[GRASS-user] r.sun and XY locations

[christian.braun at tudor.lu]

Hi Daniel,
it's clear to me that r.sun needs some sort of spatial reference.
I thought that is why I can provide latitude and longitude grids as input 
for the very special case of an XY location. Isn't it like that?

cheers
Christian
_________________________________________

Christian Braun,
R+D Engineer
Environmental Modelling, Geocomputation

Tel: +352- 425991-6608
Mobil: +49-179-6845896
Mail: christian.braun at tudor.lu

Resource Centre for Environmental Technologies,
Public Research Centre Henri Tudor,
Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg



From:   Daniel Lee <lee at isi-solutions.org>
To:     Christian Braun <Christian.Braun at tudor.lu>, 
Cc:     grass-user at lists.osgeo.org
Date:   08/08/2012 17:44
Subject:        Re: [GRASS-user] r.sun and XY locations



Hi Christian,

Determining the position of the sun relative to a given pixel requires 
knowing the pixel's latitude at the very least. That's why using r.sun in 
an XY location won't work. r.sun definitely needs a geographic location to 
work with - otherwise it doesn't know which way is north and south and 
where the sun's at at a given time of day or year.

Best,
Daniel
--
B.Sc. Daniel Lee
Geschäftsführung für Forschung und Entwicklung
ISIS - International Solar Information Solutions GbR
Vertreten durch: Daniel Lee, Nepomuk Reinhard und Nils Räder
Softwarecenter 3
35037 Marburg
Festnetz: +49 6421 379 6256
Mobil: +49 176 6127 7269
E-Mail: Lee at isi-solutions.org
Web: http://www.isi-solutions.org



2012/8/8 Christian Braun <Christian.Braun at tudor.lu>
Dear all,

I want to create a WPS module which is calculating solar irradiance. As 
WPS architecture I have to use PyWPS which is creating a XY-location and 
mapsets on the fly to process the data.

What is the current status of running r.sun in a XY location? On a testing 
machine I got back an error message [1] while providing latitude and 
longtiude grids to the r.sun command [2]. Is it feasible at all?

I am aware of the setting in PyWPS to have the GRASS processing done in a 
predefined GRASS location, but this is not an option because of how the 
WPS should work.

Greetings from Luxembourg,
Christian



[1]
WARNING: <PROJ_INFO> file not found for location <XY>
ERROR: Can't get projection info of current location

[2]
r.sun -s elevin=ro_dsm latin=ro_latitude longin=ro_longitude lin=3 
alb=0.17 beam_rad=ro_irra_B_hc diff_rad=ro_irra_D_hc glob_rad=ro_irra_G_hc 
day=180 step=1


------------------------------------------------------------
Christian Braun
R+D Engineer
Environmental Modelling, Geocomputation

Tel: +352- 425991-6608
Mobil: +49-179-6845896
Mail: christian.braun at tudor.lu

Resource Centre for Environmental Technologies,
Public Research Centre Henri Tudor,
Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg

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