distance between polygon

[brahim.boudamouz@…]

Distance between polygon return 0 whereas it is not.

For example, the following two polygons poly and poly2:

typedef boost::geometry::model::d2::point_xy<double> point_type; typedef boost::geometry::model::polygon<point_type> polygon_type;

polygon_type poly, poly2;

boost::geometry::read_wkt("POLYGON((0.483707939991215 4.773920582819078, 0.5053006295162502 4.848900310429359, 0.5026276157353238 4.926851374195881, 0.47595271806952655 5.000142970012212, 0.42788885209344396 5.061604949484321, 0.36314153156370255 5.1052282121312595, 0.28804795065446004 5.12675006676153, 0.20995692111385858 5.124068426945231, 0.13651026810181627 5.097445647190528, 0.07489571249838214 5.049482920409928, 0.031143980177505432 4.984867693057649, 0.009538656296549554 4.909917885067861, 0.012196499626267798 4.831966193462844, 0.03885948446609647 4.758643661998902, 0.0869192454259704 4.697132255323741, 0.151671837534352 4.653459953523097, 0.22677805366317155 4.63190817924884, 0.30488425540802405 4.634590447230228, 0.37834282146581616 4.661244162857866, 0.43996148046825034 4.709256316654202))", poly);

boost::geometry::read_wkt("POLYGON((-1.0557992498764188 4.746036929415318,-1.0993658333477525 4.810856267060861, -1.1608453480495324 4.859088577533509, -1.234220477005859 4.886019279588865, -1.312310562575837 4.889015578303403, -1.3874737831476758 4.867782698965993, -1.452354304963582 4.8243932756221835, -1.5006016515805882 4.763086838460696, -1.5274921589195156 4.689857989799479, -1.530391741605481 4.61187218939475, -1.5090144880022829 4.5367652713717845, -1.465451447333285 4.471894995746168, -1.4039664811460055 4.423618461729835, -1.3305789878636327 4.3966671418069225, -1.2524743477794593 4.393681706260662, -1.177299942608499 4.414952781113644, -1.1124158788230383 4.458393143311671, -1.0641739853613563 4.519743805317727,-1.0372958425476984 4.5929932717763435, -1.0344108128292469 4.670968207668558))",poly2);

std::cout << "distance: " << boost::geometry::distance(poly, poly2) << std::endl;

[anonymous]

stand alone c++ source code to test bug

[awulkiew]

Thanks for the report.

By default bg::model::polygon is clockwise and closed (the last point must be equal to the first one). On the other hand the polygons you defined in WKT are not. To fix it you may:

1. Pass closed WKTs
2. Call bg::correct() after reading the polygon from WKT
3. Use open polygon type, e.g. bg::model::polygon<point_type, true, false>

Can you confirm that this is not a bug?

[brahim.boudamouz@…]

In fact that is not a bug! A call of boost::geomery::correct(mypolygon) before computing distance solve the problem Thanks for your quick answer and problem handling Grateful for the time you spent