A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ed Popko
Date: 2016 Mar 6, 04:52 -0800
As you noted, this PostScript program can only center the plotting sheet on whole degrees of latitude or longitude. To center the plotting sheet on any degree/minute latitude or longitude would be quite useful but to do so would entail a substantial rewrite. Perhaps I should have though about this when Jim Morrision and I were playing with this.
I do have another version of this program that adds one small feature - a way to precisely locate a graphic (a dot perhaps) and a label to the chart. That position can be whole or fractional degrees. Since I take sights from my back yard with the aid of an artificial horizon thus I have located it's known position (KP) which is 42deg 1.281667 min latitude and 74 deg 6.637167 min longitude. In the example plot below, the MAV dot marks the KP. If this small addition is useful, I'll send the PostScript program. If you look this point up in Google Earth, you will see that Woodstock, New York isn't exactly a deep water port (ha ha).
On the subject of diagrams, I have another simple PostScript program that creates meridian diagrams. You are welcome to have it as well. In round numbers, I'm near 75 deg West. The rim scales show longitude, Greenwich reference and local hour angle. No great shakes, but convenient if you are graphically playing with time conversions etc.
I will give some thought to the small area polt sheet code rewrite but it's not something I can tend to immediately.