Introduction to ArcGIS
Prepared by
Kristina Schneider, Francisco Olivera, and David R. Maidment
Center for Research in Water Resources
University of Texas at Austin
September 2002
Contents
Brief Overview of ArcGIS
ArcGIS is a software program, used to create, display and analyze geospatial data, developed by Environmental Systems Research Institute (ESRI) of Redlands, California. ArcGIS consists of three components: ArcCatalog, ArcMap and ArcToolbox. ArcCatalog is used for browsing for maps and spatial data, exploring spatial data, viewing and creating metadata, and managing spatial data. ArcMap is used for visualizing spatial data, performing spatial analysis, and creating maps to show the results of your work. ArcToolbox is an interface for accessing the data conversion and analysis function that come with ArcGIS. ArcGIS comes in three variants: ArcView, ArcEditor, or ArcInfo, which are the low end, middle and fully configured versions of the software. Any of these versions can be used for this exercise.
Goals of the Exercise
This exercise introduces you to ArcMap and ArcCatalog. You use these applications to create a map of pan evaporation stations in Texas, and to draw a graph of monthly pan evaporation data measured at these stations. The relationship between ArcGIS and MS Word and Excel is demonstrated so that you can create graphs in Excel, maps in ArcGIS and place the result in a Word file as a report for this homework. You use ArcCatalog to create a new personal geodatabase and import shapefiles and a coverage to a feature dataset, and thus you’ll have experience with all the vector data formats used in ArcGIS by the end of this exercise.
Computer and Data Requirements
To carry out this exercise, you need to have a computer, which runs ArcGIS.
You will be working with the following spatial datasets during this exercise:
- A polygon shapefile of the counties of Texas, called Counties
- A point shapefile of pan evaporation stations, called Evap
- A polygon shapefile of the state of Texas, called Texas
These shapefiles consist of several files (e.g. evap.dbf, evap.shp, evap.shx). You can get them from this Winzip file: ex12002.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 class directory class\maidment\giswr2002\ex1\. This directory can be found in the LRC using Windows Explorer at My Computer\My Network Places\Entire Network\Microsoft Windows Network\lrc\civil5\lrc\class. You need to establish a working account to do the exercise on. This can be in c:\temp or in the diskette or zip disk drive of the machine you are working on. If you don't yet have a regular NT Login account at the LRC, get a temporary guest login to do the exercise. If you use the Winzip file, double click on the Winzip file and you should see the Winzip utility open on your computer (if it doesn’t open you’ll have to unzip this file on a computer with Winzip operational). If queried, agree to use the Winzip system, then you’ll be presented with a list of the files inside the Winzip folder. Use Action/Select All to select all these files, then Action/Extract to extract them to the working folder that you’ve set up to do this exercise. You should end up with a file list that looks something like this.
ArcGIS
License Server
This exercise can be executed with any of the options within ArcGIS, namely ArcInfo, ArcEditor or ArcView. Each of these systems provides access to ArcMap and ArcCatalog, which are the ArcGIS interfaces used to do the work. When you invoke ArcMap or ArcCatalog, it is possible that you will get a message saying that all the licenses for ArcInfo are in use on the network, or that you aren’t licensed for this application. In that event, you need to switch to an application with available licenses. To do this, invoke the ArcGIS Desktop Administrator, and select another application. In the LRC, ArcView [Single Use] works best, but in another lab setting, the ArcView [floating] or ArcEditor [floating] could be the right choice, depending on license availability.
Procedure
Please note that 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. Viewing Shapefiles
A shapefile is a homogenous collection of simple features that do not contain topological information. The format was introduced with ArcView 2.0 to simplify the representation of spatial data. A shapefile includes geometric features and their attributes. The attributes are contained in a dBase table, which allows for the joining with a feature based on the attribute key.
Viewing Shapefiles in ArcMap
(1) Open ArcMap and select the A new empty map option.
(2) Use the 
(Add Data)
button to add the exercise data for this exercise. Navigate to the folder,
which contains the data, and select all three files at once by using the shift
key. Click the Add button to import the images. If you are using a network drive to obtain
your files use the 
button to add the network drive to the ones
that ArcMap is accessing so you can get to the files.
In ArcMap, a layer consists of a reference to a spatial dataset (such as a feature class, shapefile or coverage) and a definition of how to display it (legend colors, line thickness, etc.), and a map is a graphical representation of geographic information. The left panel in the ArcMap window is the Table of contents, and the right panel is the Display window. The Table of contents lists layers, and the Display window displays maps. You may get a message that says that “one or more layers lacks spatial reference information and can’t be projected”. Don’t worry about this. The Texas polygon layer has a projection file (Texas.prj) and the other files are in the same coordinate system. We’ll deal more with projections in later exercises. As you can see it is very simple to add shapefiles to ArcMap.
(3) Click off the check marks next to the file names in the left hand column. Reselect each file name individually to that you may view what features each file contains.
When you are done exploring the possibilities of ArcMap, exit the program. You do not need to save the file since you will be coming back to ArcMap later in the exercise.
Preview Shapefiles in ArcCatalog
(4) Open ArcCatalog
(5) On the left panel, search for the folder where the exercise data is located.
In ArcCatalog, you can toggle the right panel display between a file tree (Contents tab), a data view (Preview tab), and a metadata document (Metadata tab).
(6) Highlight the layer for the Counties shapefile and click on the Preview tab in the right panel. First look at the Geography preview.
You can see the layer represents the outline of Texas. The preview option allows one to display the feature class table as well, by selecting Table instead of geography at the bottom of the panel.
If you click on the Metadata tab, you’ll see descriptive information about the Counties layer:
Click on the other two data layers to preview them also.
2. Creating Geodatabases, Feature Datasets, and Feature Classes
A geodatabase is a relational database that stores geographic information. In turn, a relational database is a collection of tables logically associated to each other by common key attributes. A geodatabase can store geographic information because, besides storing a number or a string in an attribute column, tables in a geodatabase can store a geometric object (i.e., polygon, line or point) with defined shape and location. A personal geodatabase consists of a file with extension .mdb
A feature dataset is a collection of feature classes that share the same spatial reference. The spatial reference describes both the projection and spatial domain extent for a feature class in the geodatabase. Because the feature classes in a feature dataset share the same spatial reference, they can participate in topological relationships with each other such as in a geometric network. These topological relationships can also be stored in the feature dataset. Note that feature classes in a geodatabase can exist as stand-alone feature classes, without being part of any feature dataset.
A feature class is a collection of features with similar geometry. There are point, line, and polygon feature classes. Two types of feature classes exist: simple feature classes and topological feature classes. A simple feature class includes features that have no topological associations among them and features maybe edited independently of each other. Topological feature classes are bond as one integrated topological unit.
Create a new Geodatabase
(1) To create a new geodatabase in Arc Catalog first right click on the folder that contains the data for the exercise. Select New/Personal Geodatabase and a new geodatabase -- called New Personal Geodatabase.mdb and represented by an icon with the shape of a cylinder -- will be created,
and (2) overwrite the name of the geodatabase with Ex1Data (the geodatabase will keep its file extension mdb regardless of whether you included it in the name or not). You can right click on the geodatabase name and use Rename to rename the file if necessary.
Adding Data to the Geodatabase
When first loading data into a geodatabase, it is important to think about the data and how they are related. As mentioned above, in geodatabases the data is placed in feature classes that are then organized into feature datasets. A geodatabase can have one or more feature datasets. Each feature dataset has a single reference frame, which includes the map projection and map extent. It is possible to define the reference frame after the creation of the feature dataset and before data is loaded. There is a simpler method to be certain that your entire data will be completely contained in a feature dataset. When you load data into a feature dataset, the first feature loaded dictates the reference frame of the dataset. Therefore, you simply load the shapefile or coverage, which covers the largest extent, and all your data will be in the correct reference frame.
To add data to the Ex1Data geodatabase within a feature dataset, in ArcCatalog: (3) right-click on the name or icon of Ex1Data, select Import/Shapefile to Geodatabase, browse for the shapefile Texas and click to convert it. Type the name Texas into the window below the “Select an existing feature dataset or enter a new one” to create the new feature dataset Texas.
Click Ok and a new feature dataset called Texas will be created within the Ex1Data geodatabase, and within that a new feature class called Texas will exist which contains the outline of the state of Texas.
We have actually done something rather clever here, which is that we have defined a spatial reference frame for the feature dataset Texas by importing an outline of the state boundary with an existing map projection. The outline of the state establishes the required map extent needed to cover data within the state of Texas, and the map projection information defines the coordinate system by which data will be mapped within this outline. If you right click on the feature dataset and go to Properties, you’ll see what a map projection is used for these data.
Import the other shape files for Counties and Evaporation to the feature dataset in a similar way that you just did for the Texas outline. Right-click on the name or icon of Ex1Data, select Import/Shapefile to Geodatabase, browse for the shapefile Counties and click Open, Click Next to get the destination screen. Select the existing output feature dataset Texas, and name the new feature class counties:
and click Ok, and Counties will be added to the Texas feature dataset.
Repeat the process for the shapefile Evap, but in this case name the new feature class Evap, and click Ok. The shapefiles Counties and Evap have been added to the Texas feature dataset as feature classes.
After creating the geodatabase, the feature dataset and the feature classes, the ArcCatalog tree looks like this:
Note that the feature classes Texas, Counties, and Evap could have been created outside the feature dataset Texas, but since they share the same spatial reference, it was decided to group them together within the feature dataset. Trying to import spatial data to an existing feature dataset may cause a conflict between different spatial reference frames. This is very likely to occur when attempting to import data to an empty feature dataset created without defining its spatial reference.
3. Displaying Feature Datasets in a Map
We will now add the feature dataset that we created in ArcCatalog to an ArcMap document. To display the spatial data of the Texas feature dataset in a map, first open ArcMap.
(1) You can launch ArcMap from within ArcCatalog:
or you can open ArcMap from the Start menu as you did before. Click on
the Add Data button, 
.
(2) Browse to the feature dataset Texas, 
and click Add.
This has the effect of adding all the feature classes in the feature dataset to
the ArcMap display. You can add individual feature classes within the
Texas feature dataset if you so desire, by clicking on the feature dataset
icon, and then on the icons of one or more of the feature classes (Hold down
Ctrl or Shift to select more than one feature class).
Note that the Table of contents lists the layers corresponding to the three feature classes of the Texas feature dataset that you just added, while the Display window displays the map with the corresponding spatial data (i.e., Texas counties and evaporation stations).
(3) Save your work in ArcMap by choosing File/Save and, after navigating to your working directory, writing the file name Ex1 (the file will be assigned the extension mxd).
(4) To change the appearance of a map display, you can access the Symbology menu just by double clicking on the Symbol displayed in the ArcMap Layer Table of Contents.
Click on the symbol color box, make your selections for the Fill Color and the Outline Color, and click OK, twice. Follow this procedure to modify the display of the Evap layer. Hopefully, the new map looks better than the original one.
More complicated symbol shading that has the color and size of the symbols varying according to attributes of a feature class, can be manipulated by accessing the Symbology tab of the Properties of the Feature Class.
4. Accessing and Querying Attribute Data
Numerical and text information stored in the fields of the geodatabase tables are called attributes. To access attribute data of the feature classes at a specific location, in ArcMap: make visible the layers Evap and Counties (assuming you want to retrieve information of both layers) by clicking on Evap and then holding down the shift key select the Counties file.
(1) Click on the Identify Features tool 
which is contained within the
“Tools” menu. If you
don’t see this set of tools on your ArcMap document, use View/Toolbars
and click on Tools to make it appear.
(2) Click on the location on the map you are interested in, and in the Identify Results window, select the object you are interested in. In the figure, attribute data for the Austin Airport evaporation station and Travis County has been retrieved
If you inadvertently close the Tools menu you just used, you can open it again from the View menu:
Viewing an Attribute Table
(3) To access attribute data of an entire layer, in ArcMap: right click on the Evap layer name in the table of contents, and select Open Attribute Table:
Tables that contain attribute data of a layer are always called Attributes of <layer name>, and contain a field called Shape. The field Shape displays the words Point, Line or Polygon, but it really stores a geometric object with the shape of a point, line or polygon.
Note that record number 44 (indicated by the arrow in the table) corresponds to Austin evaporation station. All attribute data is the same as retrieved before, except for the Shape field, but that does not mean that the table stores information different from what can be retrieved with the Identify Features tool. You can see from the blue dot on the map, the geographic location of the Austin Airport where these pan evaporation data were measured.
(4) To Clear a Selected feature and select a new one, use: Selection/Clear Selected Features in the ArcMap toolbar:
5. Selecting Objects of a Geodatabase Table (points, lines and polygons)
Selecting objects of a geodatabase table refers to tag a subset of the objects of the geodatabase table for a specific purpose. Object selection can be made from a map by identifying the geometric shape, or from an attribute table by identifying the record. Regardless of how you select an object, both the shape in the map and the record in the attribute table will be selected. To choose a particular data layer for selection use Selection/Set Selectable Layers and then click off the layers that you don’t want to have selected.
(1) To
select an object from the map, in ArcMap: click on the Select Features
tool 
, in the
Tools menu
(2) Click on the Counties polygons you want to select. To select more than one object, press the Shift key and hold it down while you click on the additional objects. Selected objects are displayed with a light blue outline, although the color might change depending on your settings. The corresponding attribute table records have also been selected. You can verify this by opening the Counties attribute table.
(3) To clear your selection, right click on the layer name, and choose Selection/Clear Selected Features.
(4) To select an object from the attribute table, in ArcMap: (a) in the table of contents, click on the layer name Counties, (b) select Open Attribute Table, (c) in the Attribute Table, click on the square at the left of the records you want to select. To select more than one record, press the Ctrl key and hold it down while you click on the additional records. Selected records are displayed with a light blue background, although the color might change depending on your settings. The corresponding objects in the map have also been selected. You can verify this by returning to the map window.
To clear your selection, click on the Options button of the attribute table window, and choose Clear Selection.
6. Making a Chart
Charts are useful because they allow you to visualize trends in data. ArcMap has chart-making capabilities. We will plot a chart of one or more records selected from a geodatabase table.
(1) Use Selection/Set Selectable layers to show only the Evap data layer.
Select the two evaporation points that are located in Travis County.
To create a chart, choose Tools/Graphs/Create, this opens the Graph Wizard.
(2) You will be making a Column chart so just click on the Next button. The next screen will allow you to indicate the data to be used in the graph. The layer or table you will use is the evap layer. Keep the Use selected set of features or records selected.
(3) Toggle the Fields button next to the phrase Graph data series using the scroll bar on the right hand side of the attribute names. Now you will select the data to be graphed. We will make a graph comparing the evaporation at the stations selected for each month of the year (Jan_Val to Dec_Val). The values shown are the mean monthly pan evaporation in inches.
(4) Choose the monthly values to graph by selected them. Hit the Radio button for Graph data series using “Fields”. Click the Next button.
In the final step of the Graph Wizard you will specify the chart title and other presentation specifics. (5) Give the chart the title Pan Evaporation and label the legend with the attribute STAT_NAME. Play with the Bar gap to change the size of the bar.
Press Finish. You have created a graph in ArcMap!!
Another option is to make a chart in Excel using the dBase tables given by the evaporation shapefile. Open the evaporation attributes table evap.dbf as a table in Excel. Use Files of Type: dBase files in Excel to focus only on .dbf tables when you open the table. Select the stations you want to plot, copy their records to a new worksheet, delete the columns you don't need there, and then create a chart. Here is an example chart created this way. The column headers have been renamed from Jan_Val to Jan, etc to make the Chart x-axis more attractive to view. The legend has been moved to the top of the chart to allow a wider spacing of the data in the chart.
7. Consolidating Your Results for Presentation
To consolidate a map of counties of Texas with evaporation stations with the graph that you created before in a single sheet of paper, in ArcMap: (1) change the format of the display window from Data View to Layout View by clicking on View/Layout View,
Reduce the size of the data frame (i.e., rectangle where the spatial data is contained) -- to make room for the graph -- by clicking on the graph and moving its handlers. If you have a zoomed in view in Arc Map, you’ll get the same image in in the Layout. To go back to the image of the whole State of Texas, right click on the Texas data layer in the legend and select Zoom to Layer. To insert the Chart into the Layout, right-click on upper blue bar at the top of the Chart and select Show on Layout. Move and resize the graph as necessary. You can draw lines to relate the location of the measurement stations and the data plotted on the graph using the Draw a Line tool from the ArcMap Draw toolbar (to display this Toolbar, use View/Toolbars and select Draw).
Or you can add text with the text tool 
shown next
to the line draw tool. You can also insert a North Arrow by using
the Insert menu in ArcMap.
Your final map could look like this:
You can print this map directly from ArcMap, or you can copy it into Word and print it from there. To copy a map into Word, Right Click on the map in the ArcMap Layout, and you'll see an option Copy Map to Clipboard. When you open Word, use the option Edit/Paste Special and you'll get a Window that allows for an ESRI ArcMap Document Object. If you hit OK here, then your map will paste right into Word as it looks in ArcMap!
Here's another option: suppose you want to take a chart in Excel and add a map to the Chart to show where the data apply. If you Copy the Map to the Clipboard in ArcMap, you can Paste it in Excel and annotation to connect the map to the Charted data:
The manipulations just described transfer objects from one application to another. A more general procedure is to simply copy the screen to the clipboard and cut out the part that you want, saving it to a file for later use. That is how all the images in this exercise were prepared. To copy any image, hit Shift/Print Screen on your keyboard (this copies the Screen onto the Clipboard). From the Start Menu in Windows, Open Accessories/Paint.
Use Edit/Paste to paste the contents of the Clipboard into Paint. You'll now see an image of all the things on your original computer screen. Click on the open box under Edit so that the cursor becomes a cross and use it to draw a dashed box around the portion of the image that you want to keep.
Use Edit/Copy To to save the file as a .bmp bitmap file. Then in Word, you can use Insert/Picture/From File to insert the .bmp file into Word. Note that in ArcMap you can use Insert/Picture to similarly insert pictures into your maps!! Very cool!
8. Do Something Creative
Now that you are familiar with the operation of ArcGIS 8.1, make some new maps in places that are of interest to you. Some additional data showing precipitation, temperature, and net radiation values for the whole world on a 0.5° mesh, can be found in http://www.ce.utexas.edu/prof/maidment/giswr2002/ex12002/txclim.zip, or in the Climate folder in the same place in the LRC class folder from which the original data for this exercise were obtained.
To Be Turned In: A completed map and chart of selected data.
These materials
may be used for research and educational purposes only. Please credit the
authors and the
Center for Research in Water Resources at The University of Texas at Austin.
All commercial rights reserved. Copyright 2002 Center for Research in Water Resources.