Exporting calibrated maps

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This page is being considered for cleanup. Please discuss this page.

Information on Calibration

gis data need to be assoicate with calibrate information. Those information are

  • the datum
  • the projection
  • the coordinate formats
  • the geographic extents, ie :
    • either the coordinates of the upper left corner and the pixels sizes
    • either the coordinates of the upper left corner and of the lower right corner

Because embedding calibration in raster can't be explicit view read , people must use a tool like gdalinfo to be able to read text information.gdalinfo could be find in GDAL . GDAL (Geospatial Data Abstraction Library) is a library for reading and writing raster geospatial data formats.

install this two tools ( gdalinfo,tool) in the same directory to be able to read the calibration information .Another way is to use gdal commandline as describe here after install FWTools (22.5 Mo)

Exporting calibrated maps from OSM

It should be possible to export calibrated maps from OSM servers. The map could be a raster (Tiles) or projection or vector files. This would make it quick and easy for someone to actually use OSM in their device and software of choice.

No. Please don't perpetuate this. The "Google Mercator" projection (Mercator on a sphere using the WGS84's major radius of the Earth's ellipsoid, but ignoring the minor axis) used in the Slippy Map are not appropriate for use with a real GIS. It is only useful for low load on a visual map server. Instead, import the raw OSM XML data downloaded with e.g. Xapi and converted into a GIS vector format with a program like gpsbabel. Probably the best solution is to load the OSM Planet file extract into a PostGIS database and work from there. The EPSG has bowed to pressure and against its own better judgment issued a projection code for Google Merc, but that does not mean it is legitimate for serious use. For more there's a bit of a fuzzy discussion in the Osmarender bug wiki page, or better hear what the professional geodisists have to say over on the PROJ.4 mailing list, try the search terms "google+abomination".

A raster uncalibrate map can be easely downloaded using openstreetmap slippyMap by using the Export tab and select [renderers] (osmrenderer, manik) and output raster (JPEG, PNG).

To get a calibrated map use either taho.pl and taho.exe

This is slightly complicated by the wide range of calibration file formats. The Taho Programs produce 5 different formats, but there are a few conversion programs around (see below) which suggests these should all be fairly interchangeable.

Calibration file formats

The following list is incomplete. Please add any other formats you know of[1].

translation software

step for calibrate a raster file

Before a scanned map can be displayed in the correct location, it needs to be calibrated (geo-referenced). This process involves specifying the location of two or three known points on the map. Once the correct geographic coordinates are known for these points (called Calibration Points), a calibrate software can calculate the coordinates of every other point on the map. Every calibrate software need specific requirements:

  • The map must be in a specific raster format : JPEG, TIFF, PNG, BMP... format (compress, 24-32 bits/color).
  • The map must be oriented so that North is up. If the North arrow is more than 45 degrees from vertical, you will need to rotate the map before proceeding.
  • You need to know the projection used to create the map. This information is usually printed at the bottom or in the margin of the map.

The calibration process step is to associate waypoint ( calibration point) from GPX to some wellknow waypoint in the raster file .

There are two ways to enter a calibration point.

  • If your map has a grid overlay, you can click the Calibration Point tool on the grid intersection, and enter the coordinates of that grid intersection. If you already have waypoints for known features on the map (trailheads, summits, a road intersection) you can use them

Two calibration points are generally sufficient to geo-reference a topo map or nautical chart. If the lines of longitude on your map are not perfectly vertical, or if your map is rotated, you may need a third calibration point to correct for the rotation.

Your scanned map is now calibrated and ready for use. The next time you want to view GPS data over this map, click Show Scanned Map on the View menu.

If the map is a subset of a big map that come from a server , some tool can do all the work for you if you enter only the url of the server and the bounding box ( in a gui or script way). The tool manage calibration, merge raster graphic tiles and export all in one or two files .

Calibration software

There are many calibrations softwares ( All professional gis software do this). Those kind of software are mainly use for navigate in area where there is no road [3]:

software natively compatible with OSM

  • NoniMapView a must have for oziexplorer ( *.map *.jpeg only )
  • OSM-map is a software that support map/ raster output file from OSM server
  • OSMtiledownloader
  • manifold GIS
  • perl script
  • QGIS appear in version 0.7.4 Menu plugin / géoréférenc...and include since 1.1 even you can use grass . Read documentation here
  • gvSIG read the details documentation in french here
  • Taho available as perl-script or Windows program. Both can create Maps with different Calibration Files for areas of any size.

calibrate software not directly compatible with OSM

this software could be use after having calibrate file as converter for PC/mobile GPS software.

Calibration conversion programs


  • OziMapConverter - converts to and from various formats, for use with Oziexplorer.
    • Converts .jpr, .rsf, .gmw, .gcp, .prc, .cal, .cap, .geo, .cpt, .map


  • MAPC2MAPC - freeware
    • Converts .MAP (Ozi), .JPR (Memory-map, Fugawi), .GMI (GPSTuner), .GUX (GPSU), .MCD (GPSMAPOS, GPSGO), .CAL (Pathaway), .TFW (Mapyx/Quo). Will handle different input datums but always writes WGS84.

MAPC2MAPC is a program to calibrate maps and convert calibration files for digital maps from one format to another. Will read and write MAP (Ozi), JPR (Memory-map, Fugawi), GMI (GPSTuner), GUX (GPSU), MCD (GPSMAPOS, GPSGO), CAL (Pathaway), TFW (Mapyx/Quo). Will also crop and re-size calibrated maps whilst retaining the calibration. Will handle different input datums but always writes WGS84. More information in the readme file.

The software is provided 'as is' without warranty. It is free to download and use for personal or commercial purposes.

Note that this program only converts calibration files that are held alongside image files - it will not convert maps in a proprietory format such as Memory-map's .qct files.

Similar projects

Other sites can be used for specific programs, e.g. OSM to TrekBuddy at http://osm.bandnet.org/browse/?2030,1318,12,1

Doing it the hard way - http://faq.walkingworld.com/afmmain.aspx?faqid=67

See also