[gradsusr] Combining two shaded variables.

[Chorley Weather]

On 07-08-2015 13:19, Stephen McMillan wrote:
> Hi,
> I don't quite follow what you're trying to do, since your last two
> sample lines appear precisely the same.  Bottom line, for it to work:
> 
> - Display first variable, save it
> - Clear, then display second variable, then save it with previous
> saved map as the background and a specified transparent color
> -To add a third variable, clear, then display the third variable, then
> save it with the second saved map as background and specified
> transparent color
> -And so on
> 
> If above is not addressing your problem then, to properly diagnose it,
> it would help for you to send the appropriate lines of your code that
> you are using.  Also, which version of GrADS are you using?
> Stephen Mc
> 
> On Fri, Aug 7, 2015 at 5:33 AM, Chorley Weather
> <weatherstu at chorleyweather.com> wrote:
> 
>> On 05-08-2015 19:31, Stephen McMillan wrote:
>> 
>> Jose, Stuart,
>> 
>> Jeff's recommendation for 2.1+ and the alpha channel is probably
>> the
>> best way to go since you can control the transparency/opaqueness,
>> but
>> here's a sample script if you don't have or don't want to upgrade.
>> Cloud clover with precip overlay sample attached, along with script
>> that created it.
>> 
>> Good luck!
>> Stephen Mc
>> 
>> On Wed, Aug 5, 2015 at 1:36 PM, Jeff Duda <jeffduda319 at gmail.com>
>> wrote:
>> 
>> Upgrade to version 2.1+ and use the alpha channel when creating
>> colors.
>> 
>> Jeff
>> 
>> On Wed, Aug 5, 2015 at 12:15 PM, Chorley Weather
>> <weatherstu at chorleyweather.com> wrote:
>> 
>> On 05-08-2015 16:09, Stephen McMillan wrote:
>> Stuart,
>> 1. Display first variable then save to an image file
>> 2. Clear screen, then display second variable
>> 3. Save to another file using first file as background (-b
>> option)
>> and specify an appropriate transparent color (-t option)
>> 
>> Resulting saved map should be without the rough, pixelated
>> edges
>> 
>> Stephen Mc
>> 
>> On Wed, Aug 5, 2015 at 10:04 AM, Chorley Weather
>> <weatherstu at chorleyweather.com> wrote:
>> 
>> Hi guys,
>> 
>> I have been trying to combine two shaded variables in one
>  image,
> 
>>> for
>>> example precip & cloud cover. I have tried the maskout
>  function but
> 
>>> the
>>> output looks to rough and pixelated. Can anybody suggest a
>  better
> 
>>> way to
>>> get a smoother result.
>>> 
>>> Many thanks in advance
>>> Stuart.
>>> 
>>> --
>>> Chief Forecaster & Owner
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>>> gradsusr at gradsusr.org
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>> 
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>  Thanks Stephen, I will have a go at that cheers.
>  --
>  Chief Forecaster & Owner
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> 
>  --
> 
>  Jeff Duda
>  Graduate research assistant
>  University of Oklahoma School of Meteorology
>  Center for Analysis and Prediction of Storms
> 
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>  Hi Stephen,
> 
>  The sample script you sent has worked well with my own variables as
> shown in the attached image. The problem I have is the output image
> keeps replacing the previous image, ie. my printim is
> 
>  'printim pcpn-cldcvr.png x1100 y675 -b gfs_ukcloudcover1'i'.png  -t
> 0';#overlay/save 2nd variable on previous image, black as transparent.
> 
>  How do i script it were i get    printim pcpn-cldcvr1.png x1100 y675
>                                   printim pcpn-cldcvr2.png x1100 y675
>                                   printim pcpn-cldcvr2.png x1100 y675
>  And so on.
> 
>  --
>  Chief Forecaster & Owner
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>  gradsusr at gradsusr.org
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> 
> 
> 
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Hi Stephen,
The last sample line was supposed to be 3.png (typo). I'm using 
opengrads and the code is thus:


   i = 3
   while ( i<maps )

* Set up a few preliminary characteristics
setmap(1)
setSMcols(1)
'set t 'i

*'define dew  = const((dewpt(tmp2m,rh2m)-273.16),0,-u)'
'set gxout shaded'
'set csmooth on'
'set clevs 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100'
'set ccols 0 63 62 61 60 59 58 57 56 55 54 53 52 51 50 47 46 45 44 43 42 
41 17 39 38 37 36 35 34 33'

'd tcdcclm'

'cbar'
'printim gfs_ukcloudcover1'i'.png x1100 y675';#1st (backgrd) image

'c'

setstucols(1)
'set t 'i
'set gxout shaded'
'set csmooth on'
'set clevs 0.2 0.5 1.5 2 3 4 5 6 7 8 9 10 13 16 19 22 25 30 35 40 45 50 
60 70 80 90 100'
'set ccols 0 43 44 45 46 47 48 49 39 38 37 36 35 33 22 23 24 25 26 27 28 
29 67 66 65 64 63 62 61'

'd apcpsfc'

'printim pcpn-cldcvr.png x1100 y675 -b gfs_ukcloudcover1'i'.png  -t 
0';#overlay/save 2nd variable on previous image, black as transparent


i = i+1
endwhile

Like I said the output image just re writes over the last, so I only 
ever have 1 image. I should be getting 80+ images. Thanks for your 
advice.

regards,
Stuart
-- 
Chief Forecaster & Owner