PS fill color flat map

Quick answer：

In Photoshop, 'fill color flat map' refers to the process of filling an area of a flat map with a specific color. This is often done for visual effect, to highlight certain features, or to create a uniform background. To fill a color flat map in Photoshop, you would select the area you want to fill, choose the color from the color picker, and then use the 'Fill' command or the 'Paint Bucket Tool'.