• Introduction
• Web based map
• Configuration file
• First simple example
• Other uses
• File based map
• Configuration file
• Where to get tiles for a file based map?
• Syntax of a configuration file
• Section [Tiled MAP]
• Variables
• Referenced sections
• Character encoding
• More examples

Introduction

January 14th, 2009: This feature is now available in the official version of gpsVP (from version 0.4.16).

Through configuration files it is possible to define new raster maps in gpsVP. This can be used in two ways:

• For a web based map, i.e. to access a map which is on a web server. It’s a map like the ones which already exists in gpsVP (OpenStreetMap, ...).
• For a file based map, i.e. a map where all the parts are stored in files. It can be a map which you downloaded on your PC, a scanned map, ...

Web based map

Configuration file

For a web based map gpsVP will download parts of the map when needed. The parts ("tiles") are then stored in a cache, exactly like for the already existing maps.

• Each map should have its own configuration file.
• The configuration files should be stored in a subfolder MapConfigs with the executable (i.e. probably \Program files\gpsVP\MapConfigs if gpsVP is installed directly on the device).
• The file extension must be ini. The file name is free but will be reused to create a subdirectory in the cache and will be displayed in the map menu.
• The map configurations are loaded during the start of gpsVP. You need to restart gpsVP after adding or editing configurations.

First simple example

Create a text file called OpenStreetMapViaIni.ini in the MapConfigs with the following text:

[Tiled MAP]
gpsVPVersionMin=0.4.16
Filename=x=%X&y=%Y.png
URL=http://tile.openstreetmap.org/%ZOOM_00/%X/%Y.png

Ok it’s not very interesting because this map already exist in gpsVP. But you can just change the URL to access other maps. For example the Cycle map of OpenStreetMap should accessible at http://andy.sandbox.cloudmade.com/tiles/cycle/%ZOOM_00/%X/%Y.png.

Other uses

This can be also used to access some WMS maps, see examples in MapExamples.

File based map

Configuration file

A file based map must be cut in tiles to be used with gpsVP. Assuming that you already have such tiles:

• Each map has its own subfolder that you will copy in the cache folder of gpsVP.
• The configuration file should be placed in this subfolder and must be called mapcfg.ini.
• The file syntax is the same as for a web based map. Of course you don’t need to specify an URL.
• I recommend creating 2 levels of folders to store the tiles. The first level should correspond to each zoom level. The second level to each X (or Y) value. Of course you could put all the tiles directly in the cache subfolder or use only a single sublevel but it could be quite slow: storage cards can become really slow if some folders have too many files.

Where to get tiles for a file based map?

A few possibilities:

• Download them using the PC version of gpsVP.
• Download them with Googleak.
• Split a geotiff map using gdal_translate (Not easy because you probably don’t want to enter the coordinates of each tile manually. But for the one who knows how to write a script: it works, I have already done it).
• Split a map using GDAL2Tiles from the lastest version 1.6 of GDAL.
• Split a map using Maptiler (which should be released “soon”).

See also UsingScannedMaps.

Syntax of a configuration file

It’s an ini file with at least a section called [Tiled MAP].

Section [Tiled MAP]

Following entries are available:

Variables

Following variables are available for the entries Filename, URL and Subpath:

Details for %ZOOM_00:

• Zoom level as in the version 2 of the Google Map API.
• ZOOM_00 = 0 => whole Earth in one tile, 1 => in 4 tiles …
• Coarsest ZOOM_00 in gpsVP 0.4.14 = 1 (whole Earth in 4 tiles)
• Finest ZOOM_00 in gpsVP 0.4.14 = 17 (whole Earth in 2¹⁷x2¹⁷ tiles)

Details for %ZOOM_01:

• ZOOM_00 plus 1
• ZOOM_01 = 1 => whole Earth in one tile, 2 => in 4 tiles …
• Corresponds to the "level=" in the cache subdirectories of gpsVP 0.4.14
• Coarsest ZOOM_01 in gpsVP 0.4.14 = 2 (whole Earth in 4 tiles)
• Finest ZOOM_01 in gpsVP 0.4.14 = 18

Details for %ZOOM_17:

• Zoom level as in the version 1 of the Google Map API.
• ZOOM_17 = 17 => whole Earth in one tile, 16 => in 4 tiles …
• Corresponds to "data.level" in the code source of gpsvp
• Coarsest ZOOM_17 in gpsVP 0.4.14 = 16 (whole Earth in 4 tiles)
• Finest ZOOM_17 in gpsVP 0.4.14 = 0

Referenced sections

The entries ZoomOne1 to ZoomOne18 in [Tiled MAP] allow the definition of composite maps. For each value there should a corresponding "referenced" section in the ini file. The same value can be used for several zoom levels.

The referenced sections must have exactly the same name as in the entry (Example: [RefMap1]) and can use the following entries: Filename, URL, Subpath.

"ZoomOne" in the entry name has the same zoom definition as the variable %ZOOM_01, i.e. ZoomOne1 corresponds to the Earth in 1 tile.

Character encoding

You can use ANSI or UTF-8.

• ANSI is the default characters set under Windows.
• UTF-8 permits to use Unicode characters.

The Windows XP version of Notepad can save file using ANSI or UTF-8. For UTF-8 files it will automatically add a mark called BOM at the beginning of the file. If you use another text editor, make sure that it add a BOM at the beginning of the file if you want to use UTF-8.

NB: You can use Unicode characters for file or folder names but it probably won't work for the URLs.

More examples

See MapExamples.