[R-sig-Geo] make polygons transparent in plotKML

[Seth Bigelow]

I never was able to get the alpha= argument to create transparent polygons
in plotKML, but by carefully following the example in Bivand et al. (2008),
of Scotland's borders (Chap 4.2.1, using OGR drivers in rgdal) I was able to
achieve the desired effect. Thanks for problem-solving with me
-Seth


-----Original Message-----
From: MacQueen, Don [mailto:macqueen1 at llnl.gov] 
Sent: Thursday, April 18, 2013 5:53 PM
To: Seth Bigelow
Subject: Re: [R-sig-Geo] make polygons transparent in plotKML

Hmm. In that case I'd guess it's a package design and usage issue. But I'm
not very familiar with the package, so it is indeed just a guess.

?kml shows an example with alpha=0.75, so maybe we're not intended to call
plotKML directly, but rather through kml().

-Don

--
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 4/18/13 2:26 PM, "Seth Bigelow" <seth at swbigelow.net> wrote:

>Thanks for your assistance, however, I don't seem to be achieving 
>transparency no matter what alpha is...
>
>plotKML(MV[PSW,], colour_scale=rgb(0,0,0, alpha=0))   # Makes black fill
>
>
>--Seth
>
>
>-----Original Message-----
>From: MacQueen, Don [mailto:macqueen1 at llnl.gov]
>Sent: Thursday, April 18, 2013 3:21 PM
>To: Seth Bigelow
>Subject: Re: [R-sig-Geo] make polygons transparent in plotKML
>
>(actually, ?rgb would have been a better pointer)
>
>--
>Don MacQueen
>
>Lawrence Livermore National Laboratory
>7000 East Ave., L-627
>Livermore, CA 94550
>925-423-1062
>
>
>
>
>
>On 4/18/13 9:03 AM, "Seth Bigelow" <seth at swbigelow.net> wrote:
>
>>Greetings: 
>>
>> 
>>
>>Could anyone advise me how to make transparent polygons in plotKML? I 
>>am overlaying polygons in a SpatialPolygonsDataFrame object into 
>>Google Earth - Seems I can make the polygons any color (e.g., yellow - 
>>see
>>example) except transparent
>>
>> 
>>
>>plotKML(mySPDF, colour_scale ="#FFFF00")
>>
>> 
>>
>>Appreciately, Seth Bigelow
>>
>>
>>	[[alternative HTML version deleted]]
>>
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>
>