APRS-IS Filters

Parameter	Filter Type	Description
a/latN/lonW/latS/lonE	Area	The area filter works the same as range filter but the filter is defined as a box of coordinates. The coordinates can also been seen as upper left coordinate and lower right. Lat/lon are decimal degrees. South and west are negative. Up to 9 area filters can be defined at the same time.
b/call1/call2…	Budlist	Pass all traffic from exact call: call1, call2, … (* wild card allowed)
d/digi1/digi2…	Digipeater	The digipeater filter will pass all packets that have been digipeated by a particular station(s) (the station's call is in the path). This filter allows the * wildcard.
e/call1/call1/…	Entry station	This filter passes all packets with the specified callsign-SSID(s) immediately following the q construct. This allows filtering based on receiving IGate, etc. Supports * wildcard.
f/call/dist	Friend Range	This is the same as the range filter except that the center is defined as the last known position of call. Up to 9 friend filters can be defined at the same time.
g/call1/call1/…	Group Message	This filter passes all message packets with the specified callsign-SSID(s) as the addressee of the message. Supports * wildcard.
m/dist	My Range	This is the same as the range filter except that the center is defined as the last known position of the logged in client.
o/obj1/obj2…	Object	Pass all objects with the exact name of obj1, obj2, … (* wild card allowed)(spaces not allowed) (| => / and ~ => *)
os/obj1/obj2…	Strict Object	Pass all objects with the exact name of obj1, obj2, … (* wild card allowed) (| => / and ~ => *) Objects are always 9 characters and Items are 3 to 9 characters. There can only be one os filter and that filter must be at the end of the line.
p/aa/bb/cc…	Prefix	Pass traffic with fromCall that start with aa or bb or cc…
q/con/ana	q Contruct	q = q Construct command con = list of q Construct to pass (case sensitive) ana = analysis based on q Construct. I = Pass positions from IGATES identified by qAr or qAR. For example: q/C Pass all traffic with qAC q/rR Pass all traffic with qAr or qAR q//I Pass all position packets from IGATES identified in other packets by qAr or qAR
r/lat/lon/dist	Range	Pass posits and objects within dist km from lat/lon. lat and lon are signed decimal degrees, i.e. negative for West/South and positive for East/North. Up to 9 range filters can be defined at the same time to allow better coverage. Messages addressed to stations within the range are also passed.
s/pri/alt/over	Symbol	pri = symbols in primary table (| => /) alt = symbols in alternate table (| => /) over = overlay character (case sensitive) For example: s/-> This will pass all House and Car symbols (primary table) s//# This will pass all Digi with or without overlay s//#/T This will pass all Digi with overlay of capital T
u/unproto1/unproto2/…	Unproto	This filter passes all packets with the specified destination callsign-SSID(s) (also known as the To call or unproto call). Supports * wildcard.
t/poimqstunw t/poimqstuw/call/km	Type	Pass all traffic based on packet type. One or more types can be defined at the same time, t/otq is a valid definition. p = Position packets o = Objects i = Items m = Message q = Query s = Status t = Telemetry u = User-defined n = NWS Weather & Weather Objects w = Weather Note: The weather type filter also passes positions packets for positionless weather packets. The second format allows putting a radius limit around "call" (station callsign-SSID or object name) for the requested station types.

Sample filter entries

r/27.99673/-80.659072/1	Passes all packets within 1 km of Lynn's house
b/KJ4DXK*	Passes all packets from any SSID belonging to KJ4DXK
u/APWW*/APWM*	Passes all packets sent to a TOCALL starting with APWW (APRSIS32) or APWM (APRSISCE)
-b/WINLINK	Blocks all packets from WINLINK
-s/S/S	Blocks all packets using a Space Shuttle (/S) or Satellite (\S) symbol
-s//a/DW	Blocks all packets using a red diamond (\a) overlaid with DW
s/@/@	Passes all packets using the Hurricane prediction (/@) and Hurricane (\@) symbol
-b/METAR-2	Blocks all packets originated from METAR-2
-u/APFMET	Blocks all packets with a toCall of APFMET
-e/METAR-2 or -e/METAR*	Blocks all packets entering the APRS-IS from METAR-2 or any METAR station
-o/MTR*	Blocks all objects that start with MTR. Note that -b/MTR* won't work because the water meters are objects owned by METAR2, not stations that start with MTR.
-s/w	Blocks all stations using Water Station (/w) symbol