Stephen,<br><br>Thanks for the tip. I believe your approach may set the shape layer to be transparent, letting lower layers to show through. However, I am trying to get the pixels in the final composited image to be completely transparent.<br>
<br><br clear="all">Glenn Waldron : Pelican Mapping : <a href="http://pelicanmapping.com">http://pelicanmapping.com</a> : +1.703.652.4791<br>
<br><br><div class="gmail_quote">On Wed, Feb 4, 2009 at 10:57 PM, Stephen Woodbridge <span dir="ltr"><<a href="mailto:woodbri@swoodbridge.com">woodbri@swoodbridge.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">gwaldron wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I'm trying to use IMAGECOLOR to try to force all pixels of a certain color to<br>
become fully transparent, but I am not having any luck getting it to work.<br>
<br>
My output format it AGG/PNG, RGBA, TRANSPARENT ON.<br>
<br>
I have a shapefile layer set to COLOR 0 50 100, and my map-level IMAGECOLOR<br>
set to the same. I was hoping all the polys in the shapefile would render as<br>
transparent pixels, but no luck; they just show up as blue polygons.<br>
<br>
What am I doing wrong here? Thanks.<br>
</blockquote>
<br></div>
Transparency is tricky indeed. I always have to experiment with setting to get it to work. I should document it for my one good, next time I work it out. Which doesn't really help you, but you might try the following.<br>
<br>
COLOR -1 -1 -1<br>
<br>
or leaving the COLOR off totally on a polygon should prevent it from filling, You probably want to use OUTLINECOLOR to cause it to draw the polygon border.<br>
<br>
Or are you trying to draw a color the will overwrite the pixels below it and make them transparent?<br>
<br>
-Steve W<br>
</blockquote></div><br>