Details Ticket 3826


Comment | Reply | Take | Resolve


Serial Number 3826
Subject two r.resamp.rst issues
Area grass6
Queue grass
Requestors hamish_nospam@yahoo.com
Owner none
Status open
Last User Contact Sun Nov 13 20:29:46 2005 (3 yr ago)
Current Priority 20
Final Priority 70
Due No date assigned
Last Action Mon Nov 14 00:09:40 2005 (3 yr ago)
Created Sat Nov 12 13:37:05 2005 (3 yr ago)

Transaction History Ticket 3826


Sat, Nov 12 2005 13:37:05    Request created by hbowman  
Subject: two r.resamp.rst issues

If you run r.resamp.rst at a resolution other that that of the input map, the
output elev map is not created at the specified ew_res= and ns_res= resolution.
A warning is given that you are doing so, but it doesn't mention why that
might be bad. Interestingly the output map is actually written at the target
resolution, but it contains the data resolution from the original map. (target
was 50m, original was 100m)

If the input map is in another mapset (map@othermapset) then it gives an error
that the input map can't be found. (happens when it tries to copy the color
table I think) and exits with an error. (but processing is already done so
output map is ok, just without a colortable)


Hamish


ps - I've tidied up the module's code and strings a bit in CVS, so cvs update
before fixing...
Sun, Nov 13 2005 20:29:46    Mail sent by michael.barton@asu.edu  
Return-Path <Michael.Barton@asu.edu>
Delivered-To grass-bugs@lists.intevation.de
Date Sun, 13 Nov 2005 12:27:50 -0700
From Michael Barton <michael.barton@asu.edu>
Subject Re: [GRASS5] [bug #3826] (grass) two r.resamp.rst issues
In-reply-to <20051112123705.4EE111005CD@lists.intevation.de>
To Paolo Cavallini via RT <grass-bugs@intevation.de>, grass5@grass.itc.it
Message-id <BF9CE1C6.6A44%michael.barton@asu.edu>
MIME-version 1.0
Content-type text/plain; charset=US-ASCII
Content-transfer-encoding 7bit
User-Agent Microsoft-Entourage/11.2.1.051004
Thread-Topic [GRASS5] [bug #3826] (grass) two r.resamp.rst issues
Thread-Index AcXoiFWklEpScFR7EdqlwgAKlW/i4A==
X-Spam-Status No, hits=-4.9 tagged_above=-999.0 required=3.0 tests=BAYES_00
X-Spam-Level
Hamish,

We've run into that here too. One of my RA's did a test of interpolating to
a higher resolution using r.resamp.rst and the more complicated procedure of
generating a large number of points from a raster map, and then
interpolating from the points to a higher resolution.

r.resamp.rst is faster and more straightforward. BUT (a VERY big but), it
behaves exactly as you describe. It simply turns out a map that looks just
like the original map is subdivided into more grid cells, without any
interpolation. This makes the module essentially useless.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton



> From: Request Tracker <grass-bugs@intevation.de>
> Reply-To: Request Tracker <grass-bugs@intevation.de>
> Date: Sat, 12 Nov 2005 13:37:05 +0100 (CET)
> To: <grass5@grass.itc.it>
> Subject: [GRASS5] [bug #3826] (grass) two r.resamp.rst issues
> 
> this bug's URL: http://intevation.de/rt/webrt?serial_num=3826
> -------------------------------------------------------------------------
> 
> Subject: two r.resamp.rst issues
> 
> If you run r.resamp.rst at a resolution other that that of the input map, the
> output elev map is not created at the specified ew_res= and ns_res=
> resolution.
> A warning is given that you are doing so, but it doesn't mention why that
> might be bad. Interestingly the output map is actually written at the target
> resolution, but it contains the data resolution from the original map. (target
> was 50m, original was 100m)
> 
> If the input map is in another mapset (map@othermapset) then it gives an error
> that the input map can't be found. (happens when it tries to copy the color
> table I think) and exits with an error. (but processing is already done so
> output map is ok, just without a colortable)
> 
> 
> Hamish
> 
> 
> ps - I've tidied up the module's code and strings a bit in CVS, so cvs update
> before fixing...
> 
> 
> -------------------------------------------- Managed by Request Tracker
> 
> 
> 


Mon, Nov 14 2005 00:09:40    Mail sent by hamish_nospam@yahoo.com  
Return-Path <hamish_nospam@yahoo.com>
Delivered-To grass-bugs@lists.intevation.de
Date Mon, 14 Nov 2005 12:09:12 +1300
From Hamish <hamish_nospam@yahoo.com>
To Michael Barton via RT <grass-bugs@intevation.de>
Cc Jaro Hofierka <hofierka@geomodel.sk>, Helena Mitasova <hmitaso@unity.ncsu.edu>, grass5@grass.itc.it
Subject Re: [bug #3826] (grass) two r.resamp.rst issues
Message-Id <20051114120912.4ffdd964.hamish_nospam@yahoo.com>
In-Reply-To <20051113192947.012BF1006C1@lists.intevation.de>
References <20051113192947.012BF1006C1@lists.intevation.de>
X-Mailer Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-pc-linux-gnu)
X-Face M<EoB)"*Z~u!,vFhXmw}R_KbdBta*P_=T|rbBL'e1/CQ9;/1g\BU3&!=y8ria$2Uk!HT&BB 8i?|X_+7~1jsy}F~g$2va%3fV`*=L(*cem[@3\yg,G,@rg6/QMJ
Mime-Version 1.0
Content-Type text/plain; charset=US-ASCII
Content-Transfer-Encoding 7bit
X-Spam-Status No, hits=-4.0 tagged_above=-999.0 required=3.0 tests=BAYES_00, FORGED_YAHOO_RCVD
X-Spam-Level
> this bug's URL: http://intevation.de/rt/webrt?serial_num=3826
> ---------------------------------------------------------------------
> Subject: two r.resamp.rst issues
> 
> If you run r.resamp.rst at a resolution other that that of the input
> map, the output elev map is not created at the specified ew_res= and
> ns_res= resolution.
> A warning is given that you are doing so, but it doesn't mention why
> that might be bad. Interestingly the output map is actually written at
> the target resolution, but it contains the data resolution from the
> original map. (target was 50m, original was 100m)
> 
> If the input map is in another mapset (map@othermapset) then it gives
> an error that the input map can't be found. (happens when it tries to
> copy the color table I think) and exits with an error. (but processing
> is already done so output map is ok, just without a colortable)
> 
> 
> Hamish
> 
> 
> ps - I've tidied up the module's code and strings a bit in CVS, so cvs
> update before fixing...


Michael wrote:
> We've run into that here too. One of my RA's did a test of
> interpolating to a higher resolution using r.resamp.rst and the more
> complicated procedure of generating a large number of points from a
> raster map, and then interpolating from the points to a higher
> resolution.
> 
> r.resamp.rst is faster and more straightforward. BUT (a VERY big but),
> it behaves exactly as you describe. It simply turns out a map that
> looks just like the original map is subdivided into more grid cells,
> without any interpolation. This makes the module essentially useless.

Jaro wrote:
> It's not useless because if you run the module at a resolution equal
> to  the input raster map, the result is OK.
> The warning message should be replaced by a fatal error that exits the
> command.

Ok, done in 6.1-cvs, but would a better long term fix be to address why
the region switching code alreadyt in the module doesn't take care of
this for you automatically? Maybe the first thing the module needs to do
is switch to the input map's resolution (internally). Perhaps that is
not in line with the way most other GRASS raster modules work so should
be avoided?


The colortable error in IL_resample_output_2d() is still there.
(G_open...() needs to be one of the other G__open..() fns so the mapset
isn't stripped off at the "map exists" check, or the mapset that is
returned from the G_open..() function needs to be passed to IL_resam..()
?? I may have my fn names wrong, but the fix should be along those
lines.)


Hamish


Comment | Reply | Take | Resolve

You are currently authenticated as guest.
[Show Configuration] [Login as another user]

Users Guide - Mail Commands - Homepage of RequestTracker 1.0.7 - list any request