XPost: alt.windows7.general, alt.comp.os.windows-10   
   From: G6JPG@255soft.uk   
      
   On 2026/1/19 20:11:34, R.Wieser wrote:   
   > As I cannot get any formule to work I'm going to try this one last time.   
      
   []   
   There are three stages to this - I would say best sorted individually   
   before trying to combine them. (Stages 2 and 3 are related and might   
   need reversing in order.)   
      
   1. The mathematical conversion from latitude (and longitude) to the   
   position on the plane map *relative to its centre*, assuming that's   
   where the Greenwich meridian crosses the equator. This is the one that   
   might or might not be just a tangent function (for latitude; for   
   longitude, it's just scaling and offset, see below).   
      
   2. The _scaling_ required, depending on the size of the map image. Which   
   again will depend on the size of the image (and may be different for X   
   and Y).   
      
   3. The _offsetting_ required to account for the fact that the above   
   point is not at 0, 0 on the image (probably offset by half the size of   
   the map being used, in pixels, in each direction).   
      
   I think _most_ of those contributing to this discussion know that, but   
   have not been making it very clear which bits of their formula(e) do what.   
   --   
   J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf   
      
   The fact that there is a highway to hell and only a stairway to heaven   
   says a lot about anticipated traffic numbers.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)