--- Start of Idrisi List message Many thanks to all who replied to the grayscale presentation query. The following are the replies received. Cheers, Sue *************************************************************************** I have not used IDRISI for several years - research redirection. However, I was involved in an issue similar to yours: Several items came to attention. 1) For us, Each printer produced a different output quality. A good output on a Laser III was not acceptable on a Laser IV. 2) After a lot of trial and error we were successful at producing grey scale. Black/White and at most 4 grey (generally 3 worked best). First the image was reclassed into the number of levels desired. Then each class was equated to a legend image. For most work, the image and legend were exported in tif and imported into WORD documents. (Also Posters: Powerpoint, Adobe, Corel etc.) Several tests prints were done with the legend to find grey scale that would print to that printer. What was discovered was there was not a pattern of scale value that would print a grey scale. Black and White were often used as 2 colors and then 3 grey values. One would expect say 4-4-4, 8-8-8, 12-12-12 to create equal grey scale increases, WRONG. It may be 4-4-4 6-6-6 and 14-14-14. For us it was trial and error, but that was 5+ years ago. Once a system was created it worked very well for that configuration, (printer, program, computer etc.). Update something and it all was required to be developed again. Our efforts at pattern were not acceptable; as long as groups of pixels were of the same pattern it was fine, as pixels varies in an area, the printed image did not give a proper visual impact. An Addition: Verify the publisher publication quality, often what was printed well failed to reproduce by the publisher, wash out and image burn. Good Luck in finding a good solution; Ours was trial and error (and successful). Donald E. Simmons ***************************************************************** I think with 5 classes, you should be able to represent it in greyscale. Make sure you don't evenly distribute the classes according to %black (or %saturation or whatever). The resulting tones will not be evenly "spaced" to our eyes. Our eyes are much more sensitive to subtle variations towards the white end of the scale. ie. instead of 0 25 50 75 100 try 0 10 30 55 100 or something along these lines. If that does not work with 5 classes, perhaps instead of putting patterns in each class, you could choose one class to add a pattern to - I suppose this depends on how complex the distribution of your classes is. Tom Albright ***************************************************************** I have successfully used greyscale with 5 classes for publications. 2 keys: 1.) work with another program (CorelDraw, PhotoShop, etc.) -- screen dump your Idrisi image to clipboard, then paste into your other application. 2.) use the "extremes" of the greyscale (that gets you 2 classes) and something about halfway on the scale (your third class) and a lighter and a darker shade (4th and 5th classes). You will need to experiment. I think 5 classes is the maximum. Gloria Rapalee ***************************************************************** I have done just what you are looking to do, but it required outside software. I used CorelDraw 8 which also comes with a program called Corel OCR-Trace 8. First, export the image as a TIF using the Idrisi16 palette (Idrisi32 lets you do this, I don't recall if I-2 does). Then, open the file in OCR-Trace and trace it using the "Accurate" settings, click "Apply" and let it roll. This will then take each color and create a vectorized shape of it. Save... Vector... use Corel Presentation Exchange (CMX), give the new file a name, and save. Now, open the new file in CorelDraw. You can now click on each color and change it's outline and fill properties. I suggest using a thin black outline on each and a postscript fill pattern. To create a black and white map with 5 or 6 classes, fill patterns are the way to go. Now that you have the image in CorelDraw, you can really manipulate it and make it look sharp! Hope this helped, Todd Albert ********************************************************************** There is free program ArcExplorer distributed by Esri (www.esri.com), were image look is easily controlled than in Idrisi. Program work with Shapefile. I hope it will help Matjaz Prosen ********************************************************************** Dr Sue Marrs Research Scientist University Marine Biological Station, Millport, Isle of Cumbrae. KA28 0EG. SCOTLAND --- End of Idrisi List message IDRISI-L is an unmoderated list. As a service to list users, please post a summary of useful responses to your questions. To post a message to IDRISI-L, send it to [EMAIL PROTECTED] To subscribe to the list, send an email from the address to be subscribed to [EMAIL PROTECTED] with "subscribe" (without quotes) as the first line of the message body. To unsubscribe, do the same, only with "unsubscribe" as the first line of the message body.
