can highlight that row and the corresponding feature (evaporation station location) in the map.

Notice how there is a one to one correspondence between a record in the data table and a geographic feature in the map. This table-map linkage is one of the key things that makes a GIS operate effectively. To make sure that the row you've selected is easy to see, promote to the top of the table using the  icon.By holding down the shift key you can highlight several features at once.

Selecting Features Geographically in the View

Geographic features from a particular theme can be selected graphically by highlighting the theme, clicking on the  tool, and then selecting the features in the view. Again, by holding down the shift key and you can add features to the set you've previously selected. You can also drag a box over a region on the screen and select all the features in that region. If you attempt to select features graphically and don't succeed, check that you've clicked on the theme name in the legend bar so that it is highlighted.

By clicking on the  icon you can unselect all records. By holding down the shift key and clicking on a selected record, it will be unselected.

The data that you are examining are summary statistics of pan evaporation records at various sites in Texas. The attributes of the data, shown in column in the data table, include the name of the station, the city it is located nearest, the datum (elevation above mean sea level of the station in feet), the beginning and ending month and year of records, the latitude and longitude of the station in decimal degrees, and the values of the monthly and annual pan evaporation at this site in inches per month or per year, respectively. You'll see that there are missing values at some stations. The stations at Hidalgo in South Texas, and Lubbock in North Texas make an interesting comparison of evaporation conditions in the State.

Selecting Particular Fields in the Table

In the Table associated with Texas.shp, there are many data fields. You can see all of these fields by scrolling to the right using the scroll bar at the bottom of the Table. You can determine summary statistics for a particular field by selecting that field (depressing its header label) and then selecting Field/Statistics from the Menu Bar. If you have records selected in the table, the statistics function will summarise the statistics of these records only. If you want the statistics of all the records to be summarised, make sure that you have cleared all the selected records using the  button before calculating the statistics.

  
 

5. Make a Chart

A chart can be plotted of one or more records selected from a table. Select a particular gage record by clicking on its symbol on the view or its record in the table. With the table open, click on the Chart icon in the Project window, select the items from the table to be added to the chart in the properties box and give the chart a name. For our exercise, we wish to plot the monthly evaporation, so highlight the months on the left hand side and click on the box labeled Add.

Again, multiple fields can be selected by holding down the shift key. Once this is done, click on the box labeled Add. After clicking OK, a Chart will be plotted. You can change the form of the Chart using items in the top tool bar.
The horizontal axis of the Chart is automatically labeled using the field names you selected for plotting. If these are too long to fit on the chart, you can make shorter aliases for these field names by making the Table active, selecting the menu item Table / Properties, and entering text into the column labeled Alias. For example, you can replace the label Jan_val with Jan, etc.

To Edit Features of the Chart, select the Chart Edit tool  and then click on the feature you wish to Edit. You can change the nomenclature of the legend and the chart title and location in this way.

If you hold down the shift key and highlight a second station in the View or the Table, its data will be automatically added to the chart.  Here is a comparison between the pan evaporation Wichita in North-East Texas, with Mount Locke in West Texas:

6. Make a Layout

A Layout allows a user to combine Views, Tables, Charts, Legends, and Text into one document for printing. To create a new Layout, double-click on the  icon in the Project window. To work with a Layout, it is useful to enlarge the Layout window (by dragging on the window corner(s) with the mouse). After enlarging the window, click on the Zoom to page  tool to maximize use of the window space. As illustrated in the image below, by clicking and holding the left mouse button on the furthest icon to the right on the lower tool bar, you can add a number of different objects to the Layout. From top to bottom, the objects that you can add are a View, a Legend, a Scale, a North Arrow, a Chart, a Table, or a Graphic. After selecting one of these items, you can draw a box on the Layout to specify the location and size of the selected object.

Begin by selecting a view  and drawing a box to accomodate it. When you've drawn the box, a dialog box will come up asking you to select the view to show in the box. Select View1, and you should see your view of Texas show up.

You can add another object template to the layout using the right hand side tool in the lowest row of the upper tool bar. Select the chart object  to add a chart. To connect the chart visually to the corresponding point in the view using the draw tool  which is selected from the list of icons under the  button. When drawing the line you'll find that it automatically snaps the end points of the line to the grid points shown in the Layout window. To stop that happening, click off Snap to Grid in the Layout/Properties window.

You can add text to a Layout using the  button. You can also draw points, lines, and polygons using . If you find that the lines you are drawing are not in quite the right locations, use Layout/Properties and click off the "Snap to Grid" box. To change the size of the text you've added, highlight the text and use Window/Show Symbol Palette and the text icon to alter the text size. Text size of 14 point is the default. Usually 24 or 36 point looks good in layouts. Similarly, to change the line thickness use the same pallete and select the Line icon. Line thickness of 1 is the default.   You can directly print your layout from the Layout window, or you can export the layout as a Placeable WMF (Windows MetaFile) and then import it into MS Word using Insert/Picture/From File so that you can add a commentary on what you did on the exercise.

7. Do Something Creative!!

Now that you are familiar with the operation of Arcview, make some new maps, charts or tables of different variables in places that are of interest to you. Some additional data showing for Texas on a 0.5 degree grid values of precipitation (mm/mo.), temperature (degrees C), and net radiation (W/m2) can be found in the folder \class\maidment\giswr\avintro\txclim and can be opened using the project file Texas3.apr. These files can also be downloaded using this zip file: txclim.zip.  An exercise showing how to display such data using similar values in West Africa is available as an Introduction to ArcView in West Africa. Save your old project and open a new one if you wish to display these data.

To be Turned In

A copy of your layout showing the map of Texas and display of pan evaporation or climate data in some form.  Please turn this in as a paper printout if you are an in-class student.  If you are distance learning student, please create an MS Word file or other word processor file, labeled as ex1name where "name" is your surname.  Use anonymous ftp to send this file to our web site at ftp.crwr.utexas.edu and put the file into /pub/incoming/homework1.

This homework is due in on Tues Sept 7.

Some example layouts produced by previous students in this course are shown below.

Example Layouts

Ok, you're done!

These materials may be used for study, research, and education, but please credit the authors and the Center for Research in Water Resources, The University of Texas at Austin. All commercial rights reserved. Copyright 2000 Center for Research in Water Resources.