This button is analogous to the Control Center button found in Global Mapper desktop. Tap to display a dialog listing the various data layers currently loaded. Drag your finger to scroll the layers if needed.
Tap a layer name to toggle hiding or showing the layer. Hidden layers are indicated with a lighter color text and icon.
Tap thebutton after a layer name to bring up the Layer Options . You may hide layers, change the ordering of the layers, edit the layer name, and display the layer metadata.
Tap the home button in the top right of the Control Center to zoom to the full data extent.
You may move the dialog by touching the title bar and dragging. Tap the Close button at the bottom of the dialog, or tap the Overlay Control Center button again to close the dialog.