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<TITLE>Re: [GRASSLIST:3] Re: New GIS Manager adds transparency to layers</TITLE>
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<FONT FACE="Verdana, Helvetica, Arial"><SPAN DEFANGED_STYLE='font-size:12.0px'>IR17;m co-teaching an interdisciplinary Remote Sensing and Quaternary Landscapes class with a couple of colleagues in other schools. We decided to show students how to do some basic GIS-related tasks like import a DEM, reproject it from latlon to UTM, do a shaded relief map, drape it with color, create basic slope and aspect maps, and do profile analysis—and do it on 2 systems ArcGIS 9 and GRASS 6.1.<BR>
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My colleague (who is eager to learn more about GRASS) did this in ArcGIS this week and I will do the same in GRASS after Spring Break. Having barely touched Arc in a couple years now, I was feeling bad about showing students the complications in getting GRASS started and some of the esoteric aspects of this complex program. Then I watched the ArcGIS presentation. Easy to start and then the difficulties started. Sure you can open any map in an projection, but... Getting the projection right so that the maps actually overlay correctly is more difficult than in GRASS. Hill shading/shaded relief is about the same in both. Draping is definitely more versatile in GRASS—especially with the new transparency. Slope and aspect are marginally easier to do in GRASS and much easier to find in the menus. Profiling is a LOT easier in GRASS, even though it is still tied to the x11 displays. Several times my colleague mentioned, if only we could... And I said, you can do that in GRASS. For example, after finally getting profiling to work in ArcGIS (He needed to restart...so I don’t feel quite so embarrassed about occasional lockups in the GIS Manager, though a want it to be bug free), he said, if only we could output the profile points in some way. GRASS has a couple ways to do this—via d.profile and r.profile. <BR>
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Since I’ll be following the ArcGIS demo, I’ll be able to feel pretty good about the GRASS demo when I do it.<BR>
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Michael<BR>
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On 3/10/06 5:01 PM, "Ian MacMillan" <Ian.MacMillan@pomona.edu> wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>Michael, I haven't tried this out yet, but it sounds excellent. Cheers to all of your efforts to make GRASS more user-friendly for newbies. I am going to feel less guilty about making my students use GRASS in their classes instead of Arc. <BR>
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-Ian <BR>
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On Mar 10, 2006, at 12:59 PM, Michael Barton wrote: <BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12.0px'>I’ve just finished phase 2 of the GIS Manager update and it’s pretty exciting. At first glance, it looks a lot like the one I’ve been working on and have in the CVS now, but with a couple of important exceptions. One is that transparency is now supported for all GRASS layers. <BR>
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The second will probably generate the most discussion, so I’m ready to duck and run for cover. Now GRASS is consistent with other GIS programs and more intuitive (as much as I am skeptical about that term) in that the uppermost layer in the layer tree is also the top map in the display. Related to this, new layers insert directly above the currently selected layer instead of at the bottom of the layer tree. <BR>
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The main changes come ‘under the hood’ of this version of the GIS Manager. It uses g.pnmcomp to composite a set of maps (each rendered as *.PPM files) into a visual display. One of the results is that now GRASS is significantly faster in adding new layers, turning layers on and off, and changing layer attributes—only the new or changed layer needs to be rendered; the others will just be re-composited into a display from existing PPM files. This all happens in a GRASS .tmp directory, so that it doesn’t clutter up your home directories. The other important thing about this new architecture is that it makes GRASS even less dependent on the xdriver and PNGdriver for visualization. GRASS can become more easily portable to different OS’s and GUI frameworks. It is also more scriptable. You can write a script that will create a complete, multilayered map, and output it to a graphics file. <BR>
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One consequencer of this new architecture is that the GIS Manager does not currently support display output to PNG files. With GDAL (required for many GRASS features) and ghostscript installed, it does support output to PPM/PNM, TIF, JPG, BMP, EPS, and PDF. <BR>
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Command line usage is still supported in several ways—the old xterminal is still there, there is the new command console, and you can add command layers to the layer tree and display them. <BR>
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You can see a screen shot of semi-transparent soil vector areas overlaying a raster shaded relief map at <BR>
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<FONT COLOR="#0000EE"><a href="http://www.public.asu.edu/~cmbarton/files/grass_screenshots/gism2-2.jpg">http://www.public.asu.edu/~cmbarton/files/grass_screenshots/gism2-2.jpg</a></FONT> <BR>
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I’ve committed all changes to the CVS. For those of you with binary versions of GRASS who would like to try it, I’ve posted packages you can use to replace your current GIS Manager on my website. For full functionality, you need a version of grass that is dated 21-February-2006 or later. For those of you with a slightly earlier version, I made a second package with all functionality minus transparency. Here are the links. <BR>
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New GIS Manager files <BR>
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<<FONT COLOR="#0000EE"><a href="http://www.public.asu.edu/~cmbarton/files/grass_gismgr/">http://www.public.asu.edu/~cmbarton/files/grass_gismgr/</a></FONT></SPAN></FONT><SPAN DEFANGED_STYLE='font-size:12.0px'><FONT FACE="Lucida Grande, Verdana, Helvetica, Arial">gism_rc4_20060307.tgz></FONT><FONT FACE="Verdana, Helvetica, Arial"> <BR>
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</FONT><FONT FACE="Lucida Grande, Verdana, Helvetica, Arial"> New GIS Manager files for people with recent, but pre-21 February 2006 binaries.</FONT><FONT FACE="Verdana, Helvetica, Arial"> <BR>
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<<FONT COLOR="#0000EE"><a href="http://www.public.asu.edu/~cmbarton/files/grass_gismgr/">http://www.public.asu.edu/~cmbarton/files/grass_gismgr/</a></FONT></FONT><FONT FACE="Lucida Grande, Verdana, Helvetica, Arial">gism_rc4_20060307pre_02-21.tgz></FONT><FONT FACE="Verdana, Helvetica, Arial"> <BR>
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</FONT><FONT FACE="Lucida Grande, Verdana, Helvetica, Arial"> Enjoy</FONT><FONT FACE="Verdana, Helvetica, Arial"> <BR>
</FONT><FONT FACE="Lucida Grande, Verdana, Helvetica, Arial"> Michael</FONT><FONT FACE="Verdana, Helvetica, Arial"> <BR>
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______________________________ <BR>
Michael Barton, Professor of Anthropology <BR>
School of Human Evolution and Social Change <BR>
Arizona State University <BR>
Tempe, AZ 85287-2402 <BR>
USA <BR>
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voice: 480-965-6262; fax: 480-965-7671 <BR>
www: <FONT COLOR="#0000EE"><a href="http://www.public.asu.edu/~cmbarton">http://www.public.asu.edu/~cmbarton</a></FONT> <BR>
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</FONT></SPAN></BLOCKQUOTE><SPAN DEFANGED_STYLE='font-size:12.0px'><FONT FACE="Verdana, Helvetica, Arial">> <BR>
> <BR>
What happens if a big asteroid hits Earth? Judging from realistic simulations involving a sledge hammer and a common laboratory frog, we can assume it will be pretty bad. <BR>
- Dave Barry <BR>
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</FONT></SPAN></BLOCKQUOTE><SPAN DEFANGED_STYLE='font-size:12.0px'><FONT FACE="Verdana, Helvetica, Arial"><BR>
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___________________________ <BR>
Michael Barton, Professor of Anthropology<BR>
School of Human Evolution & Social Change<BR>
Arizona State University<BR>
Tempe, AZ 85287<BR>
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WWW - <a href="http://www.public.asu.edu/~cmbarton">http://www.public.asu.edu/~cmbarton</a><BR>
Phone: 480-965-6262<BR>
Fax: 480-965-7671<BR>
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