Software Review
Journal of Geographic Information and Decision Analysis, vol. 1, no. 2, pp. 151-157, 1997

IDRISI for Windows 2.0

Slobodan P. Simonovic
Natural Resources Institute and the Department of Civil Engineering, The University of Manitoba, Winnipeg, Canada, R3T 2N2


1. General Information

Name and Version of the Software IDRISI for Windows Version 2, March 1997
Software Vendor/Programmer Clark Labs for Cartographic Technology and Geographic Analysis
Clark University, 950 Main St., Worcester, MA 01610-1477 USA
Platform Availability PC
Operating System Requirements Windows 3.X, Windows 95, Windows NT 3.5x or 4.0
Compatibility with OS/2 Warp, SoftPC, and WABI (not guaranteed)
Hardware Requirements
Processor 80386 and up; high-end 80486, or better, recommended
RAM 4 Mb (8 Mb, or greater, recommended)
Disk Storage 15 Mb for program
33 Mb for tutorial exercise data sets
Video 8 bits minimum (15 bits optimal)
Ideal resolution 1024 X 768
Available Media CD-ROM and 3.5 inch diskette
Language Availability English, French, Spanish, German, Russian, Chinese, and Portuguese
Technical Support Availability Telephone, fax, e-mail, and Internet
Cost Commercial US $990

Research/Non-Profit/Government US $695

Academic US $495

Full-time student US $247.50

Elementary/secondary school US $100

Student starter US $95

Site license US $2,475 (minimum 10 seat license)

General Software Capabilities
Geographic Analysis Database query
Map algebra
Distance operators
Context operators
Image Processing Restoration/Enhancement
Signature development
Hard classifiers
Soft classifiers/Mixture analysis
Accuracy assessment
Core Functions Environment/Project management
Data entry
Data reformatting
Raster/Vector conversion
Decision Support AHP for weights selection in a multi-criteria evaluation
Single and multi-objective ordering of cells
Multi-objective land allocation
Multi-dimensional conflict resolution
Probability and Bayesian decision making
Dempster-Shafer weight of evidence
Fuzzy set membership evaluation
Monte Carlo simulation
Change and Time Series Analysis Change analysis through differencing and ratioing
Standardized principle components analysis
Data Import/Export General conversion tools
Government agency data formats
Desktop publishing formats
Software-specific formats
Useful Web Sites IDRISI Project Home Page:
IDRISI for Windows WWW Tutorial:

2. Ratings

The following table presents ratings for the software in eight categories: GIS, mapping, decision analysis, modeling, image processing, multimedia, user-friendliness, and ability to customize the software.
The rating system is as follows:
1=POOR: Nonexistent, incomplete, inadequate, buggy, etc.
2=FAIR: Difficult to use, quirky, not organized, not intuitive, etc.
3=GOOD: Sufficient capabilities, organized, satisfactory presentation, no bugs, relatively easy to learn, etc.
4=VERY GOOD: Solid fundamental capabilities and more, easy to learn and use, nicely organized, good presentation, etc.
5=EXCELLENT: Extensive and impressive capabilities, nice surprises, very easy to learn and use features, outstanding organization and presentation, etc.
GIS Capabilities
Formal Decision Analysis Capabilities
Modeling Capabilities
Image Processing Capabilities
Multimedia Capabilities

3. Review

IDRISI software is named after the Spanish geographer Idrisi (born in 1099) who devoted most of his life to the goal of preparing a geographic survey of the world. Following his ideas, this software package is probably one of the major steps in contemporary times towards assisting professionals, academics, and others involved with spatial data analyses all over the world. Created and distributed since 1987 under the spirit of democratization of technology, IDRISI is used today in more than 130 countries, available in five languages, and supported by ten resource centers (in Austria, United Kingdom, Hungary, Brazil, China, Costa Rica, Poland, Russia, Spain, and Switzerland).
        IDRISI is a professional geographic information and image processing system. It is one of the largest raster-based microcomputer systems on the market which integrates the use of both vector and raster data layers. The system provides very good facilities for geographic analysis and environmental modeling. A friendly user interface, and good map composition and display systems allow access to over 150 analytical modules. IDRISI has pioneered the development of special tools for GIS-based multi-objective decision making, uncertainty management, and risk assessment.

3.1 Interface, Display, Input and Output

The IDRISI system consists of a main interface program equipped with a menu and toolbar system and over 150 program modules that provide facilities for the input/output (I/O), display, and analysis of spatial data. The interface is very friendly and similar to many Windows-driven applications. The main screen is divided into several regions. The menu system is accessible at the top of the application window and can be activated with the mouse or keyboard. Just below the menu is the tool bar, a set of buttons that represent either a program module or an interactive operation. At the bottom of the screen is the status bar that provides information about program operation. IDRISI contains an extensive on-line context sensitive help that can be accessed in a variety of ways. Most of IDRISI functions have their own window. By double-clicking with the mouse on any input entry box, available files with input data can be displayed in list form and then selected with the use of mouse operations. This version of IDRISI has a powerful, extended cursor inquiry which can be activated through a display preferences dialog box. Extended cursor inquiry is activated by specifying a group of images associated in a new display preference dialog. Whenever cursor inquiry is used with any member of a group, a special window opens listing a table of values for all members of the group. Values can be displayed in the form of a graph, too.
        Windows can be easily customized using numerous options related to the title, layer frames, scales, legends, text frames, logo, etc. Palette modification and legend caption editing are interactive. Automatic display of analytical functions is available. Automatic display causes the results of analytical operations to be displayed after the operation has been completed. The system estimates whether the data should be considered as qualitative or quantitative and use the appropriate palette and legend options.
        IDRISI supports data input from three main sources: (a) digitizers, scanners, and global positioning systems; (b) import of pre-existing data in IDRISI format; and (c) import and conversion of data in commonly available non-IDRISI file formats (Arc/Info files or satellite imagery). TOSCA, a DOS-based digitizing package, is no longer supplied with the IDRISI system. However, a new Windows-based digitizing and editing package is under development. IDRISI can import data in a large number of formats. Also, IDRISI can work with seven data forms: ASCII integer; ASCII real; byte binary; binary integer; binary real; packed byte binary; and packed binary integer.
        Probably one of the biggest additions to Version 2 is the printer workshop facility that provides a very good interface between IDRISI and printers supported by a Windows driver. The importance of this addition is demonstrated by making a copy available free of charge to all IDRISI users (even users of Version 1) via the IDRISI web site.
        Equally important is the first attempt of multimedia enhancement through media viewer. This feature offers animated displays of time-series images and video clips, and audio enhancements with the playing of sound files (.wav). This is a 32-bit application and requires Windows 95 or Windows NT operating system.

3.2 Image Processing

The main thrust of the IDRISI system is decision support. Therefore, Version 2 has expanded into the area of classification of remotely sensed images. Within this version, a set of traditional classifiers has been extended by the soft classifiers based on fuzzy sets. New image processing capabilities are definitely beyond the expertise of this reviewer, however it is obvious that IDRISI Version 2.0 continues to improve the image processing capabilities by adding tools capable of such tasks as radar data analysis and accurate classification of images in dynamic landscapes.

3.3 Geographic Analysis

The IDRISI system allows powerful and easy geographic analysis. Five categories of tools are available to users for performing database queries, map algebra, distance operations, context operations, and statistical analysis. Analyses can be automated with the use of IDRISI macros. I was quite impressed with the database workshop. With this tool, the tasks of creating, opening, editing, and modifying databases was very easy (especially if the user possesses some experience with other database management software). This tool makes the use of SQL queries rather easy, and provides the ability to perform powerful database queries. One of the most impressive features of database workshop is the ability to link the database to a map composition. This provides the user with the power to perform interactive, geographic inquiry and exploration.
        Also, Version 2 provides an image calculator, a mathematical modeling tool that lets the user enter a model as a full, algebraic equation. Most map algebra and database query operations can be executed from this calculator-like interface.

3.4 Decision Support

The IDRISI Project's commitment from 1987 has been to provide a very strong spatial decision support system. Version 2 continues the tradition by adding uncertainty management and decision strategy analysis to the already substantial set of tools for multi-criteria decision analyses. Very nice changes have been made to the fuzzy tool for evaluation of the fuzzy membership values. A user can now define membership function options and select the output format. New procedures together with older capabilities provide the means for straightforward suitability analysis, which has application in a number of areas, such as ecology (for example, habitat suitability), geology, environmental management, etc.
        Multi-criteria modeling in Version 2 of IDRISI is achieved by one of three procedures. The first involves Boolean overlay where all criteria are reduced to logical statements of suitability and then combined by means of one or more logical operators such as intersection and union. The second is known as weighted linear combination where continuous criteria are standardized to a common numeric range, and then combined by weighted average. The third option is known as ordered weighted average which has the ability to offer a complete spectrum of decision strategies along primary dimensions of the degree of tradeoff, and the degree of risk aversion in the solution.
        Uncertainty management is supported by a group of new procedures for weight of evidence modeling, including evaluation of multiple hypotheses with BAYES and a Dempster-Shafer analysis of evidence with BELIEF. The role of this latter module is in the development and revision of a knowledge base concerning a set of hypotheses.
        A revision of multi-dimensional choice procedure now allows up to four levels of abstraction on either the most or least suitable choice from a set of alternatives. For each pixel the best choice, the next best choice, the next next best choice, and so on, can be estimated. For example, in multi-criteria modeling of vulnerability to drought, the magnitude of this vulnerability from location to location can be estimated. These same criteria can then be used to determine primary, secondary and tertiary causes of vulnerability for each pixel.

3.5 Change and Time Series Analysis

IDRISI for Windows Version 2 has improved the time-series analysis capability considerably by adding a 32-bit version of the TSA tool for long time series (up to 256 input images) principal components analysis. In the new version, development of transition models is facilitated by the addition of multireg and logireg tools for multiple regression analysis and logistic regression analysis, respectively. These models can help in a variety of applications, such as land use analysis with the goal of identifying the probability of change based on a multivariate model.

3.6 Documentation and Support

The IDRISI system is distributed with the following: (a) a user's guide; (b) a quick reference; (c) an installation guide; (d) twelve 3.5" disks or one CD-ROM; (d) a book of tutorial exercises; and (e) selected inserts, news, etc. The installation process was very smooth (I was replacing IDRISI for Windows Version 1 with Version 2) and efficient. In this regard, the installation guide is quite clear and easy to follow. The quick reference booklet could be useful, but I did not yet feel the need to use it - possibly because of my previous experience with the IDRISI system. The user's guide is a comprehensive document with the majority of sections written for advanced users. My recommendation to beginners is that they not look at the advanced topics before obtaining a strong familiarity with GIS and the available GIS tools. On the other hand, the tutorial guide is recommended for everyone. The guide itself, and the set of tutorial data sets provided with the software are of great help in mastering this powerful system. The tutorial contains 17 introductory exercises and 15 advanced exercises. These exercises gradually increase in complexity, and their structured development of material from exercise to exercise provides an essential step in understanding spatial analysis, learning to use GIS, and mastering the available software tools. Additional learning tools are available through the efforts of the Austrian Resources Center, which created a web-based tutorial (web site address provided above).
        I did not use the available technical support. However, the options are impressive (phone, fax, e-mail, web site, resource centers), and the technical support is free for the first 60 days.

4. Overall Impressions

IDRISI for Windows Version 2 builds on the strengths of previous IDRISI developments in the area of spatial decision support. The addition of two new directions, uncertainty analysis and decision strategy analysis, make an important technological contribution. The developers are forging ahead on important paths for the future of GIS applications. Furthermore, tools previously incorporated into IDRISI for Windows correspond with ongoing developments in the field of GIS (dynamic modeling, multimedia, etc.). Thus, IDRISI as a product for PC environments has a very strong position in the marketplace.
        IDRISI for Windows Version 2 is a professional-level geographic information and image processing system for variety of users. It can be used with equal success in the private sector, government agencies, research institutions, academia, and elementary or secondary schools.
        Judging based on this product, my opinion is the IDRISI development team is successful in moving forward with the goal of democratization of technology

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