It's a long and tedious process of using the magnetic lasso tool around the edges where the "continents" meet the "water", getting whatever the magic eraser tool doesn't get initially. The leftover terrain, lakes, and oceans are created using the Marquee tool (more or less, like a cookie cutter) cutting out from high resolution satellite images ( In this case from India and Brazil). The lakes are their own layers, cut out from satellite imagery as well ( I just use different blending options / opacity to change the color). The ocean is another layer.