El Lunes, 14 de Septiembre de 2009, Ian Dees escribió: > This feature could be added, but could you draw a couple pictures to > explain what you mean? What happens with the graph edges inside the > multipolygon? Since they aren't really polygons, do they belong in a > multipolygon relation? Maybe I'm not correctly interpreting what you meant.
OK, let's do some crapy ASCII-art. So set your e-mail readers to a fixed-width font. Suppose a .osm file containing the following polygons and nodes. Suppose that the polygons are originally ways. n4-------------------------n3-------------------n2---n1 | | | | | | | P1 | | | | | | | n6----n5 | | | | n11--n10 | n19 P4 | | P2 | | | P3 | n7 | n12---n9 | | | n8 | | | n18--n17---n16-------n15---------n14------------n13 | | | | | P5 | | | n21-----------------------n20------------------n19 For every pair of connected nodes (segment i.e. graph edges), relate that segment to a set of one or two polygons. Any adjacent segments related to the same set of polygons gets converted into a way (i.e. simplified graph edges): n4-AAAAAAAAAAAAAAAAAAAAAAAA-n3-BBBBBBBBBBBBBBBB--n2-E-n1 | | | | A H F P1 E A H | | A H n6-E-n5 A | | | n11-C-n10 G n19 | | | | C P3 D n7 A P4 | | P2 G A n12-DD-n9 G A I n8 | I G n18-J-n17-J-n16-JJJJ-n15-KKKKKKK-n14-KKKKKKKKKK-n13 | | L L L P5 L | | n21-LLLLLLLLLLLLLLLLLLLLL-n20-LLLLLLLLLLLLLLLL-n19 So this creates ways as follows: A = n3-n4-n19-n18 B = n3-n2 C = n10-n11-n12 D = n10-n9-n12 E = n2-n1-n5-n6 F = n2-n6 G = n6-n7-n8-n13 H = n3-n10 I = n12-n15 (Please note H and I are both adjacent to both P4 and P2, but are different ways as they're not adjacent segments. Same goes to B and G.) J = n18-n17-n16-n15 K = n15-n14-n13 L = n18-n21-n20-n19-n13 And then, given those, the algorithm destroys the original polygons-as-ways and reconstructs them as relations: P1 = E-F P2 = B-H-D-I-K-G-F P3 = C-D P4 = A-H-C-I-J P5 = J-K-L I think I make myself clear with those. Of course, if the inputs are multipolygons, the algorithm gets a little more complex, but the idea stays the same: *Any polygons that share at least one segment with another polygon should get converted into a relation of polygon edges*. I would like to be able to convert and fix stuff properly... not to speak about those JOSM warnings about polygon ways sharing a segment. P.S.: Remind me to take a course in computational geometry. I'm feeling like I need it. Cheers, -- ---------------------------------- Iván Sánchez Ortega <i...@sanchezortega.es> Aviso: Este e-mail es confidencial y no debería ser usado por nadie que no sea el destinatario original. No se permite la reproducción mediante fotocopia, walkie-talkie, emisora de radioaficionado, satélite, televisión por cable, proyector, señales de humo, código morse, braille, lenguaje de signos, taquigrafía o cualquier otro medio. Bajo ningún concepto debe traducirse al francés este e-mail. Este e-mail no puede ser ridiculizado, parodiado, juzgado en una competición, o leído en voz alta con un acento gracioso llevando un bigote falso y/o cualquier tipo de sombrero, incluyendo pero no limitándose a pañuelos. No inciten ni provoquen a este e-mail. Si está medicándose, puede experimentar nauseas, desorientación, histeria, vómitos, pérdida temporal de la memoria a corto plazo y malestar general al leer este e-mail. Consulte a su médico o farmacéutico antes de leer este e-mail. Todas las modelos descritas en este e-mail son mayores de 18 años. Si ha recibido este e-mail por error es probablemente porque estaba borracho cuando escribí la dirección del destinatario. _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
