AREA is the data area. Only data within the area specified will be
Areas may be defined containing subareas. Subareas must be separated
by slashes. Each subarea is additive, +, or subtractive, -, depending
on the first character following the slash, with + being the default.
Additive subareas add stations to the list of valid stations;
subtractive subareas eliminate stations which were previously valid.
Subareas may be specified in the following ways:
This defines a latitude/longitude range where (lat1, lon1) is the
lower left corner and (lat2, lon2) is the upper right corner.
West longitude is negative.
This defines a latitude/longitude range by the center latitude and
longitude. The lower left corner is (clat-dlat; clon-dlon); the
upper right corner is (clat+dlat; clon+dlon). No corrections are
made for the poles or the International Date Line.
This is an abbreviation for a geographic area defined in the
GEMPAK geographic table which includes abbreviations for states,
provinces, and countries, as well as other names. A suffixed + or *
will decrease the extent of the geographic area. A suffixed - will
increase the extent of the geographic area.
This defines an area centered on a station found in the GEMPAK
station table. A suffixed + or * will decrease the extent
of the geographic area. A suffixed - will increase the extent
of the geographic area.
This includes all the stations in the current data set.
This area includes those stations located in the state, province
or country defined by ST. Only some countries are recognized
(US,CN,MX,CI,BW,AU); other countries may be specified using method 6.
This area includes those stations located in the country defined
This area includes the stations listed, where STNi may be a station
identifier or a station number.
This area defines a range of integer values for the station header,
SHDR. Valid keywords for SHDR are:
COUN -- country
SELV -- elevation (in meters)
SLAT -- latitude (in degrees x 100)
SLON -- longitude (in degrees x 100, West is negative)
SPRI -- priority
STAT -- state
STID -- character identifier
(6 digits for surface--usually the WMO
5-digit number followed by a 0)
where COUN, STAT and STID are not very useful, since the integer
representation of characters is system dependent.
For example, SELV:0:2000 specifies stations whose elevations are
less than 2000 meters.
This area corresponds to a slightly larger area than that specified
by GAREA. It will ensure that data will appear near the bounds of
the view region.