People often include zoomed in maps of the same area. Sometimes a marked spot when zoomed in more turns out to be 2-3 places close together. This is only for places to metal detect.
Red was for a general type of search, not gold or silver specific but could include those targets.
Here is from my file of definitions for marked spots.
Red circle is to mark areas, of loose or surface coins/treasure and artifacts of value, down to 1-2 feet deep.
Red line box (or solid filled circles) for very deep coins/treasure or artifacts of value.
Orange line box (or solid filled circles) for deeper man made gold objects or pocket gold in veins.
Orange outline circles, for man made gold objects from surface down to 1-2 feet or shallow rich native gold.
Blue line box (or solid filled circles) for deeper silver targets.
Blue circle is to mark areas of loose or surface silver coins/treasure, down to 1-2 feet deep.
Green in general is a color indicator, I use for various other targets mostly archaeological (old ruins or foundations but especially those non-metallic objects such as Indian flints, glass, pottery, carved stone with treasure signs).