satmaster - creates master file matching a satellite sensor

satmaster - Creates master file matching a satellite sensor

SYNOPSIS

satmaster  [ parameter=value ]  [ outputfile ]

Parameters are: satellite, sensor, geo_correct, pass_date, start_time, delta_line, num_lines, delta_sample, start_sample, num_samples

DESCRIPTION

The satmaster function creates a master file (see master) that describes the earth location of a particular satellite sensor during a given satellite pass. This can be used when importing unmapped sensor data from another source; with satmaster you can duplicate the earth location of the satellite sensor, and then use copyxfm to copy the attributes into the imported dataset.

satmaster prompts you for information about the satellite overpass from which the sensor data was collected. This includes the start date and time, the number of lines and samples, and information about any subsampling that was done to the data.

This function works for valid satellites and sensors that are described in the Terascan software. Currently, valid satellites can be specified by lookup table (in the file $SATDATA/SATSETUP), and described in satellite specific directories that contain orbital elements (see orbdata) and sensor files. Sensors are still compiled into Terascan software, and cannot currently be added. In the future it may be possible to add a sensor which can be fully parameterized by its scan angles.

PARAMETERS

satellite: The name of the satellite. Valid satellites are those listed in SATSETUP with valid orbital elements. Normally this is the NOAA TIROS and U.S. Air Force DMSP series of satellites. There is no default.

sensor: The name of the sensor. Valid sensors are those associated with the satellite in the SATSETUP file, and which have sensor description files located in $SATDATA/satellite-name. For NOAA TIROS satellites, valid sensors are [avhrr, hirs, apt_avhrr]; the default is avhrr. For DMSP satellites, valid sensors are [ols, ssmi, ssmt1, ssmt2]; the default is ols.

geo_correct: If hrpt_type=avhrr, answer yes if the projection is geometrically corrected. This means the AVHRR projection retains the same resolution all the way along the scan direction. For more information about geometric correction, see avgc.; Valid responses are [yes or no]. The default is no.

pass_date: This is the start date of the pass.; Any valid date is allowed, see formats. The default is today's date.

start_time: This is the start time of the first line of sensor data.; Any valid time is allowed (see formats). There is no default.

delta_line: This parameter specifies the rate of subsampling in the direction of subtrack. If delta_line=3 every third line will be used. If delta_line=1, all lines will be used.; Valid responses are [1 through 25]. The default is 1.

num_lines: The number of sensor lines (scans) in the master. Valid responses are any number greater than 1. There is no default.

delta_sample: This parameter specifies the rate of subsampling in the scan direction. If delta_sample=3 every third sample will be used. If delta_sample=1, all samples will be used.; Valid responses are [1 through 25]. The default is the value of delta_line.

start_sample: The leftmost sample number to subset from the full sensor swath. Samples are numbered starting with 1.; The valid range is [1 to <total sensor samples>]. The default is 1.

num_samples: The number of samples from start_sample. These two parameters control the definition of a subset of a sensor swath. If geo_correct=yes, then delta_sample * num_samples input samples will be processed to produce geometrically corrected lines which are then subsampled according to the delta_sample parameter.; The valid range is determined by [start_sample -1 + num_samples * delta_sample <= sensor samples]. The default is 1 + (<sensor samples> - start_sample)/delta_sample.

EXAMPLES

The following example creates a master which matches a NOAA HIRS scanner:

% satmaster
output file    : char(255) ? [Master]
satellite      : char( 11) ? noaa-14
sensor         : char(  9) ? [avhrr] hirs
pass_date      : char( 15) ? [95/03/08]
start_time     : char( 15) ? 14:20:00
delta_line     : int       ? [1]
num_lines      : int       ? 600
delta_sample   : int       ? [1]
start_sample   : int       ? [1]
num_samples    : int       ? [56]

FILES

orbdata