Introduction to GIS/Remote Sensing in Forest Science Research Network

The primary GIS software package is ARCGIS with its many modules. ARCGIS is licensed by the Environmental Systems Research Institute in Redlands, California. We are currently running version 8.2 of ARCGIS on the PC side and version 8.01 of ARC/INFO on the UNIX side, and version 3.2 of ArcView (available on both UNIX and PC).

ARC/INFO on the UNIX machines

To start ARC/INFO on the UNIX machines, type "arc80" at a command prompt in a terminal window. That terminal then becomes your ARC/INFO interface. To run ArcView, type "av32" in a terminal window, and the ArcView screen will appear on the same workspace. If you type "av32 &", the ArcView session will run in the background and you will still be able to use that terminal for other processes.

ArcGIS on PC Machines

You have the option to run Arc/INFO workstation on the PC or run modules of ArcGIS. ARC/INFO workstation works just like the UNIX version of ARC/INFO except that you have the DOS operating system. You access this program, from Start, you click on programs>arcgis>workstation arc info. A small black rectangle will appear on your screen with an arc prompt. You then execute arc commands.

ArcGIS is a new product by ESRI that provides several user friendly modules to facilitate ease of use. Several modules are available, depending on how the install was performed on the machine: ArcCatalog, ArcMap, ArcToolbox, ArcScene, ArcReader, and ArcObjects Developer Help. The three primary modules that are used are ArcCatalog, ArcMap, and ArcToolbox.

ArcCatalog works similar to windows explorer, although you can look at GIS data, review the geography and tables, create new data layers, add items to tables, copy and paste data from one directory to another, and create, edit, view, and query metadata files.

ArcMap is where you create maps, edit data, and perform analysis within the geodatabase structure. This program works similar to ArcView, although there are some nice additional functionality. As a side note, it is important that you DO NOT EDIT COVERAGES IN ARCMAP. There are several problems with this functionality. Editing of coverages should be done in the ArcEdit module of ARC/INFO.

ArcToolbox is where you perform many of the ARC/INFO functions through wizards and interfaces. You can use programs in here to project data, copy, change format, import and export, and do analysis.

• ARC/Info Geographic Information Systems
  
• ARC/Info Tips and Tricks
  
• The 10 Commandments of ARC/Info
  
• Programming in ARC/Info Macro Language (AML)
  
• ARC/Info Frequently Asked Questions
  

• Using ArcView 3.0
  
• ArcView Extensions
  
• Metadata Collection in ArcView
  
• ArcView Frequently Asked Questions
  

• ArcInfo 8- A new GIS experience!
  

• Printing from ARC/INFO and ArcView

In addition, you may wish to download these QSG workshop documents (in Microsoft Word 97 format) which detail exercises in Avenue script generation and the Spatial Analyst extension in ArcView:

• Download Introduction to Programming with AVENUE
  
• Download Avenue Scripts and Extensions
  
• Download Spatial Data Analyst

Remote Sensing

• Introduction to Remote Sensing with Imagine 8.4
  
• Advanced Remote Sensing with Imagine 8.4
• Imagine Frequently Asked Questions
• ERDAS Support Site

Finding Geospatial Data

Format- Spatial data can be in many different formats. Most often, point and vector data are in ARC/Info formats, such as ARC export files (*.e00) or ArcView shapefiles (.shp, .shx, .dbf), and raster data are in Generic Binary, Ascii (*.asc), ARC Grid, GeoTIFF (*.tif), or Imagine (*.img) files. Make sure you know what data format you are getting when you receive spatial data. Commonly, you will 'import' the data into the software that you have available. In order to do this, you may need to know some particulars about what platform and software produced the file.

Data structure- The spatial data file structure can be written in a variety of ways depending on the range of the data and the need to conserve file space. Generic binary files should have an accompanying .header file which describes the data structure of a file. Use this during the import procedure. Most image files are Unsigned 8-bit, which allows 256 (28) data values for each band, but you will also come across Unsigned 16-bit, Signed 16-bit, and Floating Point data files. Within ARC/Info, coverages can have Single or Double precision- Double has more significant digits but requires more storage space. You can examine the precision of a coverage with the DESCRIBE command. In addition, you may want to compress your spatial data set. Imagine and XV can do this for you, or you can use the compress or gzip commands in UNIX, or WinZip in NT to reduce file size.

Map projection- Every spatial data set should be referenced to some geographic plane. DO NOT assume that you know what projection, spheroid, and datum a file is in- Always check! The default projection for ArcView is Geographic, where X values represent longitude and Y values are latitude, in a decimal degree form. You can usually tell if your data values are geographic by examining the values in a viewer. Other common projections are Lambert (for all of Oregon), Universal Transverse Mercator (UTM zone 10, for western Oregon), and State Plane (used by many counties). Each has one or more standard spheroids and datums. For more information on this topic, see the study sheets for The Geographer's Craft at the University of Colorado.

Scale- Vector data usually has an associated scale or Minimum Mapping Unit (MMU), which is derived from the scale of the source maps or information used to create the vector coverage. For example, if someone constructed a coverage of roads by digitizing them off of a USGS 1:100000 topographic map, that coverage would have a scale of 1:100000. Therefore, there could be other coverages of the same information, but at different scales. Try to select which scale you need based on the size of your study area and other considerations. The MMU is minimum limit for features that are contained in a coverage.
For raster data, the scale is the size of one pixel, which is given in X and Y coordinates.

Version- Spatial data are frequently updated, edited, or otherwise changed from former versions. It is a good habit to attach a date or version number to your copies so that you will know which version you are using.

Metadata- Metadata encompass the information about a spatial data set. The metadata document should comply to the Federal Geographic Data Committee (FGDC) standards, and should be available with the spatial data set. As you import and analyze a data set, always keep the metadata handy for reference. And if you have created and intend to distribute spatial data, you must create metadata as well. For more help, see the FGDC Metadata page. For a review of the Metadata generation tools we have in FSRN, see George Lienkaemper's summary.

Image Processing

xv, which is solely for personal use, allows you to view a variety of images and convert between different image formats. You can launch xv by typing "xv" at the UNIX prompt in a terminal. Click the right mouse button in the startup screen to get the control menu. There isn't any help, but if you play around with it enough, you'll be able to figure out quite a bit.

Image Alchemy is a powerful image conversion program crafted by Handmade Software, Inc, out of Fremont, California. Alchemy is a command line program, which means that it works like a UNIX command with lots of options. There is a manual available here, which can be read by Adobe Acrobat, but you might want to start by viewing some of these conversion examples.

Mapping Software

Poster Display

Statistics

Help!!!

You should also become familiar with the Forestry Network web page for GIS and remote sensing help.

Next you will want to peruse the GIS/RS Help Notebook, kept on the shelf between Picea and Populus in FSL Rm 345 (GIS Lab). Inside this notebook, you will find several years worth of training sheets, tips, and personal experiences.

On the same shelf you will also find user manuals for UNIX, ARC/INFO, ArcView, Imagine, Alchemy, and SPLUS. If you intend to become self-reliant, you should become familiar with these aids. The UNIX for Dummies guide is especially useful for learning UNIX commands. The ARC/INFO manuals tend to duplicate the on-line help, however the Imagine Tour Guides and ERDAS Field Guide are than what is available within the software, and both sources should be familiarized.

During certain times, you can consult the GIS/RS Help Desk Schedule to ask questions of experienced staff and students in the building. These volunteers have a variety of skills and if they cannot help you directly, they may be able to point you in the right direction. In addition, the CFSL Spatial Data Managment Group meets once a month and may be a good place to learn more.

There are several electronic mailing lists to which you may post your questions as an email message. The recipients of your message depend upon which list you select:

• helpdesk@fsl.orst.edu- For NT, Windows, or Macintosh-related questions in FSL.
  
• unix@fsl.orst.edu- For UNIX-related questions or announcements in FSL.
  
• support@fsl.orst.edu- To report problems concerning hardware or to request help with a specific UNIX procedure.
  

• forgis@cof.orst.edu- For ARC/INFO, ArcView, and general GIS or Remote Sensing questions within FSL. Subscription information.
  
• arcinfo@mail.orst.edu- For ARC/INFO announcements or questions campus-wide. Subscription information.
  
• APPLIED-GIS-RS@LISTES.ULAVAL.CA- Applied GIS & Remote Sensing mailing list hosted by the University of Laval, Quebec, Canada. Subscription information.
  
• consgis@pete.uri.edu- A worldwide distribution list for discussion of technical GIS issues related to natural resource conservation. Subscription information.
  

• erdas-l@erdas.com- A worldwide ERDAS Imagine discussion list to help with problems. Subscription information.
  

If you feel you must direct a question to ESRI regarding one of their products, you must go through one of our campus representatives who will forward your question to the ESRI technical staff. Please send an email to Matt Gregory with the following information:

Software:
Software Version:
Operating System:
Operating System Version:
Command Name if applicable
Detailed description of the problem, including the command used and the exact wording of any messages.

Finally, as your knowledge increases and your interest grows, you may wish to invest in one of several GIS or RS training workshops or classes. Many software industries, government agencies, and educational institutions offer training courses. For example, see these web links:

Comments & suggestions