On Jul 30, 2008, at 6:53 AM, <[EMAIL PROTECTED]> wrote:
Date: Wed, 30 Jul 2008 15:53:50 +0200
From: "Markus Neteler" <[EMAIL PROTECTED]>
Subject: Re: [GRASS-user] Re: import a folder full of shapefiles and
reproject on-the-fly?
To: "Tim Michelsen" <[EMAIL PROTECTED]>
Cc: [email protected]
Message-ID:
<[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1
Hello Tim,
On Tue, Jul 29, 2008 at 11:41 PM, Tim Michelsen
<[EMAIL PROTECTED]> 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 script :) Could 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.proj
Not 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
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