Better Text results when exporting GIS data in raster form to Google Map API

[iskinner]

I am very new to the world of GIS data. We are planning on exporting a large custom map (2 million square miles) of recreational information for the North Central Sierra Nevada mountain range.

With the help of the fine folks at Global Mapper, our cartographer and I have been able to export a test section of map data from his ArcGIS 9.2 as a GeoTIFF file that I was able to parse into Google Map Tiles with Global Mapper.

We are now experimenting with various levels and types of transparency effects to see what presents our data blended with Google's data to the best effect. This can be seen at the URL: Map Tests (Google Maps Export from Global Mapper).

I'm liking the 'no white' version were I had Global Mapper make the white background of the GeoTIFF transparent. One of the few negatives about this is the lettering. The letters that where anti-aliased to a white background in the GeoTiff file now have a halo effect around them.

Can anybody here provide some simple hints or guidelines to myself and|or the cartographer on how we could mitigate this halo effect and improve the look of the lettering with a transparent background?

TIA
Ian

[global_mapper]

Ian,

Can you provide a screenshot of what exactly the halo effect that you are talking about looks like?

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[iskinner]

Can you provide a screenshot of what exactly the halo effect that you are talking about looks like?

http://www.sierraoutdoorrecreation.c...alo_effect.png

I've linked to an image and uploaded an image of this halo affect. As you can see there is a light border around the letters where the font had been blended (anti-aliased) to the original white background of the map. Against the darker background of the Google terrain map, it stand out as a halo around the letters.

TIA
Ian

[global_mapper]

Ian,

Ok, I see. When you make white transparent, also check the box to 'Make Similar Colors Transparent' and see if that makes any difference.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[iskinner]

When you make white transparent, also check the box to 'Make Similar Colors Transparent' and see if that makes any difference.

That is the option I selected to produce the example previously presented. I presume the 'whites' weren't close enough.

Ian

[global_mapper]

Ian,

Yeah, I guess what you are seeing is the part of the anti-aliasing that is too far from actual white. I guess you could actually think of the halos as a positive as they will make the text visible regardless of what color the underlying data is.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com