GEOG 474

Introduction to Computing and Image Processing Software
Exercise 1

2 corrections shown below in red

    This exercise is designed to familiarize you with the computers and image processing software systems we will be using this semester.  The exercise is broken into two main parts.  The first portion of the exercise discusses the various computers we will be working on and the specific class accounts and additional disk space that have been allocated.  The two image processing systems we will be using heavily during the semester are covered in the second section of the exercise.

Part 1.  Introduction to Computing

    During this course we will be using several image processing packages;  two of the packages are ArcView and McIDAS.  Just as a brief overview, the following image processing systems, the platform they are found on and the computing sites where you can assess the software are listed below.

Software Platform Computing Sites
 ArcView 3.1 Central system (strauss) 

PCs (Windows 98 and NT)

Pearson Hall Training Center (Xterm lab - Room 114) 

Pearson Hall Training Center (PC lab - Room 116); RDMS Data Center (Smith Hall Room 002C)

 ArcView Image Analysis1.0 PCs (Windows 98 and NT) only Pearson Hall Training Center (PC lab - Room 116); RDMS Data Center (Smith Hall Room 002C) 
 McIDAS 7.6 Geography SGI server (davinci.geog) only Pearson Hall Training Center (Xterm lab - Room 114) 

Central System (strauss)

    On the central computing system (strauss) Geography 474 has been assigned a class project number of 2053.  Whenever you are working on strauss for this course, make sure you are using the 2053 class project rather than your default project of 4000 (email) which has limited funds.  Additional disk space will be allocated above your 4 Mbytes (usrc) on your home directory (/home/base/usrb/geog474/your_username).  The instructor will let you know when this space has been setup.

    Become familiar with the central systems essential unix commands by  reviewing the Unixhandout given out in class.  You can also find this handout called under the ~hanson/Geog250/ps directory on Strauss. Pay particular attention to how you find out what project accounts you belong to, how you change your default project, and how much space you have in use and available.

    Throughout the semester, you may need to use an Editor. If you are already familiar with an editor on the central system, great!  However, if you are not, the Instructor suggests you learn Emacs/XEmacs.  Review the handout given in class or found online under the  ~hanson/Geog250/ps directory. A tutorial,, located on Strauss under the same directory will help familiarize you with Emacs/Xemacs.

Geography SGI Server

    Accounts have also been setup to use McIDAS on Geography's SGI Server called  The Instructor will let you know your username and password.  To access the Server and run McIDAS follow the instructions below.

Logon to Copland or Strauss

copland% ssh davinci.geog

enter password
davinci% mcidas &
& - returns your prompt
Pearson Hall Training Center PCs

    ArcView's Image Analysis is located on all the IBM-Compatible PCs in the Training Center (Room 116).  You will need to FTP data files from the Instructor's class directory on Strauss to local Geog474 folder.

Instructor's class directory is located on strauss at /home/base/usrb/tracyd/Geog474 and particular files for each exercise are found under the exercise directory.
A Geog474 Folder has been set up on each PC in the Training Center for temporary use and storage as you work through the exercises.   You can find the Folder by:
  • Open My Computer from the desktop (upper-left corner of screen)
  • Open the C:\ drive from My Computer
  • Open the Geog474 folder from C:\
  • The local class Folder is not secure, so FTP from C:\Geog474 to Strauss all files you wish to save before you quit .

    Using FTP to Transfer Files Between Strauss and a PC at MS-DOS Window

    FTP stands for File Transfer Protocol, and it allows you to move a file between machines (Strauss to Davinci) or across platforms (PC to Unix). In this class, our most common use of FTP will be moving your exercise data files between the Instructor's class account on Strauss to a PC and from a PC to your class account directory on Strauss.

    To FTP a GEOG 474 data file from Strauss to a PC (to download):

  • Open an MS-DOS window on a PC (Start...Programs)
  • Type cd c:\geog474 at the DOS prompt
  • Type ftp strauss
  • Log onto Strauss with your username and password
  • Type cd /home/base/usrb/geog474/intructor's_username or your_username at the FTP prompt
  • Type binary to transfer non-text data files (which most of your data files will be; to transfer text files, type ascii)
  • Type get filename to download the file to PC
  • Type quit when you are finished with FTP

  • Close the MS-DOS window
    To FTP a GEOG 474 data file from a PC to Strauss (to upload):
  • Open an MS-DOS window on a PC (Start...Programs)
  • Type cd c:\geog474 at the DOS prompt
  • Type ftp strauss
  • Log onto Strauss with your username and password
  • Type cd /home/base/usrb/geog474/your_username at the FTP prompt
  • Type binary to transfer non-text data files (which most of your data files will be; to transfer text files, type ascii)
  • Type put filename to upload the file to Strauss
  • Type quit when you are finished with FTP
  • Close the MS-DOS window
  • Using a Windows FTP Client on a PC
    On  the PCs in the Pearson Hall Training Center, double click on Applications on the desktop and then select FTP option.  The University web site below provides a  step-by-step guide to using windows FTP.
    Using a Windows FTP Client on a PC

    Part 2.  Introduction to Image Processing Software

        In the second part of this exercise, you will become acquainted with two image processing software systems called ArcView Image Analysis 1.0 and McIDAS 7.6.  The goal is to access each software system, become familiar with its Online help contents and view a satellite image(s).  Remember that ArcView's Image Analysis is only available on the PCs whereas McIDAS is found only on Geography's server.

    ArcView Image Analysis
    Start arcview from an IBM-compatible PC in Pearson Hall Training Center (Room 116)  or RDMS Data Center (Smith Hall 002C).  Also, the instructions below are specifically for accessing ArcView from Pearson Hall Training Center.
    From the Start menu, select Class Software--> ArcView GIS Version 3.1 --> ArcView GIS Version 3.1.
    A "Welcome to ArcView GIS" window will appear
    Select "Open as a blank project". Click OK.
    An application window appears with a smaller project window located within the application window
    From the Help menu, click on Help Topics.
    Help Topics: ArcView Help window appears.  This is the Online Help for ArcView.  It consists of Contents (book chapters), Index and a Find section.
    Review the following Contents of the Online Help.
  • Introduction to ArcView - specifically "What is ArcView?" and "ArcView's user interface"
  • Types of data you can use in ArcView
  • Extensions --> Image Analysis ** most important**
  • To assist you in zooming in on the most important features and aspects of ArcView's Image Analysis, answer briefly the following questions:

    1) What types of image data is ArcView Image Analysis able to directly read?  Which types can be imported?

    2) How can you get information about your image?  (Hint:  Metadata documentation)

    3) Examine Jensen's Figure 1-2 (Jensen, 1997, 9) - Fundamental Image Analysis Tasks.  Does ArcView appear to have the capabilities outlined in this Figure?

    Load the Image Analysis Extension and others useful in image interpretation and analysis by selecting the File menu and then select Extensions.  When the Available Extensions window appears, select the following extensions:
  • Image Analysis (currently not loaded, skip for now)
  • Imagine Image Support
  • JPEG (JFIF) Image Support
  • Spatial Analysis
  • TIFF 6.0 Image Support
  • Make these extensions default.

    Open a new View by clicking on the Project window and select New.  A blank View window will appear.

    Display the Landsat TM scene covering the Newark area.

    Click on the View menu and select Add Theme or click on the Add Theme button.

    An "Add Theme" window appears.  Select the Image Data Source under the Data Source Types.   Navigate Geog474 Folder and select the image called landsat_tm_denj_subset.img that your downloaded from the Instructor's strauss class directory.  Click the image On in the Table of Contents found in the View window.

    View the image as a False  Color Composite by double clicking on the image name - landsat_tm_denj_subset.img.  A "Legend Editor" window appears.  Select Band3 for the Red icon, Band2 for the Green, and  Band1 for the Blue. Also, select the linear button for Blue and  increase the contrast for the blue by moving the blue line to the left or more vertical. Then Apply the color composite.   The image should appear with lots of red tones that indicate healthy vegetation.

    What features are you able to discern on the image?  Can you pick out the Newark area, C&D Canal, forested areas, wetlands?
    Zoom in on the City of Newark and the University of Delaware using the following tools:
  • zoom in from a point or drag a rectangle
  • zoom out from a point or drag a rectangle
  • pan (hand) - drag display in direction move cursor
  • Can you identify the University of Delaware?  Can you pick out the Bob Carpenter Center, Perkins Student Center? Library? Lums Pond (where Department holds its Fall Picnic)?

    What applications do you feel this imagery is most appropriate for?

    To exit ArcView, under File menu, select Exit. You do not need to save the project.


    Online information describing McIDAS is found under the main Unidata Homepage.
    Unidata McIDAS (
    Actual documentation for Unidata McIdas is found under the Unidata McIDAS homepage listed above and within the Unidata McIDAS software.  Two valuable documents online are:
    McIDAS Learning Guide for Version 7.6
    McIDAS User's Guide for McIDAS-7.6
    Describe what is McIDAS's primary application?  What are its main features? Are  these features similar to features available in ArcView?  Are their distinct differences?
    Logon on the Geography SGI Server.

    Start McIDAS by entering "mcidas &" in lowercase from your home directory on the Geography SGI server.

    davinci% mcidas &

    A McIDAS session generates two windows - a text and command window and an image window.  You use the text and command window to enter McIDAS commands, to view the status of your McIDAS session and to display textual information from McIDAS commands.  The image window shows frames that display McIDAS images and graphics.  McIDAS applications are command-driven.  There are two basic command formats  - singe letter commands and multiple letter commands with positional parameters, keywords, and quoted text.

    The Online help provides abbreviated descriptions of the McIDAS commands listing the syntax of each command including the parameters, keywords, and remarks.    For a complete description of each command, see the Unidata McIDAS Users Guide . Examine the abbreviated Online help by issuing HELP in the text and command window.  A list of all the commands are displayed.  For help on a specific command type HELP followed by the command.
    HELP DF   - Online help to display digital areas
    Display 4-6 images for a particular day.
    Two commands - LA and DF - are used in listing and describing the images available and displaying the images in the image window.  LA displays a log of all areas available from the Unidata satellite feed.  Note the LA syntax which displays such information as the sensor, time of image, bands available, and spatial resolution.

    The satellite data is transmitted through the Unidata-Wisconsin data stream and ingested by one ot the Geography's workstation where is it stored in locations on disk called areas.  Unidata reserves area numbers 1-1999, and 9000-9999 for products in the data stream.  The default area numbers used for the products are found at:

    Unidata products default area numbers
    Examine GOES Visible, Infrared or other imagery available.  Use the example below for guidance.
    E.g., List the Digital Areas available for GOES-East North America VIS and display 6 areas numbered 140 through 145 centered on 40N and 80W with a reduction of 4.  Place a map over the image for reference.  Toggle through the digital areas 140 through 145 (toggle backward - ALT B)
    LA 140 145

    DF 140  1  EC 40  80 -4  6


    ALT A

    What information can you gather issuing the LA command?

    What is the difference between EC and IC option?

    Write a short paragraph outlining synoptic features observed for that day.  Any interesting features seen?  Indicate date and time of imagery you examined.

    To exit McIDAS, issue EXIT command.

    ENVI (Environment for Visualizing Images)

    Logon on the Geography SGI Server.

    Start ENVI by issuing the following:

    davinci% source /usr/local/rsi/envi/bin/envi_setup
    davinci% envi
    Examine the online Help found by clicking on the System lab in the main ENVI GUI
    - Look specifically at Preface and ENVI Overview

    - Also examine the image format supported under "ENVI Supported Input File Formats"
    Due on September 30, 1999.
    Return to Geog474 Homepage
    Last revised on September 22, 1999 by Tracy DeLiberty.