How to Make URLs to Open Gaia GPS at a Coordinate
You can create a URL that opens Gaia GPS to a given lat/lon and zoom. Here is an example you can click from your iPhone or iPad to open Gaia:
To change how to url opens, you can substitute the lat and lng values for a different location. Change the z value to edit the zoom level. The higher the number is, the closer the zoom will be. 4-15 is the typical zoom range.