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Make background of raster transparent in illustrator?

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#1
Wombat

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Hi. This is probably just a newby dilemma.

I have a simple map that I exported from ArcGIS to Illustrator. The base layer is a hillshade raster. I made sure no layer in the ArcGIS document has any transparency to prevent rasterizing of unneeded layers. The graphic I want to create follows the shape of our regional county boundary. In other words, I want the border of our region to be the shape/extent of the map and the background to be transparent. The problem is that the area outside of the regional boundary is symbolized as white when I want it to be transparent. In Illustrator I can't isolate the hillshade image alone without the white background.

I have:
  • Made Sure that the background color of the map in ArcGIS is sett to null.
  • Tested the "Clip Output to Graphics Extent" option when exporting from ArcGIS.
  • Made sure the "Document Raster Effects Settings" for "Background" is set to "Transparent".
  • Tried treating a clipping mask around the boundary layer to "mask" away the white back ground (this didn't work - might be inexperienced mistake).
  • Exported the hillshade layer independently to both Illustrator and PNG format with NO success.

See Attached for example.

Any help making this white background would be awesome. Thank you in advance.

Justin

Attached Files



#2
razornole

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I would use photoshop for this application to delete all the contiguous white pixels and save it in a psd format. Then I would place this raster in Illy.

What is the final output of this map?

kru
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#3
Wombat

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I would use photoshop for this application to delete all the contiguous white pixels and save it in a psd format. Then I would place this raster in Illy.

What is the final output of this map?

kru



Thank you. That is what I ended up doing.

Is there a way to use a clipping mask to do this in Illustrator?

Justin

#4
Pete

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Is there a way to use a clipping mask to do this in Illustrator?

Justin


If you're exporting from ArcMap to .ai format you should be able to use your region shape to define a clipping mask for the raster. As long as you export to .ai with your raster at the bottom of the table of contents you won't rasterise any layers you don't want to - as you've said. What you'll need to do is make a copy of your region shape in the same layer as the hillshading then click the make/release clipping path button on the bottom of your layers palette (or the same option is in the layers palette's extra options menu). Thing to watch out for is that when you make your clipping path Illustrator will use whatever polygon is at the top of the layer or group where you're applying your mask.

#5
Pete

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Just thought - the only other way I think you might like to try out is to use a shape in ArcMap to define your dataframe shape.

If you right-click on your dataframe in layout view and then click properties, click on the dataframe tab and then click in the checkbox to enable chip to shape. If you click on the button to specify shape you can then chose from the layers that are in your table of contents.

The only thing I'd say against using this technique is that, in my experience, if your outline is the least bit complex ArcMap will freak out and take a long time to draw you map.

#6
Wombat

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That's great. I was able to make a clipping mask pretty easily after joining my fragmented boundary polygon. This is a great method for my work flow. I couldn't get the ArcGIS method to work. For some reason, no matter how I seem to configure the settings, the raster will not export with a transparent background or with a background as a separate layer from the actual hillshade. Regardless, the two other methods (Illustrator - Clipping Mask and Photoshop - Delete Area) work great.

Thanks again for all your help.

Justin




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