[ gpsdrive ] NOAA charts

[Chris h]

On Thursday 12 March 2009 03:45:57 Hamish wrote:
> [cropping off chart collars for auto-tile creation from BSB RNCs]

A basic test in an effort to keep things simple, I used qgis to play 
around with a converted BSB to tif. Observations follow;

1. grab suitable shape file of NA and overlay with tiff.
2. checked properties>colorbands 
3. made black and white pixels transparent
4. really screws up the chart..:) 

So what does this tell me? 

Well simply making specific bands/pixels transparent is not going to work. It 
will be needed to physically remove the border, which surprises me as if you 
zoom in on some of the lower resolution NOAA charts on demo.geogarage you can 
see the outline of chart as a very faint black line. You have to look for it 
but its there. 

Charts snippets visuals are available here 
http://chrish.selfip.com/gpsdrive/noaa/

-- 
/ch