I'm using this library to finish my final project and I have to say I'm no familiar with the maps worlds. My question is if geotools has a method to show automatically the coordinates references in the map, and how use it? That would be really helpful because I spend a lot of time trying to find it without success. I use the quickstart example to show a shapefile with the worlds map. The user can select a rectangular zone of interes and then the application draw the Sea Surface Temperature. The map generated needs the references of where are positioned because we export it to a png image.
One example of what I am looking for are the blue lines in the map below.