[mkgmap-dev] British National Grid and Latitude/Longitude

Thu Dec 13 10:28:35 GMT 2012

_British National Grid__
_
Some time ago I published an OSM format file for the British National 
Grid, as printed on Ordnance Survey maps.

I have now updated this. There are two main changes:
     1. The Way and Node IDs are now well out of the range of Open 
Street Map IDs, so the file can be processed simultaneously with other 
source files;
     2. By omitting roughly 50% of internal nodes, and some formatting 
changes, the (uncompressed) file size is reduced from about 73MB to 
about 20MB for the same coverage. This has negligible effect on the 
final output, since the grid lines are very close to straight lines over 
a few kilometres.

This file may be downloaded from http://www.rogercalvert.me.uk/OSM/GBGrid.

_Latitude and Longitude_

In a similar manner, I have generated a file of lines of Latitude and 
Longitude. But since these are world wide, rather than limited to Great 
Britain, I have put a generator on line at 
http://www.rogercalvert.me.uk/OSM/LatLong 
<http://www.rogercalvert.me.uk/OSM/LAtLong>. A file will be generated in 
real time and downloaded for any (sensible) range of coordinates. For 
performance reasons, I have limited the download size to 10MB (which is 
enough to cover mainland Great Britain), but several downloads may be 
used to cover a larger region.

Please let me know of any problems you encounter in accessing or using 
these.

Roger
-- 
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Roger Calvert
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