1.1 What is GRASS? 1 1.2 Usage for the VPE Laboratory 1 1.3 Tutorial 4 1.3.1 Logging on to the computer 4 1.3.2 Starting up GRASS 4 1.3.3 Creating a GRASS Database for use with the Mars data 5 1.3.4 Accessing Mars Data from the CD-ROM 7 1.3.5 Creating the GRASS header Support Files 9 1.3.6 Registration using Kilauea Data 11 1.3.6.1 Specifiying the Location and Mapset 12 1.3.6.2 Customizing the Database Environment and Selecting the Graphic Output Device 14 1.3.6.3 Obtaining a Grey Scale 14 1.3.6.4 Grouping the first Raster Image 16 1.3.6.5 Targeting the First Image 17 1.3.6.6 Using `i.points' on the First Image 18 1.3.6.7 Rectifying The First Image 19 1.3.6.8 Grouping the Three Other Images 20 1.3.6.9 Targeting The Three Images 21 1.3.6.10 Using Points on the Three Images group to prepare to Register with the First 21 1.3.6.11 Rectifying the First Image Group to the Three Image Group 24 1.3.7 Visualization of the Kilueau Mapset 25 1.4 Resources 33 1.4.1 Software 33 1.4.2 Databases 33 1.4.3 Tutorials 34 1.4.4 Newsgroups 34 1.4.5 Programming notes 35 1.4.6 GIS Mailing Lists 35 1.4.7 GRASS Mailing list 35 1.4.8 Useful Information obtained from the Mailing List Archive: 39 1.4.8.1 Compiling Grass on IRIX 5: 39 1.4.8.2 Mars Data 41 1.4.8.3 Searching through the grassu-list archives 41 1.4.8.4 Histograms 42 1.4.8.5 Color display in GRASS explained 42 1.4.8.6 Running GRASS programs without starting grass 43 1.4.8.7 Sample usage of r.mapcalc 43 1.4.8.8 Autocad DXF files 44 1.4.8.9 Databases and GRASS 44 1.4.8.10 New r.in.hdf Command 45 1.5 Appendix 46 1.5.1 Stanford Workshop GRASS Tutorial --- 1.5.2 C Code Written During Installation --- 1.5.3 Installation Size --- 1.5.4 VOLINFO.TXT Mars CDROM ---
This section does not currently apply.
This document uses 12 point Times New Roman Font.GRASS stands for Geographic Resources Analysis Support System, and is a widely used software package allowing one to manipulate geographical information. Software like GRASS is known as a Geographical Information System (GIS). GRASS is released free of charge by the US. Army Corp. of Engineers (The FTP site for obtaining it is in Section 1.4: Resources)
The internet posts a monthly NetNews article in net.answers called the 'GIS FAQ' that answers Frequently Asked Questions about GIS systems. Two definitions cited are:
A GIS is ...An information system that is designed to work with data referenced by spatial or geographic coordinates. In other words, a GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for working [analysis] with the data. (Star and Estes, 1990)
... simultaneously the telescope, the microscope, the computer, and the Xerox machine of regional analysis and synthesis of spatial data (Abler, 1988).
A typical use for GRASS would be the creation of a map suitable for urban development. The map might be required to show vegetation, all areas that are currently range land, plus any slopes equal to or less then 15 degrees. For this application, the GRASS database would contain several types of data; such as Digital Elevation Models (DEMs) with x,y,z information, raster pictures (perhaps from LandSat photos), road locations, and vegetation densities.
With GRASS you can display these types of data easily and in relation to each other (only several display commands are needed). You can overlay the raster pictures on the DEM data, and include road and vegetation information. You can then zoom in on areas of interest, and using the database functions of GRASS, do queries for additional information.
The VPE GRASS installation contains a sample database (spearfish, located in Montana), that can be used to create a map of this type. A tutorial (Section 1.5.1 Stanford Workshop Grass Tutorial) is included that shows the procedures for this process.