Background on Updating APRS SYMBOLS 17 April 2008 ---------------------------------------------------------------------- The following information was summarized from Stephen Smith's WA8LMF's email and does a good job of explaining what it takes to upgrade APRS symbols in many client programs: As Stephen has pointed out many times before, the actual symbol graphic IS NOT TRANSMITTED. Only a two character alpha-numeric code is sent over the air. This code causes the appropriate symbol to be selected by the client station software from a set of graphics already stored on the recipient's machine. To update symbols, everyone must change/update the stored symbol set in their program(s) before a newly-defined symbol will become useful. As an example, Stephen tranmsmits the SSTV symbol from his car when he is doing mobile SSTV "livecam", but this causes a thundercloud to show on findu. [ This is the result of a symbol standards change OVER A DECADE AGO! ] * Only UIview, APRSplus, XASTIR and AGWtracker can easily update their symbols by upgrading external files. * Win/MacAPRS have the symbols embededed in the compiled .EXE file so they cannot have new symbols without new codes and distributions. * APRSpoint doesn't even use the standard APRS symbol set. It only uses the standard Microsoft MapPoint "pushpin" symbols. OVERLAY SYMBOLS which were introduced in 1995 are even more of a problem! The only Windows application that even renders overlay characters is UI-View. * WinAPRS DOES NOT render overlays. * APRSpoint DOES NOT render overlays. * APRSplus DOES NOT render overlays. * The UIview plug-in for MapPoint DOES NOT render overlays. * APRS-CE (for Pocket PC) DOES NOT render overlays. * Pocket APRS (for Palm devices) DOES NOT render overlays. Further, even the base symbol sets in WinAPRS, Pocket APRS and APRS/Ce are years out of date. They cannot be updated (they are buried in the compiled .EXE file of these programs and inaccessible). To get UIview to render the new overlays in it's internally-displayed maps (i.e. not in external display plugins like UI-Point, UI-Route, etc), will require revision of the _symbols.ini _file that is part of UI-View's symbol display mechanism. This is an excerpt from symbols.ini for illustration. REM Primary Table Alternate Table REM Symbol GPSxyz Index Description GPSxyz Index Description REM ------ ------ ----- ----------- ------ ----- ----------- !, BB, 0, Police Stn, OB, 0, Emergency ", BC, 1, No Symbol, OC, 1, No Symbol #, BD, 2, Digi, OD, 2, No. Digi $, BE, 3, Phone, OE, 3, Bank %, BF, 4, DX Cluster, OF, 4, No Symbol &, BG, 5, HF Gateway, OG, 5, No. Diam'd Stephen SMith updates this file when new symbols are defined. The overlayable symbols requires placing "No. " in front of the symbol label as in "Digi" and "HF Gateway" above. Note that "No" without the period, as in "No Symbol", denotes an unassigned slot. "No." WITH the period and following space denotes an active symbol slot that is overlayable. Further, note that the entire Description field is limited to about 10 characters due to a un-changeable parser inside UIview. Placing the "No. " prefix on a symbol description, limits the label that shows in the selection dialog to only 6 characters. Finally, Bear in mind that any symbol must fit in a 16x16 pixel grid and not be rendered illegible by overlay symbols.