--- Richard Polivka <[EMAIL PROTECTED]> wrote: > I agree on the -99999 selection since any other real > value is possibly correct. > > Gerry Creager <[EMAIL PROTECTED]> wrote: > too! And you just raised a key one. We should have > a standard value for > *Missing Data* such as, -99999 (which is, in fact, > one such well > recognized value in the meteorological community).
I see one sticky wicket for that in the consumer equipment (now that I got to see the data format). Some of the units send unsigned integers for certain values in their serial data stream. They're also using fixed width fields in the data stream. For example, if the wind vane broke or didn't exist, what value do you send for wind direction? The Ultimeter uses 0-F to send 16 directions of wind. The wind speed is encoded in two hex digits (no mention of signed or unsigned here, though) so what do you send there? A report of 00 is valid as is 8A (140MPH not often, but it might be valid in a hurricane). If it's perhaps a simple firmware change that can be installed in all existing units, maybe the no sensor value should be an overrange. Wind speed sensor missing would be FF (unless there are 255 MPH winds somewhere). It looks like the temperature sensors might be get away with a negative underrange, though, since they have to transmit negative temperatures. I can't tell how they do it, though (whether signed integers or some offset). ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ _______________________________________________ Xastir mailing list Xastir@xastir.org http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir