Hi list,
I am trying to use r.sun and have some problems understanding the results.
If I want the total irradiation in a specified day then I have to select the option 2. In this case I obtain the following maps:
- beam_rad: irradiation raster file
- insol_time: insolation raster map
- diff_rad: irradiation raster map
- refl_rad: irradiation raster map
So I don't understand a few things...
- where does GRASS save the irradiation raster file?
- what is the difference between the diff_rad irradiation raster map and the refl_rad irradiation raster map.
- I noticed that I have a raster map created with the name of the beam_rad "file", so I think in this case GRASS makes a raster and not a file, but what do these values means?
- which of these maps created whit the command gives to me the total radiation for the day? maybe I have to sum some of them but I don't understand which of them to take into account.
I am trying to use r.sun and have some problems understanding the
results. If I want the total irradiation in a specified day then I
have to select the option 2. In this case I obtain the following
maps: - beam_rad: irradiation raster file
- insol_time: insolation raster map
- diff_rad: irradiation raster map
- refl_rad: irradiation raster map
So I don't understand a few things...
..
- where does GRASS save the irradiation raster file?
it's not one output file, it's a raster map named whatever you gave the
beam_rad option. see below.
- what is the difference between the diff_rad irradiation raster map
and the refl_rad irradiation raster map.
one is diffuse light (think cloud scatter), the other reflected light
(glare bouncing off ground hitting hillside??).
- I noticed that I have a raster map created with the name of the
beam_rad "file", so I think in this case GRASS makes a raster and not
a file, but what do these values means?
yes, beam_rad mades a raster map, not some data file. This is already
changed in the development source code.
mode 2 units are Wh.m-2.day-1. Watt-hours per meter^2 per day.
- which of these maps created whit the command gives to me the total
radiation for the day? maybe I have to sum some of them but I don't
understand which of them to take into account.
total = beam + diffuse + reflected
(add with r.series)
PS: how do you use r.series? I thought to use r.mapcalc
Hamish wrote:
Silvia Franceschi wrote:
I am trying to use r.sun and have some problems understanding the
results. If I want the total irradiation in a specified day then I
have to select the option 2. In this case I obtain the following
maps: - beam_rad: irradiation raster file
- insol_time: insolation raster map
- diff_rad: irradiation raster map
- refl_rad: irradiation raster map
So I don't understand a few things...
..
- where does GRASS save the irradiation raster file?
it's not one output file, it's a raster map named whatever you gave the
beam_rad option. see below.
- what is the difference between the diff_rad irradiation raster map
and the refl_rad irradiation raster map.
one is diffuse light (think cloud scatter), the other reflected light
(glare bouncing off ground hitting hillside??).
- I noticed that I have a raster map created with the name of the beam_rad "file", so I think in this case GRASS makes a raster and not
a file, but what do these values means?
yes, beam_rad mades a raster map, not some data file. This is already
changed in the development source code.
mode 2 units are Wh.m-2.day-1. Watt-hours per meter^2 per day.
- which of these maps created whit the command gives to me the total radiation for the day? maybe I have to sum some of them but I don't understand which of them to take into account.
total = beam + diffuse + reflected
(add with r.series)
>> - which of these maps created whit the command gives to me the
>> total radiation for the day? maybe I have to sum some of them but
>> I don't understand which of them to take into account.
Thanks Hamish,
very useful command that I didn't know but I will try to use it instead of r.mapcalc in some cases.
Cheers
Silvia
Silvia:
- which of these maps created whit the command gives to me the
total radiation for the day? maybe I have to sum some of them but
I don't understand which of them to take into account.
Hamish:
[global] = beam + diffuse + reflected
(add with r.series)
Silvia:
PS: how do you use r.series? I thought to use r.mapcalc