Its a cool app, I do really like it. Only real issue I have is with the economic map.
When it comes to the other regions, it provides plenty of detailed information. For the stormlands, it provides little and distorted information, lacking a number of key features.
I'm not trying to take a dig at you and your research, Jeff. Just pointing out that the source you used was imperfect. Absolutely brilliant for the other regions but shoddy when it came to the Stormlands.
Yes, the Stormlands has a reasonably low population for its size but can still gather an army of around 30000. Before the Great Spring Sickness House Dondarrion is able to muster up 4,000 men alone, despite having a modest castle in the Marches. Also, the lands on Cape Wrath are quite fertile, the issue is that peninsula is scarcely populated and densely forested.
The other issue is that the map provided on the website is that the amber locations are placed either in the red mountains or west of them. This is only partly following canon. I'd think that the ancient forests (i.e. the Rainwood) of Cape Wrath would have produced amber, rather than the mountains or grasslands of the Marches. In fact, that's what the World of Ice and Fire says.
"As the marches are famed for their strong castles and their ballads, the Rainwood is known for its rain, its silences, and a wealth in fur and wood and amber."
Another point is that your project is near one of the major (and few) river trade routes of the Stormlands. The Slayne River, which flows south into the Sea of Dorne.
Evidently, this area is not up to date with the canon for the river but regardless, think about maybe adding a mountain pass to link it to that route. Amber mining does not require digging into rock most of the time. Because amber is fossilized tree resin, it will most often be found in soil or sand. This is the same for the amber found in the mountains of Burma. Its dug/dredged up out of the valley's soil, rather than mined in a usual sense.
Here are some images of amber 'mining' in Burma and its impacts, along with its impact in Ukraine.