IDRISI-L Frequently Asked Questions (FAQ) List (Version 1.4) 1. What is IDRISI? IDRISI is a raster geographic analysis software package develop- ed, distributed and supported by The IDRISI Project, a non-prof- it organization within the Graduate School of Geography at Clark University in Worcester, Massachusetts. To date, there are nearly 10,000 registered users of IDRISI in over 100 countries, making it the most widely used raster GIS in the world. IDRISI is designed to be affordable and easy to use, yet provide professional-level analytical capability on DOS PC plat- forms. IDRISI provides an extensive suite of tools for image process- ing, geographic and statistical analysis, spatial decision sup- port, time series analysis, data display, and import/export and conversion. In addition, as a set of independent program mod- ules linked to a broad set of simple data structures, the system is designed such that researchers may readily integrate into the system their own modules, written in any programming language. 2. What does IDRISI stand for? IDRISI is not an acronym! Idrisi was a cartographer and geo- grapher of major significance during the medieval period. He was born in 1099 AD in Sebtah (now the Spanish possession of Ceuta) on the North African coast of what is now Morocco. Commissioned by King Roger of Sicily to prepare a geographic survey of the world, Idrisi headed a collaborative effort by scholars and technicaians of the Rogerian Court at Palermo based on direct field studies as well as archival sources, the maps and text that resulted form that collaboration served as primary references for over 500 years. It is to this spirit of collaboration in geographic inquiry that the IDRISI Project is dedicated. 3. How Can I Get a Copy of IDRISI? The IDRISI software package is distributed solely by the IDRISI Project. To obtain information or to place an order, contact the Project at: The IDRISI Project Graduate School of Geography Clark University 950 Main Street Worcester, MA 01610-1477 USA (508) 793-7526 (508) 793-8842 (FAX) IDRISI@CLARKU.BITNET IDRISI@VAX.CLARKU.EDU Prepayment is required. Returns are not accepted. The IDRISI Project office hours are from 09:00 to 17:00 hours US Eastern Standard Time Monday through Friday. The telephone num- ber for technical support is (508) 793-7348 or (503) 793-7528. 4. What is IDRISI-L? IDRISI-L is an Internet and Bitnet discussion group for users of the IDRISI software package developed by the Graduate School of Geography at Clark University. The purposes of IDRISI-L are: 1) to foster communication among the community of IDRISI users; 2) to encourage the application of IDRISI to real world problems; and 3) to provide user feedback regarding IDRISI to the Graduate School of Geography at Clark University. IDRISI-L is supported by the Department of Geography and Environmental Planning at Towson State University. The "manager" of the discussion group, Dr. John M. Morgan, III ("Jay"), can be reached at: Department of Geography and Environmental Planning Towson State University Baltimore, Maryland 21204-7097 (410) 830-2964 (410) 830-3888 (FAX) E7G4MOR@TOE.TOWSON.EDU IDRISI-L is operated independently of the Graduate School of Geography at Clark University. That is, Towson State University has no formal or informal relationship with the IDRISI Project regarding the IDRISI software package. By supporting IDRISI-L, Towson State University is not endorsing the use of the IDRISI software package, per se, but rather is interested in fostering communication among academic, government, and commercial users of the software package. 5. How can I subscribe/unsubscribe to IDRISI-L? IDRISI-L is operating on Towson State University's VAX cluster. The discussion group is supported by MAILSERV as opposed to LISTSERV software. To subscribe to IDRISI-L send a one line message (SUBSCRIBE IDRISI-L) to either the Internet address: MAILSERV@TOE.TOWSON.EDU or the Bitnet address: MAILSERV@TOWSONVX To unsubscribe to IDRISI-L, send a one line message (UNSUBSCRIBE IDRISI-L) to either the Internet or Bitnet MAILSERV address. 6. Where is the IDRISI-L FTP site and how can I access this re- source? The IDRISI-L FTP site is operating on a MicroVAX that is part of of Towson State University's VAX cluster. The anonymous FTP site is located at: MIDGET.TOWSON.EDU or 131.118.70.11 After connecting to the FTP site, use ANONYMOUS as your account number and your Internet or Bitnet address as your password. All modules, data sets, and other IDRISI information is located in the IDRISI directory. It is recommend that you binary transfer all modules; data sets and the FAQ list may be trans- ferred as ASCII files. 7. What programs and data are located on the IDRISI-L FTP site? IDRISI users have donated several "modules" a. Modules 1) ASSIGNV - assigns values to vector identifiers from a values file. ASSIGNV parallels the functioning of the ASSIGN module, but works on vector rather than raster data in the TOSCA module. Vector identifiers are changed to the corresponding values, and a new file is written (the new file is identical to the original; only the identifiers are changed). The user is given the option to keep or discard vectors to which no values are assign- ed. Donated by Jeff Jones, Clark University. 2) AUTOLEG - creates a legend for IDRISI images for display with autoscaling (COLOR A). Donated by Rusty Dodson, NCGIA. 3) BUFFER - allows for buffers with direction to be applied to byte valued binary images. Handles pixels that are not square. The operator can specify the value identify- ing the cell to be buffered (called the "source value"), what cell is allowed to be written over (called the "tar- get value"), and what value to write in those cells that fall within the buffer distance and direction (called the "buffer value"). Donated by Simon Greener, University of Tasmania. 4) ENVIRON - an improved version of IDRISI's standard ENVIRON program. Uses "rolling menus" from which input can be selected for particular fields (e.g., available drives, screen colors, etc.). Compatible with Version 4.1 (detected from IDRISI.ENV being used). Donated by Simon Greener, University of Tasmania. 5) EPPL2IDR - converts EPPL7 images to IDRISI format. Dona- ted by Simon Greener, University of Tasmania. 6) EXPTOVEC - a very powerful module to import ARC/INFO ex- port into IDRISI vector format. It is possible to import topology using this module. Donated by Horst Duester, University of Bern. 7) GREENER - self-extracting (PKSFX) files of the Pascal source code for BUFFER, EPPL2IDR, and several other util- ities. Donated by Simon Greener, University of Tasmania. 8) IDR2BMP - converts an IDRISI image to bitmap for use with IMAGES under WINDOWS. Donated by Horst Duester, University of Bern. 9) ISLAND - cleans IDRISI vector polygon files imported with DLGIDRIS, IDR2DXF, IDR2ATL, and EXPTOVEC, or created with COLOR. Donated by Horst Duester, University of Bern. 10) MOSSID - converts MOSS data to IDRISI format. Donated by the IDRISI project. 11) MSPTOIDR.UCM - creates an ASCII file of MicroStation line element coordinates (lines = 2 vectors; points = 1 vec- tor. The ASCII file is created in IDRISI version 3.x vector file format. The "value" of the line or point is the "z" coordinate. Donated by Ed Riegelmann, Intergraph Corporation. Works in DOS and UNIX operating system en- vironments. 12) MSLTOIDR.UCM - creates an ASCII file of MicroStation line string element coordinates selected by fence. The ASCII file is created in IDRISI version 3.x vector file format. The "value" of the line is the "z" coordinate. Donated by Ed Riegelmann, Intergraph Corporation. Works in DOS and UNIX operating system environments. 13) MSSTOIDR.UCM - creates an ASCII file of MicroStation shape element coordinates. The ASCII file is created in IDRISI version 3.x vector file format. The "value" of the shape polygon is the "z" coordinate. Works in DOS and UNIX operating system environments. 14) MULTREG - performs simple or multiple regression proced- ures on IDRISI images. Outputs an ANOVA tape, a listing of Beta parameter estimates and related statistics, a list of predicted Y values, and (optionally) an IDRISI image which represents either the predicted Y or the res- idual value at each sample point (pixel). Donated by Fred Edberg, Murray State University. 15) RASCONT - given an IDRISI image of raster "polygons," this module makes a contiguity matrix in sparse form. Donated by Rusty Dodson, NCGIA. 16) RASDIST - given an IDRISI image of raster "polygons," this module makes a distance-based spatial weight matrix using inverse-power distance decay and maximum distance threshold parameters supplied by the user (the module al- so outputs an IDRISI-format vector file of polygon cen- troids). Donated by Rusty Dodson, NCGIA. 17) SP2FULL - converts sparse matrices to full format. Dona- ted by Rusty Dodson, NCGIA. 18) TGRDLG - provides for conversion of line and polygon data from TIGER Line files to DLG 3.0 format. The pro- gram includes its own documentation (TGRDLG /H). Donated by Minhe Ji, . 19) VIEW - allows a user to view, edit, and print IDRISI images under WINDOWS directly. Donated by Horst Duester, University of Bern. 20) WINDCUT - provides for the extraction of sub-images from originals as new images. The dimension of the sub-image may be read on a file or selected on the screen with a mouse and then written to a file. It is possible to per- form multiple cuts of the same rectangular area over a set of images. Donated by Marco Gabella, Politecnico di Torino. b. Data sets 1) Dr. John Snow's 1854 cholera epidemic data for London. There are 3 vector files in this data set: DEATH - cholera deaths STREET - London street map PUMP - water well locations Both .VEC and .DVC files are provided. Donated by Rusty Dodson, NCGIA. c. Other 1) The current IDRISI-L FAQ list. 8. What do I need to do to donate a module to the IDRISI-L FTP site? To donate a program or data module, contact Jay Morgan at the address indicated above. Arrangements will be made for trans- ferring the module to the FTP site. Program modules should al- so include a .DOC file that describes the operation of the mod- ule and E-mail contact if additional information is needed. Data modules should include a .DOC file that describes the scale of the original data (representative fraction), the date of the data, a description of the data source, the method of data cap- ture, projection information, and E-mail contact for additional information. 9. What graphics cards work with the new SVGA COLOR modules in Ver- sion 4.1? According to the IDRISI Project, cards that DO work with the SVGA COLOR modules include: ATI Vantage ATI Ultra Pro Diamond Speedstar 24 Diamond Speedstar 24X Diamond Speedstar Pro Diamond Viper VLB Genoa 8545 VL - 24 bit Paradise Swan Palette Plus 24 Trident 8900C Note that some users have reported problems with the Diamond Speedstar 24X and Trident 8900C cards, but other users have gotten them to work. To make the Diamond Viper VLB card work, install the Viper utilities into a directory on your hard drive. Type the following command at the prompt: VPRMODE VESA. This runs VPRMODE.EXE and loads the VESA driver. To uninstall, type: VPRMODE VESA -U. Chipsets that have worked with the SVGA COLOR modules include: ATI Cirrus ET4000 (Tseng 4000) Paradise Western Digital (Diamond Speedstar 24X & Pro) Video7 The following information regarding graphics cards may also be useful to you: a. Note that some strange results have been reported when run- ning WHICHVGA on Cirrus cards. b. If you are having strange problems with the display, but you are getting something, the problem may be your mouse driver. IDRISI modules support the Microsoft mouse driver. If you have a different mouse or mouse driver, try using a Microsoft one. In particular, if you have a Genius mouse driver, it will not work. Other ones may or may not work. c. Load the mouse driver before entering into the COLOR modules. If a mouse driver is not present in memory, you will not be able to exit the module by hitting Esc or Ctr-l Break. You will have to reboot. This is not the case for the VGA COLOR (COLOREVA) or COLOR85. It has to do with a 3rd party driver IDRISI uses for the SuperVGA modules. d. If your card or chipset is supposed to work, but does not, it may need to be configured for your monitor. e. Sometimes you have to run a program to put your card into VESA mode. For example, with ATI cards, you must run VVESA.COM. 10. Are there any useful tips or tricks for Version 4.1 that I have been identified by IDRISI users? a. The PLOT module in DISPLAY requires a minimum of 570K of RAM to work properly. IF you get a "GKS GRAPHICS ERROR" when trying to plot a vector file, free up more RAM, reboot your computer, and then try to run PLOT. b. If you have trouble trying to import a DEM using the DEMIDRIS module (particularly if you get an "UNABLE TO READ 0.0 AS A REAL NUMBER" error), try editing the DEM as follows before rerunning DEMIDRIS: Replace "0.0 " with "0.0000000000000000D+00" Note there are 18 spaces after the 0.0 in the "from string," and 15 zeros after the 0. in the "to string." c. If TIFIDRIS bombs when you are trying to import a TIFF file, try the following: 1) Rerun TIFIDRIS and note the information on the screen, particularly the number of rows, number of columns, and file header size. Note that even if TIFIDRIS bombs, it will most likely create the palette (.PAL file) for the TIFF file (check your data directory or subdirectory to be sure). 2) Run BIPIDRIS and use the information from TIFIDRIS to try to read the TIFF file. d. The following is a blue-to-gray-red palette that was donated by Rusty Dodson, NCGIA: 0 0 0 0 1 0 0 63 2 30 30 63 3 40 40 63 4 50 50 60 5 40 40 50 6 30 30 40 7 20 20 25 8 20 20 20 9 25 20 20 10 40 30 30 11 50 40 40 12 60 50 50 13 63 40 40 14 63 30 30 15 63 0 0 e. The following is a hysometric tint palette that was donated by John Harmon, Central Connecticut State University: 0 0 0 0 1 20 20 63 2 30 30 63 3 48 48 63 4 3 53 63 5 61 61 61 6 13 63 13 7 30 63 30 8 48 63 48 9 63 51 38 10 63 46 29 11 63 39 13 12 63 63 13 13 63 63 31 14 63 63 44 15 63 63 63 Codes 1 through 4 are blues for bathymetry in decreasing in- tensity for shallower depths; code 5 is for near coastal shallow depths (almost but not quite white); codes 6 through 8 are greens in increasing intensity as elevations increase; codes 9 through 11 are browns in increasing intensity for increasing elevations; and codes 12 through 15 is a color range from yellow to white for the highest elevations. f. The following is a suggested procedure for converting scanned polygon boundaries into IDRISI raster format: 1) The map which is to be scanned should contain nothing but polygon boundary lines. Use whiteout to remove unwanted features or trace the boundaries onto a separate sheet of paper. The map should be scanned as a bitmap image, not a gray tone image. 2) Scan the image at a high enough resolution so that the boundary lines are at least a couple of pixels wide (so that each polygon is separated from other polygons by border pixels. Convert the image to IDRISI format using the TIFIDRIS module. 3) Use CONTRACT to shrink the image (by pixel thinning) to the desired resolution. This should also remove most spurious pixels which may have been created by scanning "dirty spots" on the map. If a lot of small spurious pixels remain, you can use FILTER with the mode filter option to remove many (hopefully all) of these pixels. 4) Now the IDRISI image should be mostly correct, except there are border cells that will need to be removed be- tween polygons. Use ALLOCATE to allocate these cells to the nearest polygon. A few pre-processing steps are necessary before running ALLOCATE. a) Use RECLASS to reclassify border cell values to zero, and reclassify background cells to an arbitrarily high value (this is done so that border cells which are closer to the background that the polygon will be allocated to the background). b) If the reclassified is not in integer/binary format, CONVERT it to this format. c) Use DISTANCE on the reclassified image. This will as- sign each zero cell (border cell) a value equal to the distance to the nearest non-zero cell. This image is neded as an input to the ALLOCATE module. d) Use ALLOCATE to allocate border cells to polygons. For input, use the image from step c) as the "distance image," and use the image from step a) or b) as the "target image." 5) Use RECLASS to reclassify the background pixels to zero (or anyother desired value). The image should now con- tain raster polygons with no border pixels between them. If desired, you can run GROUP again to renumber the poly- gons continuously from 1 to n. Alternatively, use RECLASS to reclassify polygon values to the desired polygon-id values. This procedure was donated by Rusty Dodson, NCGIA. g. The following are several suggestions for converting IDRISI images to .BMP and .GIF formats: 1) Display the IDRISI image with COLOR or ORTHO, and "grab" it with a "screen grabber" such as HiJak or Pizazz Plus. Most screen grabber packages provide for manipulation of the image and export to formats such as .BMP and .GIF. 2) The TIFIDRIS module writes a .TIF file which can then be read by many graphics programs such as Paint Shop Pro, Graphics Workshop for Window, or Corel Draw. The graph- ics program can then be used to export to other formats. 3) The IMG2BMP module on the IDRISI-L FTP site writes .BMP files directly from IDRISI. h. The GEOREF subdirectory includes .REF files for converting NAD 27 to NAD 83 coordinates (and vice versa). The .REF files reference NAD 27 coordinates in feet and NAD 83 coord- inates in meters. To convert NAD 27 coordinates to equiva- lent NAD 83 coordinates in feet, you will need to create a new .REF file for the NAD 83 coordinates, change the "origin X" (false easting) from meters to feet, and change the "units" from meters to feet ("m" to "ft"). i. The following is a recommended procedure for importing DEM's from the USGS FTP site into IDRISI: 1) Download the file and its associated text file from the USGS FTP site. Use the UNIX uncompress utility to UNZIP the DEM. Download the DEM to your PC. 2) Change the IDRISI environment to the directory or sub-di- rectory containing the DEM. 3) Use the CR/LF module with option 3 to add carriage re- turns where there are only line feeds. Note: this usu- ally takes from 15 to 20 minutes). 4) Use the VAR2FIX module with option 2, and set the fixed length 1024. Note: this usually takes about 10 minutes. 5) Import the DEM into IDRISI using the DEMIDRIS module. Note: this usually takes 5 or more hours. 6) To view the DEM, set the viewing parameters by hand and use a scale factor of -5 to view the entire DEM. j. The following is a recommended procedure for importing IDRISI DEM's into the VistaPro program: 1) Convert the DEM image into integer-binary format. 2) Use the TRANSPOS module in IDRISI to invert the DEM (the bottom row should now be at the top, and the top row should now be at the bottom). 3) Rename the TRANSPOS'ed image to end as .BIN rather than as .IMG. 4) Start VistaPro and use the LOAD menu BINARY file format option to load the DEM. By default, VistaPro expects the cell size to be 30 meters by 30 meters. You may need to adjust the vertical exaggeration when you display the DEM to allow for a different cell size. 5) A land cover map can also be imported. It should be inverted and then reclassed so that the numbers repre- senting the various land cover classes correspond to those defined by VistaPro (see the VistaPro manual). 6) The reclassed land cover image must be converted to a .PCX format. One way of doing this is to use the TIFIDRIS module to convert the image to a .TIF format, and then use a paint program that can import a .TIF file and export a .PCX file. During this process, you must be careful to maintain the same numbers of rows and columns in the .PCX file as in the .TIF file. 7) Start VistaPro and use the IMPEXP menu PCX -> COL option to import the land cover image (.PCX file) and convert it to VistaPro's internal color table for use with the DEM. Note: this procedure was donated by Douglas Crawford, School of Landscape Architecture, The University of New South Wales, D.CRAWFORD@UNSW.EDU.AU. 11. What other programs are available for use with IDRISI? a. SpaceStat is a program that covers a range of descriptive spatial statistics, measurements of spatial autocorrelation, and tools to implement spatial analysis in regression mod- els. The program interfaces with IDRISI along with several other GIS packages. The package, which was developed by Luc Anselin, NCGIA, is available for academic and non-profit or- ganizations for $250 (including the GAUSS run time module) or for $250 without the GAUSS module. Additional copies of SpaceStat are available for lab use with no manual for $65; additional copies of the manual are $50. The cost of Space- Stat to for-profit organizations is $500. Rusty Dodson, NCGIA, has prepared a tutorial to supplement SpaceStat. The tutorial is NCGIA Technical Report 93-5, "Teaching Introduc- tory Geographical Data Analysis with GIS: A Laboratory Guide for an Integrated SpaceStat/IDRISI Environment." The report contains student laboratory exercises for an introductory course on spatial analysis. The report costs $13.50 and in- cludes a disk with datasets. Contact the NCGIA for addit- ional information regarding SpaceStat or Technical Report 93-5. b. FRAGSTATS is a spatial pattern analysis program for quantify- ing landscape structure. The raster version of the program will read IDRISI image files (the vector version is for use with ARC/INFO coverages). FRAGSTATS generates area metrics, diversity metrics, and contagion and interspersion metrics. A PC version of the program, along with documentation, is available via anonymous FTP at FSL.ORST.EDU. FRAGSTATS can be found in the PUB directory. Be sure to read the README.PS file and the documentation in the MAN directory; installation and operation instructions can be found in the FRAGSTATS.DOC file in the raster and vector directories. c. FMAGDIGT is a package that converts field mapping data (field survey notation) into mapping coordinates for IDRISI and SURFER (or into an HPGL plotfile). The program provides for the use of conventional field mapping methods (traverse and intersection) to solve either planimetric or three-dimension- al survey problems. FMAPDIGT is available from the AAG Microcomuter Specialty Group IBM Software Exchange for $1.00. Contact Bob Sechrist, Indiana University of Pennsylvania, at RPSECRST@IUP. d. The AAG Microcomputer Specialty Group has acquired the li- cense to the Atlas*Draw 2.0 and the Atlas Import/Export pro- grams. Atlas*Draw is a user-friendly digitizing package that handles enclosed polygons ("islands") very well, allows for the copying of line segments from one polygon to another (saving time in redigitizing common boundaries), handles con- trol points well, and supports a farily wide set of digitiz- ers. Atlas Import/Export provides for conversion of a number of different file formats (Atlas, DLG, TIGER, MapInfo, and ARC/INFO). The AAG Microcomputer Specialty Group is selling both packages for $50 (included are 3.5" disks, a photocopy of all documentation, and a site license). For information, contact Jim Snaden at SNADEN@CTSTATEU.EDU or (203) 827-7218. Orders may be sent to him in care of the Department of Geo- graphy, Central Connecticut State University, New Britain, Connecticut 06050-4010. Orders will be processed within 30 days of receipt. Checks should be made payable to the "AAG MSG." e. The NCGIA GIS Laboratory Exercises Volume 1 includes five exercises for IDRISI (along with three exercises for pcArc/Info. The exercises, which are designed to support the NCGIA Core Curriculum Volume 1, include an introduction to GIS, GIS data as representation of reality, suitability analysis, change detection, and forest management. For fur- ther information, contact the NCGIA about Technical Paper #91-12. The cost of the Laboratory Exercise volume is $25.00. f. Allan Branscomb (University of Oregon) has developed an AML for converting IDRISI files for use with the workstation ver- sion of ARC/INFO. The AML, which is called ARCTOID.AML, is available in compressed form via anonymous FTP from MARS.UOREGON.EDU. The AML is in the PUB directory, along with a README file that gives a description of the software and instructions for its use. g. Eric Lorup (Department of Geography and Botany, University of Salzburg) has developed a module called RECLASSR. This mod- ule is like the IDRISI RECLASS module with the important dif- ference that it generates real-binary output images from real-binary input images. As such, no data will be lost from truncation or rounding when reclassifying a real-binary image. The module is in the PUB directory of an anonymous FTP site at DGEO35.GEO.SBG.AC.AT. Use a binary transfer to get the file; PKZIP/PKUNZIP Version 2.04G is needed to ex- tract three files (Pascal source code, executable, and docu- mentation) from the PKZIP'ed file. For further information, contact Eric at ELORUP@GEO.SBG.AC.AT. h. Drake Environmental Consultants (East Bloomfield, New York) have developed a program that converts IDRISI .DVC and .VEC files to MapInfo .MIF and .MID files. This program, which runs under Windows, was written in MS Visual C++. For further information (including pricing and distribution pol- icies), contact Barbara Drake at LEEDRAKE@AOL.COM. i. Michael Bedward (Environmental Survey and Research Branch, NSW National Parks and Wildlife Services) has developed a program called CODA (Conservation Options and Decision Analy- sis). It is used to help design networks of nature reserves and other protected areas. The program is available via an anonymous FTP site at LIFE.ANU.EDU.AU in the PUB/BIODIVERSITY/SOFTWARE directory. Get the file called CODA05.ZIP. For further information, contract Michael at MBEDWARD%NSW.ERIN.GOV.AU@UUNET.UU.NET. 13. Where can I find data sets for use with IDRISI? GRID-Arendal, one of the nodes in the UNEP/GRID network of collaborating environmental GIS based data centers, has made available 19 data sets extracted from the global GRID database on their public domain server. The data sets cover the Baltic/Nordic region (4-40 degrees East, 48-72 degrees North), and include both raster and vector data. The raster data are in IDRISI format, and the vector data are in IDRISI-importable ARC/INFO ungenerate format. Some of the data include: Holdridge life zones under present and doubled CO2 levels; Olson major ecosystem complexes; monthly maximum global vegetation indexes (derived from NOAA AVHRR data) for the years 1983, 1986, and 1989; and World Databank II boundaries, coastlines, major rivers, and railroads. Metadata is also available on-line. The login procedure to the public domain server is "guest" based, not "anonymous". The data are also available on 4 floppy disks (3 1/2") plus documentation. GRID-Arendal charges a handling fee of $20 US for the diskettes and documentation. For further information, contract Sindre Langaas, GRID-Arendal, Department of Systems Ecology, Stockholm University, at GRID@GRIDA.NO. June, 1994 .