I recently made a long drive across Kansas and eastern Colorado, coming back from a visit to Indiana. Kansas is a really long state (but my wife points out that it is not much wider than Colorado.) OK, so it is a long and flat state. When you drive across Kansas, you have a lot of time to think.
I also had my GPS receiver, my notebook computer and a copy of Street Atlas 2005. This got me thinking about VHF grid locators and where the various latitude and longitude lines are located. I had previously created a map of Colorado for my web page that indicates the grid locators (see http://www.k0nr.com/rwitte/vhf_grids.html). At that time, I noted that the eastern border of Colorado (adjacent to Nebraska and Kansas) does not fall exactly on the grid line, which is 102 deg W Longitude. In other words, the eastern grids DM87, DM88, DM89 and DN80 actually extend slightly into Nebraska or Kansas. I watched the GPS receiver as I approached the state line westbound on I-70 and it agreed by clicking over to DM89 while I was still in Kansas. Street Atlas shows the state line at 102 deg 2.8 min.
Since all knowledge can be found on the Internet, I started surfing around looking for confirmation and an explanation of why the state line seems to be in the wrong place. In fact, I found a number of references that simply said that the eastern boundary of Colorado is the 102 deg W longitude line. See http://www.netstate.com/states/geography/co_geography.htm (I guess I could just chalk this up to round off.) Interestingly, the same web site lists the western boundary of Kansas as 102 deg 1 min 34 sec W.
Mount Sunflower is the highest point in Kansas at 4039 feet in elevation. I have never been to Mount Sunflower, but I know it is a good VHF operating spot. I had always assumed that it was located in DM99, based on a cursory examination of the map. As I stared at Street Atlas, all of the sudden it hits me that Mt Sunflower may not actually be in DM99. Street Atlas shows it as 102 deg 2.2 min West (and 39 deg 1 min North latitude), which is clearly west of the 102 deg line. I checked the Peakbagger.com web site and it shows the longitude of Mt Sunflower as 102 deg 2 min W. This same longitude is listed on the America’s Roof web site at http://www.americasroof.com/ks.shtml
OK, so now I wish I would have stopped at Mt Sunflower, got out my GPS and verified its lat/lon. Well, maybe on the next trip. For now, I conclude that Mt Sunflower is in DM89. (Phil N0KE later confirmed that this is correct.)
I never did find a reference that explains why the state line is not exactly on 102 deg so I can only speculate on the reason. I did find that this situation is not unique to Colorado, in that state lines are often close to but not exactly on integer latitude or longitude lines. In a few places, the reason given is that survey techniques were not that accurate when these states were first defined. Given the survey tools available at the time, I think this is a reasonable explanation. More to the point, the folks that plotted out the state lines back then were amazingly accurate given what they had to work with. I suppose there is little benefit and lots of hassle in trying to correct this problem now.