Re: [boost] Formal Review: Boost.Polygon starts today August 24, 2009

Subject: Re: [boost] Formal Review: Boost.Polygon starts today August 24, 2009
From: Phil Endecott (spam_from_boost_dev_at_[hidden])
Date: 2009-08-25 15:02:14

Dear Luke & others,

Congratulations on getting this library as far as a review.  I feared 
that the scope of the subject might make it impossible for anyone to 
ever get this far.  Perhaps we have Luke's employer to thank for this.

I hope to have time to try out the library with at least a couple of 
real-world examples.  I'll describe the problems that I have in mind 
now and update later with my experiences.

Marker Merging:  I have lots of small square markers indicating search 
results on a map.  If the map is zoomed out so that the whole planet is 
visible and you search for something common like "lake", it will 
attempt to draw many thousands of overlapping markers which is slow.  
Since the markers are just squares of solid colour, I would like to 
merge them into a single polygon-set and plot that.  Speed is the main 
concern.  It it also interesting to consider what would happen if the 
markers were circles.  Here's an example of the sort of output I need:  http://chezphil.org/tmp/six_thousand_lakes.jpeg

Border Simplification:  I have data describing state outlines as 
polygon-sets.  I want to pre-process that into a format that permits 
rapid rendering; specifically, I want to generate multi-resolution 
versions with smoothing and interpolation as necessary.  I also want to 
reduce it from polygons with common edges to polylines, so that each 
border is plotted once rather than twice.  This is something that 
happens off-line as part of a build process, so speed is much less 
important than ease of coding.  Example output:  
http://chezphil.org/tmp/state_borders.jpeg  (yes, it's an iPhone app... 
hey, we all have to pay the rent somehow...)

Regards,  Phil.

p.s. has anyone worked out where this thread has gone on gmane.org?