Difference between climate data and Radiance data.

radiance-general
1

Dear all,

I’m going to study distribution of solar radiation in buildings in the city
by using GIS data.

I’d like to match a climate data with Radiance data. But, I couldn’t get
the same value.

Does anyone know the idea how to match climate data and Radiance data?

My method is below.

Obtain an illuminance by using Pvalue command.

views file is below.

rview rvu -vtl -vp 0 0 10 -vd 0 0 1 -vu 0 1 0 -vv 180 -vh 180 -vo 0.0 -va
0.0

skies file is below.

!gensky 6 22 5:0 -B 46 -R 37.12796503 -a 43.035 -o -141.199 -m -135.0

skyfunc glow skyglow

0

0

4 1.000 1.000 1.000 0

skyglow source sky

0

0

4 0 0 1 180

skyfunc glow groundglow

0

0

4 0 0 0 0

groundglow source ground

0

0

4 0 0 -1 180

bash file is below.

pvalue -h -H -d t1_1.pic | total -m | rcalc -e '$1=($1+$2+$3)/3*16'>t1.dat

The result is below.

time ND*1 Altit*2 HD*3=R B*4 no
Gensky -i -u

4:00 0 0.278 0 7
4.0464 9.4688 8.9056

5:00 225 9.498 37.12796503 46
25.44 52.128 58.368

6:00 445 19.824 150.9137426 76
43.12 75.744 96.752

7:00 588 30.608 299.3870167 82
51.872 79.744 104.256

8:00 636 41.547 421.8169494 108
82.752 112.752 137.504

9:00 618 52.252 488.6593632 151
149.504 190.56 192.48

10:00 557 61.986 491.7378991 220
295.04 371.04 279.04

11:00 519 68.96 484.3982757 264
451.04 590.08 335.04

12:00 459 69.842 430.8843623 300
534.08 694.08 380.96

13:00 395 63.995 355.0085362 348
495.04 625.92 443.04

14:00 532 54.691 434.1369031 207
220.48 276.96 263.04

15:00 397 44.127 276.411698 219
176.48 236.48 279.04

16:00 442 33.203 242.0423097 160
104.752 156.496 203.52

17:00 164 22.352 62.36849428 132
75.744 129.504 167.52

18:00 35 11.887 7.209375721 62
34.128 67.744 78.752

9:00 0 2.249 0 7
3.976 9.032 8.9056

*1: Normal direct solar radiation

*2: Horizontal direct solar radiation

*3: Solar altitude

*4: Horizontal total solar radiation

Best regards,

Hiroaki

2

Dear Hiroaki,

Although I am not sure what you are attempting to match or how you are doing so, but I can at least say that your view file is probably wrong.

The "-vtl" option specifies a parallel view, when you no doubt want a hemispherical projection ("-vth") in this case.

Best,
-Greg

···

From: 濱田裕章 <[email protected]>
Subject: [Radiance-general] Difference between climate data and Radiance data.
Date: April 30, 2014 12:28:19 AM PDT

Dear all,

I’m going to study distribution of solar radiation in buildings in the city by using GIS data.

I’d like to match a climate data with Radiance data. But, I couldn’t get the same value.

Does anyone know the idea how to match climate data and Radiance data?

My method is below.

Obtain an illuminance by using Pvalue command.

views file is below.

rview rvu -vtl -vp 0 0 10 -vd 0 0 1 -vu 0 1 0 -vv 180 -vh 180 -vo 0.0 -va 0.0

skies file is below.

!gensky 6 22 5:0 -B 46 -R 37.12796503 -a 43.035 -o -141.199 -m -135.0

skyfunc glow skyglow

0

0

4 1.000 1.000 1.000 0

skyglow source sky

0

0

4 0 0 1 180

skyfunc glow groundglow

0

0

4 0 0 0 0

groundglow source ground

0

0

4 0 0 -1 180

bash file is below.

pvalue -h -H -d t1_1.pic | total -m | rcalc -e '$1=($1+$2+$3)/3*16'>t1.dat

The result is below.

time ND*1 Altit*2 HD*3=R B*4 no Gensky -i -u

4:00 0 0.278 0 7 4.0464 9.4688 8.9056

5:00 225 9.498 37.12796503 46 25.44 52.128 58.368

6:00 445 19.824 150.9137426 76 43.12 75.744 96.752

7:00 588 30.608 299.3870167 82 51.872 79.744 104.256

8:00 636 41.547 421.8169494 108 82.752 112.752 137.504

9:00 618 52.252 488.6593632 151 149.504 190.56 192.48

10:00 557 61.986 491.7378991 220 295.04 371.04 279.04

11:00 519 68.96 484.3982757 264 451.04 590.08 335.04

12:00 459 69.842 430.8843623 300 534.08 694.08 380.96

13:00 395 63.995 355.0085362 348 495.04 625.92 443.04

14:00 532 54.691 434.1369031 207 220.48 276.96 263.04

15:00 397 44.127 276.411698 219 176.48 236.48 279.04

16:00 442 33.203 242.0423097 160 104.752 156.496 203.52

17:00 164 22.352 62.36849428 132 75.744 129.504 167.52

18:00 35 11.887 7.209375721 62 34.128 67.744 78.752

9:00 0 2.249 0 7 3.976 9.032 8.9056

*1: Normal direct solar radiation

*2: Horizontal direct solar radiation

*3: Solar altitude

*4: Horizontal total solar radiation

Best regards,

Hiroaki

3

Hiroaki,

I agree with Greg that it's not clear what you're doing, but I'm assuming
that you're using the climate data to create a sky file and then comparing
the horizontal direct illuminance to horizontal direct calculated from
solar angle and the climate data.

Integrating over pixels of a rendering is a round about way of getting at
illuminance. There's also potential error introduced by the pixel
resolution of the sun in the image. To address this you should make your
images very large (~4000x4000 pixels). Also I think you want to multiply
the result by 4, not 16, in your rcalc command (you have to multiply by
4/pi to counter the effect of the black edge pixels and also multiply by pi
as part of your hemisphere integration - pi cancels and the 4 remains).
This plus fixing your view as Greg suggests should give agreement.

You might consider instead using rtrace with -I+ (capital i) and -ab 1 like
so:

rtrace -h -I+ -ab 1 -aa 0 -ad 10000 -lw 1e-5 sky.oct

Also gendaylit is probably a better option than gensky for creating a sky
from a weather file. Gensky will give agreement in this test, but the sky
generated won't as valid as one generated by gendaylit.

Best,
Andy

···

On Fri, May 2, 2014 at 12:39 PM, Greg Ward <[email protected]> wrote:

Dear Hiroaki,

Although I am not sure what you are attempting to match or how you are
doing so, but I can at least say that your view file is probably wrong.

The "-vtl" option specifies a parallel view, when you no doubt want a
hemispherical projection ("-vth") in this case.

Best,
-Greg

*From: *濱田裕章 <[email protected]>

*Subject: *[Radiance-general] Difference between climate data and
Radiance data.

*Date: *April 30, 2014 12:28:19 AM PDT

Dear all,

I’m going to study distribution of solar radiation in buildings in the
city by using GIS data.

I’d like to match a climate data with Radiance data. But, I couldn’t get
the same value.

Does anyone know the idea how to match climate data and Radiance data?

My method is below.

Obtain an illuminance by using Pvalue command.

views file is below.

rview rvu -vtl -vp 0 0 10 -vd 0 0 1 -vu 0 1 0 -vv 180 -vh 180 -vo 0.0 -va
0.0

skies file is below.

!gensky 6 22 5:0 -B 46 -R 37.12796503 -a 43.035 -o -141.199 -m -135.0

skyfunc glow skyglow

0

0

4 1.000 1.000 1.000 0

skyglow source sky

0

0

4 0 0 1 180

skyfunc glow groundglow

0

0

4 0 0 0 0

groundglow source ground

0

0

4 0 0 -1 180

bash file is below.

pvalue -h -H -d t1_1.pic | total -m | rcalc -e '$1=($1+$2+$3)/3*16'>t1.dat

The result is below.

time ND*1 Altit*2 HD*3=R B*4 no
Gensky -i -u

4:00 0 0.278 0 7
4.0464 9.4688 8.9056

5:00 225 9.498 37.12796503 46
25.44 52.128 58.368

6:00 445 19.824 150.9137426 76
43.12 75.744 96.752

7:00 588 30.608 299.3870167 82
51.872 79.744 104.256

8:00 636 41.547 421.8169494 108
82.752 112.752 137.504

9:00 618 52.252 488.6593632 151
149.504 190.56 192.48

10:00 557 61.986 491.7378991 220
295.04 371.04 279.04

11:00 519 68.96 484.3982757 264
451.04 590.08 335.04

12:00 459 69.842 430.8843623 300
534.08 694.08 380.96

13:00 395 63.995 355.0085362 348
495.04 625.92 443.04

14:00 532 54.691 434.1369031 207
220.48 276.96 263.04

15:00 397 44.127 276.411698 219
176.48 236.48 279.04

16:00 442 33.203 242.0423097 160
104.752 156.496 203.52

17:00 164 22.352 62.36849428 132
75.744 129.504 167.52

18:00 35 11.887 7.209375721 62
34.128 67.744 78.752

9:00 0 2.249 0 7
3.976 9.032 8.9056

*1: Normal direct solar radiation

*2: Horizontal direct solar radiation

*3: Solar altitude

*4: Horizontal total solar radiation

Best regards,

Hiroaki

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

4

Thank you for your reply.

My view file was wrong. And it was a simple mistake.
Though I should have turned a viewpoint below, I took an upswing.

I'd like to study the distribution of solar radiation.
As a result of having noticed a mistake, I could get good result as follows.
1. Got parallel view by Radiance.
2. Picked original data by pvalue.
3. Calculated solar radiation (W/m2) by (R+G+B)/3*4*0.8
The value I got was same as the value that I input in gensky command.
But I did not know why it was necessary to multiply 0.8.
Someone, please tell me.

Best regards,

Hiroaki

···

2014-05-03 6:07 GMT+09:00 Andrew McNeil <[email protected]>:

Hiroaki,

I agree with Greg that it's not clear what you're doing, but I'm assuming
that you're using the climate data to create a sky file and then comparing
the horizontal direct illuminance to horizontal direct calculated from
solar angle and the climate data.

Integrating over pixels of a rendering is a round about way of getting at
illuminance. There's also potential error introduced by the pixel
resolution of the sun in the image. To address this you should make your
images very large (~4000x4000 pixels). Also I think you want to multiply
the result by 4, not 16, in your rcalc command (you have to multiply by
4/pi to counter the effect of the black edge pixels and also multiply by pi
as part of your hemisphere integration - pi cancels and the 4 remains).
This plus fixing your view as Greg suggests should give agreement.

You might consider instead using rtrace with -I+ (capital i) and -ab 1
like so:

rtrace -h -I+ -ab 1 -aa 0 -ad 10000 -lw 1e-5 sky.oct

Also gendaylit is probably a better option than gensky for creating a sky
from a weather file. Gensky will give agreement in this test, but the sky
generated won't as valid as one generated by gendaylit.

Best,
Andy

On Fri, May 2, 2014 at 12:39 PM, Greg Ward <[email protected]> wrote:

Dear Hiroaki,

Although I am not sure what you are attempting to match or how you are
doing so, but I can at least say that your view file is probably wrong.

The "-vtl" option specifies a parallel view, when you no doubt want a
hemispherical projection ("-vth") in this case.

Best,
-Greg

*From: *濱田裕章 <[email protected]>

*Subject: *[Radiance-general] Difference between climate data and
Radiance data.

*Date: *April 30, 2014 12:28:19 AM PDT

Dear all,

I’m going to study distribution of solar radiation in buildings in the
city by using GIS data.

I’d like to match a climate data with Radiance data. But, I couldn’t get
the same value.

Does anyone know the idea how to match climate data and Radiance data?

My method is below.

Obtain an illuminance by using Pvalue command.

views file is below.

rview rvu -vtl -vp 0 0 10 -vd 0 0 1 -vu 0 1 0 -vv 180 -vh 180 -vo 0.0 -va
0.0

skies file is below.

!gensky 6 22 5:0 -B 46 -R 37.12796503 -a 43.035 -o -141.199 -m -135.0

skyfunc glow skyglow

0

0

4 1.000 1.000 1.000 0

skyglow source sky

0

0

4 0 0 1 180

skyfunc glow groundglow

0

0

4 0 0 0 0

groundglow source ground

0

0

4 0 0 -1 180

bash file is below.

pvalue -h -H -d t1_1.pic | total -m | rcalc -e '$1=($1+$2+$3)/3*16'>t1.dat

The result is below.

time ND*1 Altit*2 HD*3=R B*4 no
Gensky -i -u

4:00 0 0.278 0 7
4.0464 9.4688 8.9056

5:00 225 9.498 37.12796503 46
25.44 52.128 58.368

6:00 445 19.824 150.9137426 76
43.12 75.744 96.752

7:00 588 30.608 299.3870167 82
51.872 79.744 104.256

8:00 636 41.547 421.8169494 108
82.752 112.752 137.504

9:00 618 52.252 488.6593632 151
149.504 190.56 192.48

10:00 557 61.986 491.7378991 220
295.04 371.04 279.04

11:00 519 68.96 484.3982757 264
451.04 590.08 335.04

12:00 459 69.842 430.8843623 300
534.08 694.08 380.96

13:00 395 63.995 355.0085362 348
495.04 625.92 443.04

14:00 532 54.691 434.1369031 207
220.48 276.96 263.04

15:00 397 44.127 276.411698 219
176.48 236.48 279.04

16:00 442 33.203 242.0423097 160
104.752 156.496 203.52

17:00 164 22.352 62.36849428 132
75.744 129.504 167.52

18:00 35 11.887 7.209375721 62
34.128 67.744 78.752

9:00 0 2.249 0 7
3.976 9.032 8.9056

*1: Normal direct solar radiation

*2: Horizontal direct solar radiation

*3: Solar altitude

*4: Horizontal total solar radiation

Best regards,

Hiroaki

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general