Re: [Talk-GB] Building with mapseg
On 29 May 2010 20:31, TimSC mapp...@sheerman-chase.org.uk wrote: Hi all, I have updated the code and put out a new version of mapseg (now v0.2). As Roy Jamison discovered, the previous version was broken by upper case filenames. The program is now case insensitive to that. Available here: http://wiki.openstreetmap.org/wiki/Mapseg Is there an easy way to find the tile reference for a given area. I have found what I need so far by trial and error, but with 400 tiles it can be a bit of a pain. -- Philip Stubbs ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] Building with mapseg
Is there an easy way to find the tile reference for a given area. I have found what I need so far by trial and error, but with 400 tiles it can be a bit of a pain. -- Philip Stubbs Philip, A quick sketch on the method to go from tile filename to coordinates. Say we use the filen//ame su85se.tiff. The su part, the 85 part and the se part each give a different northing and easting offset. The must be summed to get the final bottom left corner position. The first offset is basically coarse grid letter offset and is found in a look up table. The codes are arranged like this: http://en.wikipedia.org/wiki/File:National_Grid_for_Great_Britain_with_central_meridian.gif The 85 is an intermediate offset, I think it is 8x1 metres east and 5x1 metres north. The final code can be se, sw, ne, nw for a fine tile offset. The n sheets are offset north by 5000m. The e sheets are offset east by 5000m. Each tile is 5000m by 5000m, as far as I remember so you can get the coordinates of the other corners. Re-reading your question, I guess you really want the inverse of what I just described? I hope that helps a little anyway. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Building with mapseg
On 1 June 2010 15:43, TimSC mapp...@sheerman-chase.org.uk wrote: Is there an easy way to find the tile reference for a given area. I have found what I need so far by trial and error, but with 400 tiles it can be a bit of a pain. -- Philip Stubbs Philip, A quick sketch on the method to go from tile filename to coordinates. Say we use the filename su85se.tiff. The su part, the 85 part and the se part each give a different northing and easting offset. The must be summed to get the final bottom left corner position. The first offset is basically coarse grid letter offset and is found in a look up table. The codes are arranged like this: http://en.wikipedia.org/wiki/File:National_Grid_for_Great_Britain_with_central_meridian.gif The 85 is an intermediate offset, I think it is 8x1 metres east and 5x1 metres north. The final code can be se, sw, ne, nw for a fine tile offset. The n sheets are offset north by 5000m. The e sheets are offset east by 5000m. Each tile is 5000m by 5000m, as far as I remember so you can get the coordinates of the other corners. Re-reading your question, I guess you really want the inverse of what I just described? I hope that helps a little anyway. TimSC Thanks Tim. I had worked out that there was some logic to the tile numbers. Having downloaded the tiles for SU, I wanted to find the tile that contained Warsash. Each tile only covers a small area, so I opened tiles until I recognised an area. Then I tried others near that one to see which way they went. Now I have found Warsash, I can work my may through that tile and the ones beside it with ease. I really asked the question for when or if others start to use the tiles also. Regards, -- Philip Stubbs ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Building with mapseg
Hi all, Just tested the raw output of this, and (without being flamed) have uploaded a few of these tile outputs to OSM on the Isle of Sheppey. Don't worry guys I have every intention of checking the entire island as I live here anyway, so will check alignments, etc. It is in my opinion as the only heavily active local local to the island that some buildings are better than none, and I did scan through the output briefly in JOSM and it looked extremely good!! The problem I'm having is with the SV data and mapseg. In particular the TR06NE.tif and TR06NW.tif tiles. For some strange reason, the .osm output files from mapseg are shifted to Faversham, about 5-10 miles south of where they should be. Any idea how to rectify this as I'm not too good with python. Thank you :) ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] Building with mapseg
Hi all, I have updated the code and put out a new version of mapseg (now v0.2). As Roy Jamison discovered, the previous version was broken by upper case filenames. The program is now case insensitive to that. Available here: http://wiki.openstreetmap.org/wiki/Mapseg I also considered the problem of importing buildings into an area already containing building data. We obviously don't want overlaps. I created a python script to remove duplicate buildings before uploading. This enables building imports into partially mapped areas and also incremental imports. (Details on the wiki.) Roy has been importing data in his area, it will probably take weeks to polish that data! Good luck with that! In my experience, about 10% of polygons are incorrect but flagged by the mapseg program for correction. The remaining 90% are pretty good but not as good as doing it manually, of course. http://www.openstreetmap.org/?lat=51.43458lon=0.764zoom=15layers=0B00FTF Here is an area I have imported and manually refined to be correct with OS street view: http://www.openstreetmap.org/?lat=51.26083lon=-0.61877zoom=17layers=B000FTF And here is an area I imported and corrected based on the surrey air survey. http://www.openstreetmap.org/?lat=51.2455lon=-0.59884zoom=17layers=0B00FTF So many options to choose from... TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
