Am 05.12.2012 12:18, schrieb GerdP:
Henning Scholland wrote
So there are several cases:
1: several distinct areas in oneinput-file (eg Iceland and Germany or France and all there islands) -> splitter should stop and ask the user to use al polygon-file or create a polygon-file itself and warn user, that h did so
2: Map crossing 180/-180 -> split bounding-box at 180/-180 and calculate tiles for each of the two bounding-boxes
2a: Map crossing 180/-180, but covers hole planet as input -> use bounding-box left=-180 right=180 Yes, there are many cases, but it is not always easy for splitter to find out what the user did to create the input file. Splitter doesn't "know" that Europe exists and how many nodes it should find in that area. This could be changed if we always feed splitter with a file containing the densityMap for planet, but that wouldn't make it much easier to find out what tiles the user wants.
Reg. "create a polygon-file" : A possible algorithm for that could try to find bounding boxes that are not too big and have nice aspect ratio. It would prefer areas with few nodes to areas that are very big.
I am not sure if this is good enough, but I think it's worth trying. OK?
Hmm...for splitter my case 1 and 2 seems to be the same. He don't know what world continues on the other side of 180/-180. I think the density-map of splitter is like a table and each field contains the node-density for n° x n°. Then splitter adds them to eg. 1° x 1°-Tiles. If there is a density of zero, remove this tile. I don't know if 1° x 1° is a good value, it's just an example. It should be big enough, that also deserts have a density > 0. Splitter can now create a simple bounding polygon. This wont be perfect, but it's a starting-point. Also splitter should ask the user to improve the poly-file for better results. Henning