The VMRC Map app is available for download from the Apple App Store and Google Play Store using the links below. The app uses your phone's gps to locate your position relative to the displayed map.
Click on the blue icons to view reef information.
The "Add Ruler" button will add an orange marker to the center of the map. Click and drag this marker to create the second marker. Then drag these markers to any location on the map to measure distances. Distances less than one mile will be measured in feet.