wiki:GSoC_gdal2ogr_api

Version 1 (modified by kedron, 15 years ago) ( diff )

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Project:

gdal2ogr API in libgdal

Student:

Kedron Touvell me@…

Mentor:

Tim Keitt

Abstact:

This project will extend the gdal2ogr library and add APIs that take raster data as input and output vector data (and possibly vice versa). The simplest conversion is from raster (with implicit x, y cordinates) to a point coverage (x, y, z). The next simplest would be to output square polygons one-per-pixel (a set of four points x1 y1, x2 y2, x3 y3, x4 y4 plus a single z value). After that we could do larger rectangles where the z-value is the average or another statistic computed on the pixels falling within the quadrangle. After that comes hexagonal grids with user specified width (resolution). After that (and possibly the most interesting) we will explore outputting various mesh representations (triangulations) of the surface. These are sometimes called TINs in the GIS lexicon.

Development Resources

Weekly Reports

Week 1 (ending June 5)

I got off to a slow start due to a time-consuming apartment move and a poorly-timed illness. Still, I fully expect that I can catch up in the next week or two. I've started by downloading the gdal source using svn and successfully built it in cygwin (I'm using the latest development branch - 1.70 - revision 17199). Cygwin is handy for me because my laptop is dual boot with Ubuntu, but my campus wireless network performance is slow in linux. I also found a number of open sourced, GPL raster to vector conversion software packages online that I'm currently investigating. I expect that I may be able to cannibalize some of that code for parts of this project.

Currently, I am not blocked with anything, though I am working with my mentor to get more input from the community on what specific conversion routines they would like to see. My biggest goal for the next week is to evaluate what existing code and algorithms are out there that can be re-used in libgdal for this API. Then I will begin testing for performance, etc.

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