TheMarex / deberg

Map simplification using the deberg algorithm

DeBerg

This project implement a variation of the DeBerg line simplification algorithm.

The algortithm enables you to simplify lines without introducing self-intersections. You can also define an additional set of points that will stay consitent with regard to the line simplification: They will not change the 'side' of the line (e.g. when simplifying country borders cities will not suddently be in different countries).

This variation always computes the strongest simplification possible using the fewest edges.

Building

All dependencies (other than boost) should be included in third_party/.

mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make

Running

./deberg MAX_NUMBER_EDGES lines.txt points.txt output_lines.txt

Will write the result in output_lines.txt and print number of used edges in the console.

Input format

osm-admin-bounds is a tool to generate the input data from OpenStreetMap data.

You can use utils/data_to_geojson.py to convert files to geojson for easy visualization.

lines.txt

id:graphml_string

Example:

1:<gml:LineString srsName="EPSG:54004" xmlns:gml="http://www.opengis.net/gml"><gml:coordinates decimal="." cs="," ts=" ">-7984749.593824852,5368675.690126911 -7984392.035620423,5367570.791302501 -7983220.843257783,5366848.500158152</gml:coordinates></gml:LineString>

points.txt

id:graphml_string

Example:

115:<gml:Point srsName="EPSG:54004" xmlns:gml="http://www.opengis.net/gml"><gml:coordinates decimal="." cs="," ts=" ">-7878323.0399299,5218629.93044479 </gml:coordinates></gml:Point>

output.txt

Same format as lines.txt.