OpenStreetMap is a website that offers map data for free. The website is owned by the openstreetmap foundation which exists to protect, promote, and support the project, but does not own the data. All data offered by OpenStreetMaps is offered under a Creative Commons license.
This document discusses how you can use this map data in the Eye4Gps GPS Mapping software. There are various ways to use the map data from the website, one of them is to export sections of the map as PNG or JPG images.
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To export a portion of the map data, just open your web browser and go to "http://www.openstreetmaps.org". If this is the first time you visit the site, a base map is presented. Using the mouse to center the map, and the mouse wheel to zoom in and out on the map, you can select the area you want to export. Click the "Export" tab on top of the map display to show the export options. To export part of the map as PNG file, select the "Mapnik Image" format and select either PNG or JPG as export format. Then click the "Export" button to create and download the map image. In this example this map is saved as "map.png". In the upper-left corner you will notice the export area, you are going to need this coordinates to calibrate the map, so we write down the coordinates of the upper-left and lower-right corners of the map:
LAT 52.2834 N, LON 6.6493 E LAT 52.1470 N, LON 6.8701 E
Now that you have saved the map data as an image, you can load the map into the Eye4Software GPS Mapping software. This can be done by selecting "File" => "Open" from the menu, and selecting the map file, for instance "map.png". The map will be loaded and a message box is displayed, to notify you that the map needs calibration, just ignore this message for now, and click the "OK" button.
To calibrate the map image, you have to open the "Map Calibration and Projection" window. To open this window, please select "File" => "Map Calibration" from the menu. We are going to calibrate the map by entering the coordinates of the map's boundaries, so click the "Bounds..." button first. The following dialog will appear:
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Now enter the upper-left and lower-right coordinates of the map, as displayed in the export area section of the OpenStreetMaps webpage (or the coordinates you have written down). Please note that the coordinates are in decimal format, you can set the input boxes to decimal latitude- and longitude format from the "Units Settings" window which can be accessed by clicking "Options" => "Preferences" menu option. Click "OK" when you are finished entering these coordinates.
The software will now create the calibration points for the 4 corners off the map, which are displayed in the list. Before calculating the calibration info, you have to set the map projection to be used. Click the "Projection" button, the Projection window will appear. You can set the projection by hand, or just load a predefined map projection. Click the "Load Predefined Map Projection" button, and select "Earth - World Mercator". This projection uses the Mercator projection on the WGS84 ellipsoid, which is the same projection as used by OpenStreetMaps. After you clicked "OK" twice, the "Map Calibration and Projection" window should look like this:
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To finish the calibration process, just click the "Calculate" button followed by the "Save" button. You are now ready to use the map, for instance to project your routes and waypoints on it.
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