i am working on a group project at university. we should read a map (.png file) and try to find the seas on the map. i know how i can read from a png file to an array. but i cannot find how i find the blue colors (or the colors that show seas). i googled it but i dont find anything about it (everything is about filtering, rescaling etc...) in fact i dont know how i can find it and the main sentences that i can google.
What can i do? Any hints? i will be very glad for all supports.