Using ARC/INFO on Strauss



ARC/INFO is Geographic Information System (GIS) software developed by Environmental Systems Research Institute (ESRI). It is a full-featured package with tools for automation, analysis, display and management of geographic information. Typical applications include land resource management, automated mapping and facilities management, demographic analysis, forestry, environmental analysis, water resource management, mineral exploration, transportation, and telecommunication. Federal agencies such as the U.S. Geological Survey, Environmental Protection Agency, and the Natural Resource Conservation Services have adopted ARC/INFO as their GIS standard. Furthermore, many universities teach GIS using ARC/INFO. Consequently ARC/INFO has a large established user base in the GIS community and ARC/INFO-formatted spatial data is readily available from federal, regional, and state agencies as well as commercial data providers.

This documentation introduces the use of the ARC/INFO software installed on Strauss. First-time users should read the introductory book Understanding GIS - The ARC/INFO Method. This book describes the vocabulary and basic concepts of GIS as implemented in ARC/INFO.

ArcView, a simpler-to-use GIS product from ESRI, is also installed on Strauss. ArcView has many tools to perform spatial data presentation and analysis. Research Data Management Services staff can help you decide which package is more appropriate for your needs.

You can obtain ARC/INFO and ArcView for installation on a University-owned system (UNIX, PC, or Macintosh) at a nominal or no charge through the University site license. For details, send mail to

Using ARC/INFO on Strauss: Contents

How to run ARC/INFO

ARC/INFO can only be run on Strauss. It is not installed on the other central UNIX systems. Furthermore, you must be on an X terminal or running an X-server on an IBM clone or a Macintosh. (For Windows based PCs xMing is recommended. For Macintoshes, we recommend MacX.)

Proper use of ARC/INFO requires you to assign values to a few UNIX environment variables and to erase temporary files that ARC/INFO leaves in /tmp after ARC/INFO terminates. The easiest way to run the program and do these tasks automatically is to type the following command at a UNIX prompt:


While running ARC/INFO, the prompt becomes
Using ARC/INFO on Strauss: Contents
Important recommendations on case sensitivity

All subsystems of ARC/INFO except the tabular database management subsystem INFO are generally case-insensitive. However, all externally created UNIX filenames as well as commands in the INFO subsystem are case-sensitive. We recommend that you type all commands in ARC/INFO in upper-case letters (except for UNIX filenames). Furthermore, when you define new objects (files or attribute names) in ARC/INFO, you also should use upper-case letters.

Files and directories created outside of ARC/INFO need special attention. The full pathname of the file must be in lowercase. When typing an external filename in an ARC/INFO command, type the name in lowercase.

If you choose not to follow these guidelines, you should consult the additional details on case sensitivity at the end of this document.

Using ARC/INFO on Strauss: Contents

Running the ARC/INFO tutorial

Before starting, you should close other graphics-intensive applications. For example, if you are running Netscape, quit the program before continuing; minimizing the program is not sufficient. This will eliminate color-table conflicts between those applications and ARC/INFO.

  1. Start the ARC/INFO tutorial.

    1. At the UNIX prompt, start ARC/INFO by typing
    2. At Arc: prompt, type
           Arc: &run $SAMPLESHOME/tutorial/tools/tutorial 
      The UNIX environment variable SAMPLESHOME is defined in the ARC/INFO startup script. It may take a while to start the tutorial session, based on Strauss' load. After the 'ARCPLOT' window appears, resize and rearrange your windows so you can see your Strauss xterm, 'ARC/INFO Tutorial', and 'ARCPLOT' windows at the same time.

    3. An abbreviated guide to the tutorial.

      This section guides you though the 'Map Display and Query' part of the tutorial. Select menu items by using your left mouse-button to click on the item, unless directed otherwise.

      1. In the main menu, click on 'Learn' Map Display and Query.

      2. Read the text in the 'Map Display and Query (1)' window and click on 'Continue...'.

      3. After reading the 'Map Display and Query (2)' window's text, click on 'Display'. A map of ESRI Redlands appears in the display window. In addition, the messages you would get when you run an actual ARC/INFO session appear in Strauss' xterm window.

      4. After the display process is finished, click on 'Continue...' in the 'Map Display and Query (2)' window.

      5. Read the text in the 'Map Display and Query (3)' window. In this step, you will experiment with defining and displaying different areas of interest ('extents'). Click on 'Pan/Zoom' in the 'ARCPLOT' window with the right mouse-button. Then select 'Extent' in the 'Pan/Zoom' pull-down menu. The arrow cursor becomes crosshairs. Use the left mouse-button to define a rectangular extent by clicking a small area's opposite corners. (The area's boundaries will become outlined by a light green box.) After experimenting, you may return to the original view by selecting 'Fullview' from the 'Pan/Zoom' pull-down menu. You may create additional display windows for side-by-side comparisons by selecting 'Create' and marking an 'extent', as above.. After you finish experimenting with the Pan/Zoom tools, click on 'Continue...' in the 'Map Display and Query (3)' window.

      6. In the 'Map Display and Query (4)' window, click on 'Identify Polygons', move the mouse pointer into the 'ARCPLOT' window. The arrow cursor becomes crosshairs. To obtain information about a particular polygon, click the left mouse-button over that polygon you want to identify. Click on 'Quit' after you finish reading the contents of the pop-up text window.

      7. In the 'Map Display and Query (4)' window, click on 'Distance' and move the mouse pointer into the 'ARCPLOT' window. You will use the left mouse-button to define a route whose distance you want to measure. Click on as many intermediate points as you want. Hold the Control key while pressing the right mouse-button to end your route definition. The distances are displayed in the Strauss xterm window, measured both in page units and actual map units. In the sample map, the page unit is inches and the map unit is feet.

      8. In the 'Map Display and Query (4)' window, click on 'Continue...'. The 'ARCPLOT' window's contents will be erased.

      9. In the 'Map Display and Query (5)' window, read the text and click on 'Shade graph'. ARCPLOT will display a sample of a stacked, shaded line graph.

      10. You may optionally learn about other ARC/INFO topics such as 'ARC/INFO Data Sets' and 'Creating and Editing Coverages' by selecting 'Main menu...' in the 'Map Display and Query (5)' window.

      11. Click on 'QUIT' to end the tutorial session. The Arc: prompt will reappear in your Strauss xterm window.

      12. Type 'QUIT' at the Arc: prompt to exit from ARC/INFO entirely.
    Using ARC/INFO on Strauss: Contents

    Overview of the ARC/INFO software system

    ARC/INFO is composed of 7 major subsystems:

    To start a subsystem, type its name at the ARC/INFO prompt Arc:. For example,
         Arc: ARCEDIT
    launches an ARCEDIT session and changes the prompt to Arcedit:. Type 'QUIT' at the Arcedit: prompt to exit from the ARCEDIT subsystem.

    In addition, ARC/INFO has several application-specific extensions for network analysis and design, volumetric analysis, corridor analysis, cadastral basemap creation, etc.

    Using ARC/INFO on Strauss: Contents

    Quick tour of ARC/INFO subsystems using command line input

    In this quick tour, you will enter the ARC, ARCEDIT, ARCPLOT and INFO subsystems and execute commands in each system to become familiar with the ARC/INFO command syntax. All text appearing after '/*' are comments and are not part of the command. Do not type the comment sections.

    1. Initial preparation: Set up a workspace for an ARC/INFO session and obtain sample data

      1. Check your disk quota to make sure you have at least 600 Kbytes of free disk space. At the UNIX prompt, type
             quota  -v
        Make a subdirectory called 'arctest' to contain the sample data and newly created ARC coverages. Be sure to type 'arctest' in lower-case letters. Make 'arctest' your current working directory.
             mkdir arctest
             cd arctest
        Before starting, you should close other graphics-intensive applications, such as Netscape. This will minimize color-table conflicts between those applications and ARC/INFO.

      2. At the UNIX prompt, start ARC/INFO by typing
      3. Make the current directory an ARC/INFO workspace by typing the CREATEWORKSPACE command at the Arc: prompt:
             Arc: CREATEWORKSPACE .  /* Trailing '.' refers to current directory
      4. Copy the ARC/INFO 'GRID' named WASHDC_SUB from the sample workspace into the current workspace. In general, a 'GRID' is an ARC/INFO raster image. This GRID is a small portion of a SPOT satellite image that includes the White House in Washington, DC.
             Arc: COPY  /hsm/users/dsacher/jianchen/arcsample/quicktour/WASHDC_SUB  WASHDC_SUB
      5. Copy a TIFF-formatted graphic image of the same region from the ARC/INFO sample directory. The image will be used in the digitizing exercise below. UNIX commands such as 'cp' may be issued at the Arc: prompt. The command is passed to your UNIX shell for processing and control is returned to ARC/INFO.
             Arc: cp  /hsm/users/dsacher/jianchen/arcsample/quicktour/example.tif  example.tif
      6. Start the UNIX 'xv' graphics viewer as a separate window to display the 'example.tif' file. The image will help you locate the positions of 'tics' and street lines used in the next section. 'Tics' are the reference points associated with known coordinates on a map and are used to orient the map.
             Arc: xv example.tif &
      7. Specify X Windows as the display environment by typing
             Arcedit: DISPLAY 9999 
        When the 'ARCEDIT' window appears, rearrange the windows so you can see the 'ARCEDIT', 'example.tif', and Strauss xterm windows at the same time.

    2. Digitize street segments based on the satellite image using the ARCEDIT subsystem.

      In this section, you will use labeling information found on the xv-displayed map to identify the locations of six streets on the ARCEDIT-displayed map.

      1. Make the Strauss xterm window active by clicking anywhere in it. Then enter the ARCEDIT subsystem by typing its name at the Arc: prompt
             Arc: ARCEDIT
      2. Set the SPOT satellite image WASHDC_SUB as a background image in the 'ARCEDIT' display. Specify that the limits of the display are those defined by the ARC/INFO GRID named WASHDC_SUB coverage.
             Arcedit: MAPEXTENT WASHDC_SUB    /*Specify map extent's GRID name
             Arcedit: IMAGE WASHDC_SUB        /*Specify SPOT image as background
             Arcedit: DRAWENVIRONMENT ARC TIC /*Display arcs and tics 
             Arcedit: DRAW                    /*Display the image  
      3. Create a new coverage called WASHDC_COV

      4. Arcedit: CREATE WASHDC_COV

      5. In order to digitize in the ARCEDIT window, you must first establish some base points - the 'tics' - in order to tie the map to the real world coordinate system. For this demonstration, accuracy is not critical. Therefore, you only need to get the approximate positions for these tics.

        In the Strauss xterm window, type 11 as the first Tic-ID; and press the Return key. Then move the cursor into the 'ARCEDIT' display window. The cursor will become crosshairs. Click the left mouse-button near the lower-left corner of the image at the position shown by the black square marker in xv's 'example.tif' window. Repeat the process to add three more tics in the 'ARCEDIT' window at the corner positions shown in the 'example.tif' window and having Tic-IDs equal to 12, 13, 14, respectively.

        After digitizing the four tics, click the cursor at the Tic-ID prompt, and press the Return key. ARCEDIT will prompt you to define an initial boundary. Use the cursor to define a boundary box that is slightly larger than the image by clicking at opposite corners of the boundary box.

        This makes 'WASHDC_COV' the current edit coverage.

      6. Use the DRAW command to cause the four tic marks to be displayed along with the images.
             Arcedit:  DRAW

      7. Add streets (arcs) into the current edit coverage
             Arcedit: EDITFEATURE ARC   /* Arc is the 'feature' you want to add
             Arcedit: ADD               /* Begin a session to add arcs

        Look in the Strauss xterm window to see the nine options currently available. You can select those options by pressing the mouse-buttons alone or together with the Shift key or Control key. The following table shows the association between the option and the corresponding keyboard and mouse action for a three-button mouse. (If you are using a two-button mouse, clicking the two buttons at the same time is equivalent to clicking the middle button on a three-button mouse.)

        Option NumberKeyboard and Mouse Action
        1left mouse-button
        2middle mouse-button
        3right mouse-button
        4Shift key + left mouse-button
        5Shift key + middle mouse-button
        6Shift key + right mouse-button
        7Control key + left mouse-button
        8Control key + middle mouse-button
        9Control key + right mouse-button

        Move the cursor into the 'ARCEDIT' display window. Select option '8) Digitizing Options' by holding down the Control key and pressing the middle mouse-button. The 'DIGITIZING OPTIONS' message appears in the Strauss xterm window.

      8. Begin digitizing the first street by first selecting digitizing option '1) New User-ID'. Do this by clicking the left mouse-button in the 'ARCEDIT' display window. Enter the value 101 at the 'New User-ID: :' prompt in Strauss' xterm window .

        In this part, you will trace the streets in the 'ARCEDIT' window by marking the start point, any intermediate points you want, and then the final point. First move the cursor into the 'ARCEDIT' display window. Trace the street that is identified by the line labeled 101 in the 'example.tif' window. Be sure to do the tracing in the 'ARCEDIT' window.

        Start a street by positioning the pointer at one end of the street. Press the middle mouse-button (to identify that point as a node). Add intermediate points (vertices) by clicking the left mouse-button. When you're pointing to the other end of the street, click the middle mouse-button to signify that you're identifying a node.

        Should you make any mistakes during the tracing process, you can stop the digitizing process by holding down the Control key and pressing the right mouse-button in the 'ARCEDIT' window. Then issue the following commands at the 'Arcedit:' prompt to restart the tracing process.

             Arcedit:  DELETE             /* Delete all the tracing work
             Arcedit:  SAVE
             Arcedit:  EDIT  WASHDC_COV   /* Specify current edit coverage
             Arcedit:  IMAGE  WASHDC_SUB  
             Arcedit:  DRAW               /* Redisplay the image
        and return to step g, above.

      9. Use above procedures to add lines identified with IDs 102, 103, 104, 105 and 106 in the 'example.tif' window. Remember to use the middle mouse-button to mark the beginning and end of each street. Use the left mouse-button only for intermediate points.

      10. Stop the digitizing process by holding down the Control key and pressing the right-mouse-button in the 'ARCEDIT' window. This corresponds to Digitizing Option 9.

      11. Save the new coverage WASHDC_COV
             Arcedit: SAVE
      12. Exit the ARCEDIT subsystem.
             Arcedit: QUIT

    3. Build a topology for the 'WASHDC_COV' coverage.

      1. Build a topology for the WASHDC_COV coverage using the 'line' option.
             Arc: BUILD  WASHDC_COV  LINE  

      2. Examine the elements in the 'Arc Attribute Table' for the WASHDC_COV coverage
             Arc: ITEMS WASHDC_COV.AAT   /* List items in the arc attribute table

        Here is a brief description of the items in the attribute table.

        FNODE#From (or starting) node number
        TNODE# To (or ending) node number
        LPOLY# Left polygon number
        RPOLY#Right polygon number
        LENGTHLength of the arc
        WASHDC_COV#ARC/INFO internal number
        WASHDC_COV-IDID number you supplied when digitizing.

      3. List the values of the items in the Arc Attribute Table. In the output, the LPOLY# and RPOLY# values are all zero because there is no polygon topology in this coverage.
             Arc: LIST WASHDC_COV.AAT	

    4. Add street names into an INFO subsystem table

      1. Use an editor to create a file containing the street ID values and their corresponding names. Name the file 'washdc.txt'. For example, you might type
             Arc: pico washdc.txt
        and save the file after entering the following information:
             101,New Hampshire Ave
             102,Rhode Island Ave
             103,New York Ave
             104,Pennsylvania Ave
             105,Pennsylvania Ave
             106,Massachusetts Ave

      2. Start the INFO subsystem by typing 'INFO' at the Arc: prompt. When prompted for the USER NAME, enter 'ARC'.
             Arc: INFO
             ENTER USER NAME > ARC

      3. Define a new INFO file named 'WASHDC.DAT' that will contain two fields: The first field 'WASHDC_COV-ID' will have the same name as the street identification field in the Arc Attribute Table created above. The second field 'AVE_NAME' will identify the street name. After defining the field names, import the actual data from the file 'washdc.txt'. The actual commands appear below, followed by comments on each line.
             ENTER COMMAND > DEFINE WASHDC.DAT  /* Define a new INFO file
             ITEM NAME > WASHDC_COV-ID          /* First field: WASHDC_COV-ID
             ITEM WIDTH > 4	 
             ITEM OUTPUT WIDTH > 5
             ITEM TYPE > B                      /* 'B'=Binary item type
             ITEM NAME > AVE_NAME               /* Second field: AVE_NAME
             ITEM WIDTH > 40
             ITEM OUTPUT WIDTH > 50
             ITEM TYPE > C                      /* 'C'=Character item type
             ITEM NAME >                        /* Press Return key to stop
             ENTER COMMAND > ADD FROM ../washdc.txt /* Import the data from the text file
             6 RECORD(S) ADDED

        In some cases, the text file's full pathname must be typed rather than the shortened '../washdc.txt' form.

              ENTER COMMAND > LIST              /* List the INFO file contents
              1          101          New Hampshire Ave
              2          102          Rhode Island Ave
              3          103          New York Ave
              4          104          Pennsylvania Ave
              5          105          Pennsylvania Ave
              6          106          Massachusetts Ave

      4. Quit the INFO subsystem by typing
             ENTER COMMAND > Q STOP             /* End the INFO session

    5. Add the street name information from the INFO file to the Arc Attribute Table.

      1. The JOINITEM command joins the attribute table of the coverage WASHDC_COV with the INFO file WASHDC.DAT according to the common item named WASHDC_COV-ID. This allows you to attach the names of the streets (item AVE_NAME) to the Arc Attribute Table. To see the format of the command, type 'USAGE JOINITEM' at the Arc: prompt. To attach the names, type the following command as one line at the Arc: prompt:
                                 WASHDC_COV-ID    WASHDC_COV-ID
      2. Type the LIST command to examine the new contents of the Arc Attribute Table. Notice that the 'AVE_NAME' item has been added.
             Arc: LIST WASHDC_COV.AAT

    6. Use the ARCPLOT subsystem to display the resulting coverage

      1. Type 'ARCPLOT' at the Arc: prompt to start the ARCPLOT session. The 'ARCPLOT' window may take a while to open, depending on the system load.

      2. Display the SPOT image by typing the following commands in the Strauss xterm window. The commands define the region of interest to be the extent of the GRID named WASHDC_SUB.

             Arcplot: MAPEXTENT  WASHDC_SUB
             Arcplot: IMAGE  WASHDC_SUB    /* Display the image

      3. Plot the streets you just digitized in the ARCEDIT session by typing the following commands. The 'ARCTEXT' command instructs the system to label the arcs (streets) with the values of the item 'AVE-NAMES' from the Arc Attribute Table. The '#' signifies that you want to use the default value for the third argument of the ARCTEXT command.
             Arcplot: LINESET  CARTO.LIN   /* Use the 'carto.lin' line set 
             Arcplot: LINESYMBOL  203      /* Use line symbol 203 for the streets
             Arcplot: ARCS  WASHDC_COV     /* Display the streets (arcs) 

        Arcplot: TEXTSET FONT /* Select the FONT text set Arcplot: TEXTSIZE 0.2 /* Specify the text size Arcplot: TEXTCOLOR RED /* Specify the text color


      4. Quit ARCPLOT session by typing 'QUIT'. This closes the 'ARCPLOT' window and returns you to the Arc: prompt in the Strauss xterm window.
             Arcplot: QUIT

    7. Create a 100-meter buffer area around these streets

      1. Create the buffer zone using the ARC command 'BUFFER'. You can type 'USAGE BUFFER' to see the form of the complete command. In this example, you will use '#' to indicate that you want the default values for the fourth and sixth arguments of BUFFER. The command uses WASH_COV as the input coverage, WASH_BUFF as the output coverage, AVE_NAME as the item whose non-missing values indicate which arcs (streets) are to be buffered. It specifies that you want a round shape buffer at the end of each street section. Type the following as a single line at the Arc: prompt.
                            #  100  #  LINE  ROUND  FULL

      2. Display the buffer zone coverage 'WASHDC_BUFF' in ARCPLOT by starting the ARCPLOT subsystem and issuing four ARCPLOT commands:
             Arc: ARCPLOT
             Arcplot: MAPEXTENT  WASHDC_SUB
             Arcplot: IMAGE  WASHDC_SUB
             Arcplot: LINECOLOR  RED
             Arcplot: POLYS  WASHDC_BUFF /*Display polygons in the buffer coverage

      3. Quit the ARCPLOT subsystem by typing 'QUIT' at the Arcplot: prompt and exit from ARC/INFO by typing 'QUIT at the Arc: prompt.
             Arcplot: QUIT
             Arc: QUIT
    Using ARC/INFO on Strauss: Contents

    More details on case sensitivity

    If you are following the recommendations on case sensitivity given above, you can skip this section.

    There are five key rules that govern the way ARC/INFO deals with uppercase and lowercase commands.

    1. UNIX directories in which you do ARC/INFO work must not have uppercase letters in the full directory name.

    2. The INFO subsystem is case-sensitive. Therefore, if you define the INFO item 'ave_name', that produces a different result than if you had defined the item 'AVE_NAME'.

    3. The ARC, ARCPLOT, and other subsystems assume that INFO file names and item names are uppercase only, regardless of whether you originally defined them in uppercase or lowercase. For example, the ARCPLOT command 'arctext washdc_cov ave_names # line' will not work if you originally defined the INFO item as 'ave_name'. That's because ARCPLOT immediately translates the second argument to 'AVE_NAME' since it's an INFO item.

    4. Aside from the INFO file and item name uppercase translation, all other ARC/INFO commands may be typed in uppercase or lowercase.
    Using ARC/INFO on Strauss: Contents

    For more information

    The ARC/INFO on-line help system is very complete. At the Arc: prompt, type 'HELP'

         Arc: help

    This opens a 'ARC/INFO Help' window. It may take a while for these windows to appear, depending on the load on Strauss. The 'ARC/INFO Help' window provides an introduction to ARC/INFO in the "ARC/INFO Concepts" section. All the commands in its subsystems are listed in the "Command reference for ARC/INFO prompts" section. Within the "Command reference for ARC/INFO prompts" section, there are functional and alphabetical list of the commands in each subsystem.

    There is a set of ARC/INFO manuals in the RDMS Data Center, accessible through 002 Smith Hall. In addition to the manuals on each subsystem, we highly recommend the introductory manual Understanding GIS - The ARC/INFO Method (UNIX version). These are all non-circulating reference materials for use only in the Data Center. Please register in 015 Smith Hall to use the Data Center. You can also purchase copies of these manuals directly from ESRI .

    The Environmental Systems Research Institute (ESRI) WWW server has descriptions of many ARC/INFO-related publications as well as the text contents of ESRI's quarterly newsletter ARC News.

    You may also contact User Services for assistance with specific ARC/INFO problems.

    Using ARC/INFO on Strauss: Contents

    Last modified: May 27, 2009.
    This page maintained by Ben Mearns.
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