San Vicente map MapGazer – MGMaps map format


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The MGMaps map format was originally developed for a smartphone application (Mobile GMaps) but is now used by a number of applications, including MapGazer and MyTrails.  For information on downloading maps in this format, see Getting maps.

Maps displayed by MapGazer are composed of tiles – images that are 256 by 256 pels (pixels, or picture elements) using a coordinate system originally developed for Google Maps and now widely used by other map sources including Open Street Map, the Ordnance Survey, and other mapping organisations.

Each map has one or more zoom levels, or layers which can present a view of the map appropriate for the zoom level.  Zoom level 0 is the least detailed (it presents almost the entire globe in one tile) whereas (for example) 1:25,000 topographical maps are typically presented at zoom level 15 or 16.

MGMaps collects tiles together into files on disk, usually with 64 tiles in a file.  The files for each layer are held in a folder which in turn is inside a folder that names the map (the map base folder). The base folder also contains a file named cache.conf which must be present for the folder to be accepted as an MGMap format map. This contains the (maximum) number of tiles per file, and also may have copyright information† for the map.

More information about the format can be found here, and a copy of the nutiteq specification of the format (© 2008 Nutiteq LLC) is here.


† The copyright information is a MapGazer addition to the base MGMaps specification; it is an extra line added to the cache.conf file of the form: copyright=data, for example:

    copyright=© OpenStreetMap contributors

MapGazer and these web pages were written by Mike Cowlishaw; Please send me any corrections, suggestions, etc.
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This page was last updated on 2016-05-29 by mfc.