GSOC 2012 Vector Layer Generalization¶
This is a page for the Vector Layer Generalization project by a student from Russia. It contains brief weekly reports, for more detailed description please visit the blog http://blogs.gis-lab.info/ugnpaul/
Student¶
Evgeniy Pashentsev, Voronezh State University
Project description¶
The idea is to implement the topology preserving generalization algorithm, integrate on-the-fly generalization into the rendering and make any other possible improvements related to visualization and simplification.
Work plan¶
1. Implement generalization for a collection of objects keeping their topological relations. The Douglas-Peucker algorithm will be used.
2. Implement the on-the-fly generalization to speed up rendering. According to some tests, a simple distance threshold routine followed by the Douglas-Peucker algorithm shows significant reduction of the rendering time, especially with complex style lines.
3. Look into the render cache realization and find a way to improve it, if possible.
4. Adapt existing feature cache patch to the last QGIS version.
A more specific plan will be here soon.
Weekly report number one¶
Planned: make first steps of writing topology preserving generalization
Done: written a prototype of the simplification tool for a vector layer
Problems: actually this tool doesn't work as expected yet, but it just needs some debugging
Next week: get it to work
Details: http://blogs.gis-lab.info/ugnpaul/?p=8
Weekly report number two¶
Done: continued working on topology preserving simplification
Problems: multipart features, mistakes in segments assembling order
Next week: deal with current problems
Details: http://blogs.gis-lab.info/ugnpaul/2012/06/02/gsoc-2012-weekly-report-number-two/
Weekly report number three¶
Done: almost correct topology preserving simplification
Problems: simplification mistakes, too slow, no UI
Next week: make it usable
Details: http://blogs.gis-lab.info/ugnpaul/2012/06/10/gsoc2012-weekly-report-number-three/
Weekly report number four¶
Done: some kind of user interface
Problems: mistakes are still there, also performance is not very good
Next week: fix everything that is possible
Details: http://blogs.gis-lab.info/ugnpaul/2012/06/15/gsoc-2012-weekly-report-number-four/
Weekly report number five¶
Done: some refactoring
Problems: refactoring isn't finished yet
Next week: finish the tool
Details: http://blogs.gis-lab.info/ugnpaul/2012/06/23/gsoc-2012-weekly-report-number-five/
Weekly report number six¶
Done: refactoring is almost done
Problems: new algorithm should be tested
Next week: finish the tool
Details: http://blogs.gis-lab.info/ugnpaul/2012/06/30/gsoc-2012-weekly-report-number-six/
Weekly report number seven¶
Done: fixed some bugs
Problems: new algorithm brought new bugs
Next week: fix the rest, write unit tests
Details: http://blogs.gis-lab.info/ugnpaul/2012/07/07/gsoc-2012-weekly-report-number-seven/