APRS FLOOD GAGE SPEC 29 June 2006 ----------------------------------------------------------------------- This spec is to encourage the inclusion of water level gage information in a convenient standard format. For this purpose there are two symbols, one for H2O "/w" and the other for FLOOD "\w". The device can choose to send either of these symbols depending on its own threshold for "flooding". Or instead, if additional weather data is avaiable it can simply add the water level information to a weather report. The height above or below flood or tide level in inches is included in the position comment string as Fxxxx and that string is chosen to be compatible with the standard APRS weather reporting parameters. In addition, a voltage field Vvvv is also added. Thus, the usual APRS weather report string similar to: DIR/SPD/Gggg/Tttt/Rrrr/Pppp etc is extended by adding these additional parameters for Fxxxx water level above or below flood stage or mean tide in tenths of a foot. Values can range between +999 and -999 in tenths meaning -99.9 to +99.9 feet. Meters are not used for the on air format because it gives too little or too much resolution to fit in the fixed length 4 bytes that are required. Vxxx battery volts in tenths 128 would mean 12.8 volts Zxx Device type These fields can either be added to a WX station report where the WX symbol would continue to be used, or the available weather data can be added to a Water Gage report using either of the two water symbols. The standard WX report allows for any field to be indicated as not available either by omission or by replacing the value with "...". SInce the wind direction and speed and temperature are required fields, this means the minimum weather report with flood info is WX symbol -plus- .../...t...VxxxFxxxx or the minimum water gauge is Water symbol -plus- VxxxFxxxx/ZFA Notice that if water data is added to a WX report, then only Fxxxx and optional Vxxx are added to the WX report. But if WX data is added to a water gage report, then the minimum fields of .../...t...Fxxxx are required. Examples are: Weather reports: DDMM.hhN/DDDMM.hhW_ddd/sss/Gggg/Tttt/Fxxxx... DDMM.hhN/DDDMM.hhW_ddd/sss/Gggg/Tttt/Fxxxx/Vvvv... DDMM.hhN/DDDMM.hhW_ddd/sss/Gggg/Tttt/Rrrr/PppppFxxxx... Water Gage reports: DDMM.hhN/DDDMM.hhWwFxxxx/ZFA DDMM.hhN/DDDMM.hhWwFxxxxVvvv/ZFA DDMM.hhN\DDDMM.hhWwFxxxxVvvv/ZFA DDMM.hhN/DDDMM.hhWwddd/sss/Gggg/Tttt/Fxxxx/ZFA DDMM.hhN/DDDMM.hhWwddd/sss/Gggg/Tttt/FxxxxVvvv/ZFA DDMM.hhN\DDDMM.hhWwddd/sss/Gggg/Tttt/FxxxxVvvv/ZFA Notice that two of these indicate the FLOOD symbol (\). Also notice that existing software needs to now consider parsing the appearance of any WATER or FLOOD symbols to see if they also include Weather. Also, everyone's weather parser needs to look at the WX fields for the optional additional Fxxxx or Vvvv fields. de WB4APR, Bob