McIDAS-X User's Guide
Version 2021.1

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GEO

Finds and displays a geostationary satellite image over a point or region.


Format

GEO map channel [keywords]
GEO station channel [keywords]
GEO lat lon channel [keywords]
GEO `city,st,co' channel [keywords]


Parameters

map

map name that defines the geographic region for which to display the image; see the MAP command for a list of valid map names, e.g., FL, MID, USA, EUR (default=value specified for the LOCATION keyword in the GEO.USER /.SITE /.CORE text file; the value is set to USA in GEO.CORE)

station

3- to 5-character station ID or 5-digit ID number at which to center the image

lat

latitude at which to center the image

lon

longitude at which to center the image

`city,st,co'

city or town at which to center the image, where city is the city or town name, st is the two-letter state or province code for the specified city and co is the two-letter country code for the specified city; if city is a U.S. city or town and appears more than once in the state, you can identify the one you want by following the city/town with the county name in brackets, e.g., 'GERMANTOWN[RICHLAND],WI'

channel

satellite channel to display; valid options are VIS, SW, WV, IR or SST, where:
VIS = visible cloud and surface features (~ 0.6μm),
SW = shortwave infrared low cloud/fog, fire (~ 3.9 μm),
WV = infrared mid level water vapor (~ 7.0 μm),
IR = infrared surface/cloud top temperature (~11.0 μm),
SST = infrared surface/cloud temperature, low level water vapor (~12.0 μm)
(default=VIS if the image time is between one hour after sunrise and one hour before sunset; otherwise default=IR)


Keywords

DAY=

day in which to begin search for image to display (default=current)

GRAphic=

graphics frame number to display the map (default=current)

IMAge=

image frame number to display the image (default=current)

MCOlor=

pol cnty

graphics color levels for map's political boundaries and county boundaries (in U.S.); use positive numbers for solid lines, negative numbers for dashed lines, and 0 to suppress drawing (default=value specified for the MCOLOR keyword in the GEO.USER /.SITE /.CORE text file; the value is set to 7 8 in GEO.CORE)

OFF=

op1..opN

set specified options to OFF; see the ON keyword for the list of options and their defaults

ON=

op1..opN

set specified options to ON; the default for all options is the value specified for the corresponding keyword in the GEO.USER /.SITE /.CORE text file; the options for the OFF= and ON= keywords and their default setting in GEO.CORE are:

 

 

DEBUG

list output from generated commands in text frame (default=OFF)

 

 

ECHO

list generated commands in text frame (default=ON)

 

 

FILTER

apply filter or stretch to image (default=OFF)

 

 

MAPS

display map over image (default=ON)

RES=

resolution, in kilometers, at which to display image (default=resolution of the primary dataset if the station, lat lon, or 'city,st,co' command format is used; default=calculated to match the geographic region if the map command format is used)

TIMe=

time in which to begin search for image to display (default=current)


Remarks

The GEO command uses the GEO.*, MAP.* and GEODATA.* context files (where * = .CORE, .SITE and .USER) to determine which data to use and how to display the data. Default parameter and keyword values are defined in the GEO.* files. Regional map definitions are defined in the MAP.* files. Satellite coverage, instrument channel and resolution information and bordering image datasets are defined in the GEODATA.* files. The datasets in GEODATA.CORE may not be appropriate for users who do not access their satellite data through the SSEC Data Center. Those users may need to create a GEODATA.USER or .SITE file in order to use GEO.

The .CORE files are supplied with McIDAS-X and should not be modified. You can, however, change their settings to your preferences. To do so, copy the .CORE file from ~mcidas/data to your $HOME/mcidas/data or another MCPATH directory, change its extension from .CORE to .USER or .SITE, then edit the settings as needed. The .USER file overrides the .SITE file, which overrides the .CORE file. This order of precedence ensures that your local settings (in the .USER and/or .SITE file) override the settings in the .CORE file.

GEO cannot produce a world composite image because the process that merges data from multiple datasets (to create a remapped composite image) is limited to one bordering dataset to the north, south, east and west of the dataset containing the image center point.

All images are remapped based on a derived projection and resolution. The projection is determined by the center point latitude of the image region requested by the command. For center point latitudes -30° to 30°, the projection is Mercator (MERC). For center point latitudes -50° to -30° and 30° to 50°, the projection is Lambert Conformal (LAMB). For all other center point latitudes, the projection is Polar Sterographic (PS).


Examples

GEO

This entry finds the geostationary satellite whose coverage includes the point or region specified for the LOCATION keyword in the GEO.USER /.SITE /.CORE file. It then displays the satellite's most recent image at the base resolution of the channel if a point was specified, or at the resolution needed to cover the domain if a region was specified. For most users, the region will be the United States because the LOCATION keyword is set to USA in GEO.CORE. For this and all examples below, unless the channel parameter is specified, GEO displays the visible channel during daylight hours and displays the infrared channel during nighttime hours.

GEO FL

This entry finds the geostationary satellite whose coverage includes the region defined by the map named FL in the MAP.USER /.SITE /.CORE file. It then displays the satellite's most recent image at the resolution needed to exactly cover the region. For most users, the region will be the state of Florida because that's how FL is defined in the MAP.CORE file.

GEO EUR WV

This entry finds the geostationary satellite that covers the region defined by the map named EUR in the MAP.USER /.SITE /.CORE file. It then displays the satellite's most recent water vapor image at the resolution needed to exactly cover the region. For most users, the region will be Europe because that's how EUR is defined in the MAP.CORE file.

GEO YSSY ON=FILTER

This entry finds the geostationary satellite that covers the Sydney, Australia region. It then displays the satellite's most recent image centered on Sydney. A filter is applied to provide optimum contrast in the displayed image.

GEO 27 -122

This entry finds the geostationary satellite that covers the region including 27° North, 122° East. It then displays the satellite's most recent image centered on that point.

GEO `NEW YORK,NY'

This entry finds the most recent GOES-East image, then displays it centered on New York, New York.

GEO `MADRID,,ES' IR RES=3

This entry finds the most recent Meteosat infrared image, then displays it at 3 km resolution, centered on Madrid, Spain. Note that two commas appear between the city (Madrid) and country code (ES) because if only one comma is specified, it's assumed to be a state or province code.


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