Easy Lat/Long Map Borders
by, 01-23-2012 at 07:36 PM (1712 Views)
Ever try to make a border for a map with edges that are parallels and meridians; like the Lambert Azimuthal or the UTM Projections shown below? I found a vector file with the entire globe as grid lines in 1,5,10, 15 and 30 degree increments. With the new GM 13 "split lines at intersections feature" and the attached vector file, it's fairly easy.
Just open the grid vector file in a second instance of GM, select the Lat/Long lines that border your map, and move them to a separate layer. Turn off the rest of the layers. Select all 4 of the Lat/Long lines bounding your map, then use "Split lines at intersections". Next, delete all segments except those that border your map, and while they're still selected, "combine" the lines into one border "frame". Then just copy it to the clipboard and paste it into your map project. From there you can choose pixel width, color, style, etc.
I use these two maps as backgrounds with a script for importing the latest GOES West weather satellite images. With the red dot exactly at my desk (using GPS coordinates) and the 100 mile range rings, it's easy to tell where things are in relation to my location. I also do this (custom background, my location, range rings, and a script) to get my latest local NEXRAD weather radar image at various scales. I'll post about that later.
(TIPS: Obviously, this only works for whole degrees. If you have trouble near the IDL or the Poles, try reversing the vertex order of the troublesome line(s). Open and use the grid in it's native Geographic Projection, GM will re-project when you paste to your map. You can also use the Lat/Long "frame" with "Create area from selected line" to generate an area feature polygon for cropping.)
If you have questions or need help, let me know.
Ice Age Mark