Location 1 Capture
Lat/Lon Mark
Radius km Draw
Location 2 Capture
Lat/Lon Mark
Radius km Draw

Calculate Distance between L1 and L2   km Miles    

Draw great circle route from L1 to L2

Background Map
Water Color: Land Color:
Clear / Reset 
Shift Longitude
Export Image to New Window (Disable pop-up blocker first.)

Instructions / Information:

Lat/Lon can be manually entered, or captured from an OGF URL. Capture MUST be clicked to update Lat/Lon.

The locations can be marked with a box or a dot by clicking Mark. The size of the mark can be adjusted with the drop-down.

Adding a radius value (km only), will allow you to mark the area within the radius with vertical lines (Lines), or with a solid color (Solid). Leaving Circle as the option will draw a circle around the area. Changing the Opacity will partially overlay the color over the existing information when selecting Solid or Lines.

Calculate Distance will calculate the distance between the two locations, in kilometers. Distance in miles is also shown.

Draw Great Circle Route will draw the shortest route between the two locations.

Reset Map will blank the map. The entire map can be reset, just the land, or just the water. Adding a value for Shift Longitude will shift the map east or west when Reset Map is clicked. The entire map should be reset after shifting longitude. Colors can be adjusted.

Export Image to New Window will open a saveable/downloadable copy of the image in a new winow. Slightly easier than screen grabbing.


Any opacity setting less than 100 is VERY slow. The greater the radus, the slower it goes. Try it with a small radius first!

Every update to the map is drawn over what is on the screen. There is no undo.

Colors can be changed by manually by entering the hex value, or by using the color selectors.

Additional locations can be marked by changing the Lat/Lon values, and Marking the new ones.

Blank items are assumed to be value 0.