Splitting multipolygons
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Hi! I am using an alternate splitter (built into OSM Composer) to prepare tiles for processing with mkgmap. It works rather well, except when it comes to the splitting of polygons involved in multipolygon relations. A possible result of splitting is a large polygon split by a tile boundary into multiple smaller polygons all located in the same tile. These polygons all share the same id. The multipolygon relation is also contained in that tile. Mkgmap (r1067) processes these polygons in a weird way. Sometimes one of them is visible and the others are missing, sometimes the multipolygon relation seems to be inverted with the clearings being shown as wood and the wood missing. What is the expected strategy for splitting a polygon with multipoly relations into several parts within one tile? How does splitter handle this? Has there been some work around this area recently? bye Nop
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On 10/08/09 14:29, Nop wrote:
What is the expected strategy for splitting a polygon with multipoly relations into several parts within one tile? How does splitter handle this? Has there been some work around this area recently?
The patch I forwarded onto the list this morning was dealing with just such a problem. I've not looked at it fully yet. There are other outstanding mulitpolygon fixes that may help too. The first of which is applied to the multipolygon branch: https://svn.parabola.me.uk/svn/mkgmap/branches/multipolygon ..Steve
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Hi! Steve Ratcliffe schrieb:
On 10/08/09 14:29, Nop wrote:
What is the expected strategy for splitting a polygon with multipoly relations into several parts within one tile? How does splitter handle this? Has there been some work around this area recently?
The patch I forwarded onto the list this morning was dealing with just such a problem. I've not looked at it fully yet.
There are other outstanding mulitpolygon fixes that may help too. The first of which is applied to the multipolygon branch:
I am not sure I understand. Do maps split with splitter also have the problem of missing polygons at the moment? bye Nop
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On 10/08/09 15:07, Nop wrote:
There are other outstanding mulitpolygon fixes that may help too. The first of which is applied to the multipolygon branch:
I am not sure I understand. Do maps split with splitter also have the problem of missing polygons at the moment?
The splitter doesn't really know about multi polygons so there are no reasons I know why it should introduce any problems. It is just the way the work is shared between splitter and mkgmap. The splitter creates a rough oversized area and mkgmap does the difficult work of cutting the polygons to the exact boundary. ..Steve
participants (2)
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Nop
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Steve Ratcliffe