On Mon, Dec 12, 2011 at 2:20 PM, Stewart C. Russell <scr...@gmail.com> wrote: > If anyone's confused about what these maps would look like, I have some > examples here: > http://glaikit.org/2011/12/11/not-really-getting-the-azimuthal-equidistant-projection-right/ > > They were made with the not-exactly free AZ_PROJ, a utility written entirely > in PostScript.
Okay, I have a pert of the answer here, the May and June 1979 issues of Byte Magazine, with a two part article on map making. So, I have the source code (written in BASIC, sigh) that will take a latitude / longitude and turn that into an X / Y point to be plotted. In other words I can now look at the math and logic of what needs be be done in the transformation... > For a great (but non-free) example of a grey line (day/night) map, see > http://pskreporter.info > > Cheers > Stewart > > On 2011-12-12, at 9:23, Colin McGregor <colin.mc...@gmail.com> wrote: > >> Last Saturday I was at a party co-hosted by Richard Weait (thanks), >> where the topic of maps for amateur radio use came up. >> >> A topic that has been of interest to me is amateur radio and disaster >> response. >> >> So, I am looking for software that will generate two maps from Open >> Street Map data: >> >> - An azimuthal equidistant projection map for any arbitrary latitude / >> longitude >> - A day and night map (ie: what parts of the world are CURRENTLY in >> sunshine / darkness) >> >> So, what makes the requirement for the above a little tough? I want >> the software to be under the GPL (or some other open license) so it >> can be redistributed without issue. I want it for Linux (so the OS to >> support the application can also be redistributed without issue). I >> want the application to run stand-alone (so if there is a problem with >> the internet connection I don't want the application to suddenly >> become useless). The data for this can not be more than a few MB at >> most (but then this shouldn't be an issue, given that road, rail, land >> use data is irrelevant for these apps, all that is needed is >> continental outlines, MAJOR lakes, rivers, islands and cities). >> >> So, why the interest in these maps? >> >> Many amateur radio antenna are directional (doing a better job of >> receiving (or transmitting) a signal in one particular direction). >> With an azimuthal equidistant projection map done for your location, >> you can draw a line from the center of the map to the location you are >> interested in and that will instantly tell you the direction to adjust >> your directional antenna. This is static map, as in you generate the >> map once for a given latitude / longitude you are effectively done. >> >> High frequency radio signals can refract off the ionosphere allowing >> very long range communications with low power transmitters. What >> frequencies refract well depends on a number factors, including >> sunshine / darkness. So knowing that the place you want to talk to is >> in darkness is useful. So, a day night map would have to be dynamic, >> being updated say once per minute ... >> >> Anyone with ideas as to where I could / should turn for the above? >> >> Thanks. >> >> Colin McGregor >> VE3ZAA >> >> _______________________________________________ >> Talk-ca mailing list >> Talk-ca@openstreetmap.org >> http://lists.openstreetmap.org/listinfo/talk-ca _______________________________________________ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca