For a while, there were two programs you could use to calibrate and convert raster map images into Magellan-Triton-GPS-compatible maps, TritonRMP Maker and RMP Creator (website in German). The author of RMP Creator apparently decided to remove the custom map calibration and conversion functions in favor of those in TritonRMP Maker, but did keep the program active for one very cool function: converting rasterized Open Source Mapping (OSM) data into Triton-compatible map formats.
It’s a Java WebStart program; here’s a direct link to the program launcher. Run the program, and zoom in to your desired geographic area:
Based on the map zoom level, the program will automatically choose which output zoom levels will be available, and you can select/deselect them by checking the boxes at the bottom. You have the choice of basic OSM street maps as above, or the OSM Cycle Map which includes topographic contours:
Specify the output filename in the ResultFiles box, click on the “Execute Conversion” button, then wait a while as the program downloads map tiles for multiple zoom levels, combines them, and converts them to a single RMP file for use in the Triton GPS unit. Once completed, you can install the map file into your Triton with Vantage Point, or copy it directly to the Map_data folder on the SD card used with the Triton. They’re not vector-map sharp, but do show streets and street names clearly enough: