On Jul 30, 2008, at 6:53 AM, <grass-user-request@lists.osgeo.org> wrote:
Date: Wed, 30 Jul 2008 15:53:50 +0200
From: "Markus Neteler" <neteler@osgeo.org>
Subject: Re: [GRASS-user] Re: import a folder full of shapefiles and
reproject on-the-fly?
To: "Tim Michelsen" <timmichelsen@gmx-topmail.de>
Cc: grass-user@lists.osgeo.org
Message-ID:
<86782b610807300653j48a077a9u50248468a699e319@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1Hello Tim,
On Tue, Jul 29, 2008 at 11:41 PM, Tim Michelsen
<timmichelsen@gmx-topmail.de> wrote:
...Nevertheless, I cannot get around expressing my disappointment about
GRASS in this area.
* I cannot just point the program to a directory of shapefiles and tell
it import all. QGIS, gvSIG and ArcGIS can do this.We could easily add v.in.ogr.all or v.external.all, I suppose two or
three lines of shell scriptCould be stored in the Addons wiki.
* I cannot reproject these on the fly be changing the projection of my
location.Yes, because it was decided to not support that (see archive of this list).
And, using QGIS I regularly *fail* to do this job.=> Whenever it comes to data format conversion and reprojection people
on QGIS/GRASS Maillists tend to tell the user: get your keyboard and
hack something with OGR/GDAL (Re: converting .asc to .xyz,
http://permalink.gmane.org/gmane.comp.gis.qgis.user/2519).
In clear words this means that the software is not ready, yet.I don't agree. You can easily import and reproject single maps even
with the various d.m/gis.m/wxpython user interfaces:
- create new location *graphically* from startup menu, now even with
location wizard.
- run r/v.projNot too much keyboard needed here.
This tells me that these GIS are not made for "normal" Desktop GIS task
and mapping.
Maybe GRASS is good for some very specialised and automatisable tasks.
But to make a beautiful and printable map from a buch of data that can
be interpreted?see
http://grass.osgeo.org/wiki/WxPython-based_GUI_for_GRASS#Cartography_tools
-> work in progress...
Why did I write disappointment? Because GRASS is advertised by OSGEO as
THE most powerful free GIS that can perform any task.Where did you see "any task"?
This is a good reply. No GIS software that I know of is good at everything. ArcGIS has great cartographic tools, but is limited for processing raster files. GRASS can make very nice looking maps (I've published some in leading journals), but lacks easy cartographic layout (that is, it has the tools but they are not point and click). However, it's raster processing is superb and easy.
There has been a lot of discussion about on-the-fly reprojection. The consensus from experience with programs that offer it is that it is very convenient for making maps for display, but very problematic for any uses that require geospatial precision. GRASS has chosen to implement projection protocols and algorithms that ensure accuracy. It also supports an enormous array of projections.
Combining gdal with a large array of additional internal drivers, GRASS can import and export more GIS formats than any other program I know of. Importing a directory full of ESRI shape files is a task that some people encounter, but many more do not. If there is enough demand for this, someone will end up writing a module or script that everyone in the community can use. That's one of the great things about open source GIS.
While often a response will reference a GRASS module by name (e.g. r.in.gdal), all can be used via GUI interfaces and almost all are accessible from the main GRASS GUI. Suggestions that suggest to 'get your keyboard and hack something' usually are pointing out that if a fuction is not already built into GRASS, a user can create his/her own pretty easily. With most GIS software, what you see is what you get and what you are stuck with. As a Mac user, I'm a big fan of GUI's--to such an extent that it might annoy my colleagues on the development team at times ;-). Nevertheless, I'm also an equally big fan of GRASS's enormous flexibility and ease of creating scripts that combine GRASS commands in new ways. By way of a couple personal example, GRASS has no inherent way of creating a graphic output file of one of its displays. So the first script I ever wrote, combined GRASS commands to create that function. While there are now various ways of achieving this, the descendent of that script (d.out.file) is still useful to many. My research team has created one of the most sophisticated and fastest landscape dynamics modeling tools that I've seen or read of--capable of simulating erosion/deposition over centuries and across watersheds of millions of cells in response to climate and vegetation change. We did it simply by chaining together GRASS commands in scripts.
GRASS is not good for any task. But it is very useful for many of the tasks involved in the processing, analysis, and display of geospatial data. In comparison with other similar software--and there are many good packages and some not so good ones--it's as 'prime time' as it gets.
Michael