[GRASS-dev] broken stuff in vector modules

Michael Barton michael.barton at asu.edu
Wed May 23 10:55:54 EDT 2012


Further efforts show that the distance upload is giving the correct value. I had the wrong flag checked (not as clear as it might be in the GUI). The other issues remain. But at least I CAN get useful analysis results.

Michael



On May 23, 2012, at 4:49 PM, <grass-dev-request at lists.osgeo.org>
 wrote:

> Send grass-dev mailing list submissions to
> 	grass-dev at lists.osgeo.org
> 
> To subscribe or unsubscribe via the World Wide Web, visit
> 	http://lists.osgeo.org/mailman/listinfo/grass-dev
> or, via email, send a message with subject or body 'help' to
> 	grass-dev-request at lists.osgeo.org
> 
> You can reach the person managing the list at
> 	grass-dev-owner at lists.osgeo.org
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of grass-dev digest..."
> Today's Topics:
> 
>   1. broken stuff in vector modules (Michael Barton)
>   2. another bug in v.distance (Michael Barton)
>   3. v.distance values bogus in GRASS 6.4.2 also (Michael Barton)
> 
> From: Michael Barton <Michael.Barton at asu.edu>
> Subject: [GRASS-dev] broken stuff in vector modules
> Date: May 23, 2012 4:43:11 PM GMT+02:00
> To: GRASS developers grass-developers <grass-dev at lists.osgeo.org>
> 
> 
> Hi,
> 
> I don't use the vector modules a lot and so they don't get a lot of testing from me. I'm trying to do a project with someone that uses vector module and I find that some key things are broken. The following apply to GRASS 7 and GRASS 6.4.3.
> 
> 1) v.distance gives bogus results for point to line distance uploads in a latlon region. For example, the distance uploaded from one site point to the nearest waterway is 5767967.05475, yet measuring this with the distance tool gives a much more reasonable 33211 m. The uploaded distance is off by an order of 173X -- an enormous error. Nothing in the docs says that you cannot use v.distance with latlon regions. 
> 
> 2) To get around this, I thought I'd try to get the length of the line that connects each site point with its nearest waterway (a v.distance option). But when I tried to make a new table for this in the table manager, I find that I cannot access the "table description" section of the "manage layers" page in the attribute table manager. This is again because wx.StaticBox needs to be defined in a particular order or the Mac interface cannot access it. This has been a recurrent problem with wx.StaticBox. The StaticBox must be instantiated before any of its contents. 
> 
> 3) After creating a linked table using v.db.addtable instead of the attribute manager, I tried to modify the layer in the attribute table manager, but only received a message that "<flag> is not a valid value". Another bug.
> 
> I did manage to get a length value into the lines connecting the points and they are quite reasonable values. But of course I have no way that I can see to link the distance lines back to the points from which they were created with v.distance. So I still don't have analysis results and my colleague is ready to try this in ArcGIS. 
> 
> Any suggestion for a workaround would be much appreciated. And of course, the multiple bugs here need to be fixed.
> 
> Michael
> 
> _____________________
> C. Michael Barton
> Visiting Scientist, Integrated Science Program
> National Center for Atmospheric Research &
> University Consortium for Atmospheric Research
> 303-497-2889 (voice)
> 
> Director, Center for Social Dynamics & Complexity 
> Professor of Anthropology, School of Human Evolution & Social Change
> Arizona State University
> www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
> 
> 
> 
> 
> 
> 
> 
> 
> From: Michael Barton <Michael.Barton at asu.edu>
> Subject: [GRASS-dev] another bug in v.distance
> Date: May 23, 2012 4:47:08 PM GMT+02:00
> To: GRASS developers grass-developers <grass-dev at lists.osgeo.org>
> 
> 
> Forgot to mention that the table selection pull-downs do not work in any version of the v.distance GUI--from 6.4.2 to 7.0
> 
> Michael
> _____________________
> C. Michael Barton
> Visiting Scientist, Integrated Science Program
> National Center for Atmospheric Research &
> University Consortium for Atmospheric Research
> 303-497-2889 (voice)
> 
> Director, Center for Social Dynamics & Complexity 
> Professor of Anthropology, School of Human Evolution & Social Change
> Arizona State University
> www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
> 
> 
> 
> 
> 
> 
> 
> 
> From: Michael Barton <Michael.Barton at asu.edu>
> Subject: [GRASS-dev] v.distance values bogus in GRASS 6.4.2 also
> Date: May 23, 2012 4:48:37 PM GMT+02:00
> To: GRASS developers grass-developers <grass-dev at lists.osgeo.org>
> 
> 
> So the values for point to line distances are just as bad in GRASS 6.4.2 as they are in GRASS 7. Any suggestions on how to get this information for a latlon region?
> 
> Michael 
> _____________________
> C. Michael Barton
> Visiting Scientist, Integrated Science Program
> National Center for Atmospheric Research &
> University Consortium for Atmospheric Research
> 303-497-2889 (voice)
> 
> Director, Center for Social Dynamics & Complexity 
> Professor of Anthropology, School of Human Evolution & Social Change
> Arizona State University
> www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
> 
> 
> 
> 
> 
> 
> 
> _______________________________________________
> grass-dev mailing list
> grass-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/grass-dev

_____________________
C. Michael Barton
Visiting Scientist, Integrated Science Program
National Center for Atmospheric Research &
University Consortium for Atmospheric Research
303-497-2889 (voice)

Director, Center for Social Dynamics & Complexity 
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu





-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/grass-dev/attachments/20120523/aa772194/attachment-0001.html


More information about the grass-dev mailing list