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Re: Map transparent image [message #35679]

Tue, 01 July 2003 12:50

Haje Korth
Messages: 651
Registered: May 1997

Senior Member

Step two was what I needed to figure out: Alpha blending was the answer.

Thanks,
Haje

"Andy Loughe ( remove OMITs )" <Andrew.LougheOMIT@noaaOMIT.govOMIT> wrote in
message news:3F019EC8.2030608@noaaOMIT.govOMIT...
> Can this be accomplished by...
>
> (1) preparing the image to be created, like via map_set.
> (2) using polyfill or another technique to draw the (lightly colored)
mask.
> (3) "overplotting" with the data values included, then adding
> continents, grids, etc.
>
> ... or maybe your needs are more complex than this.
>
>
> Haje Korth wrote:
>> Good morning everyone,
>> I am trying to overlay a grey-shaded mask over an image to indicate
areas
>> where sample data are less reliable. However, I want the grey shaded
area to
>> be transparent so that I can still see the underlying data points. I do
not
>> want to use 'contour' since the results look rather confusing; too many
>> patches. As far as I can see, the IDL map_image command does not provide
>> such settings. Does anyone know, how the mask can be worked into the
image
>> prior to display? What is the math that one would apply?
>>
>> Thanks for helping,
>> Haje
>>
>>
>
>
> --
> Andrew Loughe =====================================================
> NOAA/OAR/FSL/AD R/FS5 | email: Andrew.Loughe@noaa.gov
> 325 Broadway | wwweb: www-ad.fsl.noaa.gov/users/loughe
> Boulder, CO 80305-3328 | phone: 303-497-6211 fax: 303-497-6301
>

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[Message index]

		Re: Map transparent image By: Haje Korth on Tue, 01 July 2003 12:50
		Re: Map transparent image By: Haje Korth on Tue, 01 July 2003 12:49
		Re: Map transparent image By: Haje Korth on Tue, 01 July 2003 12:43
		Re: Map transparent image By: David Fanning on Tue, 01 July 2003 12:51
		Re: Map transparent image By: mmiller3 on Tue, 01 July 2003 12:22
		Re: Map transparent image By: Andy Loughe ( remove on Tue, 01 July 2003 07:46
		Re: Map transparent image By: David Fanning on Tue, 01 July 2003 11:12
		Re: Map transparent image By: Haje Korth on Tue, 01 July 2003 10:45
		Re: Map transparent image By: David Fanning on Tue, 01 July 2003 08:26
		Re: Map transparent image By: Haje Korth on Tue, 01 July 2003 08:04
		Re: Map transparent image By: David Fanning on Tue, 01 July 2003 06:24

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