Hi Marco,
I've included information on the Custom Map URL feature (along with an example URL from USGS) and information on how to add Thunderforst Maps to MotionX-GPS below. This will be the only way to download and store Thunderforest maps (the provider of MotionX maps).
Custom Map URLs:
The Custom Map URL format is specific to the map provider and it varies from map provider to map provider. It consists of a text string beginning with "http://" or "https://", has a domain name, some possible parameters, and there will be some symbols that MotionX-GPS substitutes with real-time tile request information when it contacts the server. You will need this feature unlocked at Menu > Setup > Purchases and you can enter URLs at Menu > Setup > Custom Map Types > New. If you'd like to make the map downloadable, toggle "Download map for offline use" after entering the URL.
The possible symbols that MotionX-GPS accepts in the URL are [X], [Y] and [Z] coordinates and zoom or [T] or [Q] for the quadrant.
To lookup map imagery in a map provider’s database, most will use tile coordinates of x and y, plus zoom, however, some map providers use a single quadrant coordinate instead. While some map servers expect zoom/y/x in the URL for the tile request, other map providers use different formats, and unfortunately, there is no specific standard ordering. For instance, you may receive the following URL to use for the map server:
https://tile.examplemap.org/terrain/3/2/1.pngIn order for MotionX-GPS to properly fetch tiles from a map provider, a generalized prototype URL scheme must be furnished. This generalized URL scheme will be used by MotionX-GPS to fetch any tile, at any coordinate, with any zoom. To accomplish this, the symbols "[X]", "[Y]", and "[Z]" (without the quotes) is inserted in the place of explicit coordinates.
With the example URL given above, a custom map types can be created to be used in MotionX-GPS by mixing the known explicit URL with the symbols representing x, y, and zoom to form a custom map prototype URL:
https://tile.examplemap.org/terrain/[Z]/[X]/[Y].png
When MotionX-GPS needs a map tile fetched from a provider, it will replace the "[X]", "[Y]", and "[Z]" symbols with the actual coordinates and zoom for the tile required, and then use the resulting URL to contact the map provider's server to fetch the map tile.
Note that some map providers dispense of the coordinate/zoom scheme altogether and use a single quadrant parameter instead. This quadrant may be specified in the prototype URL using the "[T]" symbol or "[Q]" symbol (no quotes).
You can perform a search online for "map servers URLs" to find map tile servers of your own to use. Here’s an example of USGS’s topographic map server URL formatted correctly for MotionX-GPS.
USGS Provided Topo Map URL:
https://basemap.nationalmap.gov/arcgis/ ... /MapServerUSGS Topo Map URL Formatted for MotionX-GPS (Copy & Paste into MotionX-GPS):
https://basemap.nationalmap.gov/arcgis/ ... rver/tile/[Z]/[Y]/[X]
Select here for all USGS URLs
Note: The X, Y, Z, Q, and T values in URLs are generalized parameters, and are included in these URLs intentionally. Do not replace them with actual numeric coordinates, except for testing in an external web browser.
Adding Thunderforst Maps:
Go to Thunderforest's website to sign up for an account, enter your details, and then select "Create Account."
Next, go to your email, find the message sent to you by Thunderforest, and then select "confirm my account".
You should be redirected to sign-in to your Thunderforest account. Once you're signed in, scroll down to the "Tile Layers URLs" section in the dashboard, and then copy the URL for the map type you'd like to use.
Open MotionX-GPS and go to Menu > Setup > Custom Map Types > New, and paste the URL.
Modify the URL to change curly braces into square brackets, i.e. for the Outdoors map, you would modify as follows:
BEFORE:
https://tile.thunderforest.com/outdoors/{z}/{x}/{y}.png?apikey=your-unique-api-key
AFTER:
https://tile.thunderforest.com/outdoors/[z]/[x]/[y].png?apikey=your-unique-api-key
All the best,
Tom Lewin