This function requires a TeraScan Oceansat license.
ocmin [ parameter=value ... ] [ inputfile outputfile ] ocmin [ parameter=value ... ] [ inputfile ... directory ]
Parameters are: on_pass_disk, pass_number, num_lines, calibrate, byte_output, start_sample, num_samples, pass_date, start_time, channels
ocmin creates optionally calibrated OCM (Ocean Color Monitor) TDF datasets from Oceansat-1 raw data. Input telemetry data can be read from the pass disk or standard UNIX disk files. Output is either to a user-supplied directory or a user-supplied list of dataset names. The user can specify one or more of the eight OCM channels to extract from the telemetry data. The data can also be spatially subsampled.
Answer yes if the input is from the pass disk, or no if the input is from a standard UNIX disk file.
Valid responses are [yes or no]. The default is yes.
This specifies the number of the pass to process when input is from the pass disk. Passes are
numbered starting with 1.
Valid responses are [1 to maximum number of passes that can be stored on your pass disk]. The default response is the number of the last acquired pass.
This is the number of OCM lines to extract from the oceansat-1 pass. The default is 18000.
If yes, performs radiometric calibration on the data using the correct min and max for each channel of output data. If no, data is not calibrated. (Radiometric calibration can be done on an output uncalibrated dataset with the TeraScan function ocmcal.)
Valid responses are [yes or no]. The default is yes.
If calibrate=yes, specifies whether the output is to be saved as 8-bit or 16-bit integer data. In the former case, radiance is converted to 8-bit values by multiplying by 2 and rounding to the nearest integer. In the latter case, radiance is converted to 16-bit values by multiplying by 100 and rounding to the nearest integer.
Valid responses are [yes or no]. The default is no.
This is the first sample to extract from the pass. Samples are numbered starting with 1. The swath of the OCM data is 6020 samples. However, of that, only samples 1144 to 4873 contain active data. The remaining samples are dark pixels. Calibration exists in the data stream only for samples 1144 to 4873.
The default is 1144.
This parameter controls the number of samples written to the output dataset.
The default is 3730. If start_sample=1144, this processes all the samples that contain active data in the OCM data stream.
If on_pass_disk=no, this is the date [YYYY/MM/DD] that the pass was collected. (The pass date is not stored in the telemetry.)
The default is today's date.
If on_pass_disk=no, this is the start time for data extraction. The first line with a time greater than start_time is the first output line. User is expected to input the exact pass start_time. (The start time is not stored in the telemetry.)
Any valid time is allowed (see formats). The default is 00:00:00.
This is a list of the OCM channels to extract from the oceansat-1 pass. The eight correspond to 412, 443, 490, 510, 555, 670, 765 and 865 nm.
Valid responses are [1,2,3,4,5,6,7,8]. The default is 1,2,3,4,5,6,7,8.
[1] Create a calibrated TeraScan dataset named o1.00298.1850.tdf from an OCM pass on the passdisk.
% ocmin output file : char(255) ? o1.00298.1850.tdf on_pass_disk : char( 3) ? [yes] pass_number : init ? [15] 11 num_lines : int ? [18000] 10000 calibrate : char( 3) ? [yes] byte_output : char( 3) ? [no] start_sample : int ? [1144] num_samples : int ? [3730] channels : int ( 5) ? [1 2 3 4 5 6 7 8] OCM B1 Exposure Level for I = 16 Q = 16 OCM B2 Exposure Level for I = 16 Q = 16 OCM B3 Exposure Level for I = 16 Q = 16 OCM B4 Exposure Level for I = 16 Q = 16 OCM B5 Exposure Level for I = 16 Q = 16 OCM B6 Exposure Level for I = 16 Q = 16 OCM B7 Exposure Level for I = 16 Q = 16 OCM B8 Exposure Level for I = 16 Q = 16 Line 0 Line 100 Line 200 ...etc
[2] Create an uncalibrated TeraScan dataset named o1.00298.1850.tdf from a framed OCM pass.
% ocmin o1.00298.1850 o1.00298.1850.tdf pass_date : char( 15) ? [2000/11/02] 2000/10/24 start_time : int ? [00:00:00] 18:52:00 num_lines : int ? [18000] 10000 calibrate : char( 3) ? [yes] n start_sample : int ? [1144] num_samples : int ? [3730] channels : int ( 5) ? [1 2 3 4 5 6 7 8] OCM B1 Exposure Level for I = 16 Q = 16 ...etc
Reminder: If you specify a new start_time, a time of 18:52:00 is hh:mm:ss; a time of 18:52 is mm:ss and will cause an error in earth-location.
$SATDATA/oceansat-1/ocm, orbdata, devtable, $SATDATA/oceansat-1/ocm_calib.dat
ocmcal, ocm_color, ocm_chlor, ocm_tsm, OCM overview
Data ingest is performed according to ISRO specifications as outlined in the document: Document on OCM, MSMR, & OCM Data averaging format of IRS-P4 Rev.I Oct. 1998. Doc. # ISRO-IRS-P4-PR-0071. Data Handling Division, Digital System Group, ISRO Satellite Centre, Bangalore, INDIA.
Last Update: $Date: 2003/03/28 00:38:38 $