avasin [ parameter=value ... ] [ outputfile ] avasin [ parameter=value ... ] [ directory ]
Parameters are: on_pass_disk, pass_number, tape_device, first_file, num_files, vis_delta, small_ir_delta, large_ir_delta, use_master, master_file, start_spin, num_spins, start_percent, width_percent, goes_fmt, save_common_doc.
avasin creates a TeraScan TDF dataset from raw GOES S-VAS telemetry data. The dataset contains two-dimensional image data from visible and infrared sensors and an overlay of injected grid point data.
The raw data can be read from the pass disk or from tape. Raw data on tape must be in TeraScan Archive Format (TAF).
GOES (Geostationary Operational Environmental Satellite) is a weather satellite in an earth-fixed orbit over the equator which retransmits environmental data. Its imaging sensor is called the VISSR (Visible and Infrared Spin Scan Radiometer); GOES-7 contains an enhanced sensor called the VAS (VISSR Atmospheric Sounder). The telemetry which contains VAS image and sounder data is called Stretched VAS (S-VAS), sometimes called Mode AAA. The TeraScan avasin command extracts the VISSR image data and injected grid data from S-VAS telemetry.
The overall spatial subset of data to be extracted can be specified in one of two ways:
1) the smallest rectangular area required to cover a region defined by a master dataset. 2) a rectangular area of specific size, beginning at a user-specified time and scan sample.
GOES-7 begins a north-south scan of the earth one minute past every half hour. Currently the satellite scans the full earth disk every three hours, and scans a partial disk most other times. Check a GOES-7 transmission schedule, available via FAX from NESDIS Satellite Operations (301)763-5045 / FAX:(301)763-7083.
In its normal picture-taking mode, called 3-stage MSI mode, GOES transmits one visible channel with 0.9 km resolution, one small detector thermal infrared channel with 7 km resolution, and two large detector infrared channels with 14 km resolution. The spectral bands of the latter two channels vary according to the transmission schedule. Usually one is a water-vapor absorption band.
Are the telemetry frames on disk or tape? Answer yes if the telemetry frames are on disk and no if the frames are on tape.
Valid responses are [yes or no]. The default is no.
If on_pass_disk=yes, avasin prompts for pass_number. This is the number of the pass on pass disk to process. You can list passes on disk with the command lspass.
The range of valid responses depends on the disk configuration. The default is the most recent pass.
If on_pass_disk=no, avasin prompts for tape_device. This takes the device address of the input tape device. Tape device names are machine specific.
This must be a valid UNIX tape device address.
This is the number of the pass on tape where processing is to begin. avasin only prompts for this parameter if the answer to on_pass_on_disk is no (i.e. pass is on tape).
This number is relative to the current position on the tape. For example, if the tape is positioned at the beginning of the tape, first_file=2 will process the second pass on the tape. If the tape is positioned at the third pass on the tape, first_file=1 will process the third pass, and first_file=2 will process the fourth pass.
Valid range [>=1]. The default is 1.
This is the number of consecutive passes to process when the passes are archived on tape and the output dataset is a directory.
Valid range is [>=1]. The default is 1.
This specifies the rate of visible channel subsampling. If vis_delta=4 every fourth sample of every fourth line will be used. If vis_delta=1, all samples and lines will be retained. Specifying vis_delta=0 indicates that the visible data should not be extracted/stored in the dataset. A subsampling of 4 gives the same visible resolution as full resolution infrared data. NOTICE: if ARMA GOES visible data has subsampling rate higher then the one specified by vis_delta, then vis_delta value will be corrected. Example: specifying vis_delta=2 for VIS 4km data does not make sense, so the output data will have a subsampling rate 4.
Valid responses are [0,1,2,4,8]. The default is 4.
This specifies the rate of infrared channel subsampling. If small_ir_delta=4 every fourth sample of every fourth line will be used. If small_ir_delta=1, all samples and lines will be retained. Specifying small_ir_delta=0 indicates that the infrared data from the small infrared sensor should not be extracted/stored in the dataset.
Valid responses are [0,1,2]. The default is 1.
This specifies the rate of infrared channel subsampling. If large_ir_delta=4 every fourth sample of every fourth line will be used. If large_ir_delta=1, all samples and lines will be retained. Specifying large_ir_delta=0 indicates that the infrared data from the large infrared sensors should not be extracted/stored in the dataset.
Valid responses are [0,1,2]. The default is 1.
Answer yes if the data is to be selected from the intersection of a master dataset (1 in the description above, also see master). Answer no if subsets are to be specified by start spin and width (2 in description above).
Valid responses are [yes or no]. The default is yes.
If use_master=yes, this is the name of the master dataset used to specify a region for data extraction (see master).
Valid responses are any TeraScan dataset that contains an Earth transform. The default is Master.
If use_master=no, this is the spin (i.e. line) number to start saving data. This number is relative to the infrared resolution (spin numbers).
Valid responses are [1..2500]. The default is 1.
If use_master=no, this is the number of spins (i.e. lines) to retrieve. This number is relative to the infrared resolution (spin numbers) and in terms of unsampled spins. Thus if num_spins=500 and delta_vis=2 then the actual number of visible lines will be 250.
Valid responses are [1..2500]. The default is 2500.
If use_master=no, this is the percentage of the image to skip in the scan direction (i.e left to right) before saving data. Thus if start_percent=50, the retrieved image will begin halfway into the scan lines, i.e. at middle of the Earth, and consist of data to the right (east) of this starting point.
Valid responses are [0..<100]. The default is 0.
If use_master=no, this is the percentage of the image to skip in the scan direction (i.e left to right) before saving data. Thus if width_percent=50, the retrieved image will begin halfway into the scan lines, i.e. at middle of the Earth, and consist of data to the right (east) of this starting point.
Valid responses are [0..<100]. The default is 0.
Specifies record length by referring to one of the following ARMA GOES formats:
Format Name Record length Block type ----------- ------------- ---------- nev 96 NORMAL, Earth View (0) naux 1030 NORMAL, Auxiliary (1) nvis4 4430 NORMAL, VIS 4km (4-11) nvis2 8252 NORMAL, VIS 2km (4-11) call 11946 COMPACT, All (0-11) nir 11884 NORMAL, IR (2,3) nvis1 15896 NORMAL, VIS 1km (4-11) tscan - Standard TeraScan format The default value is tscan.
Asks whether to include the header information concerning calibration, etc. Valid responses are [yes and no]. The default is no.
[1] % master output file : char(255) ? [Master] projection : char( 13) ? st center_lat : char( 15) ? 40n center_lon : char( 15) ? 75w num_lines : int ? 1000 num_samples : int ? 800 pixel_width : real ? [1.1132] 2 pixel_height : real ? [1.1132] 2 rotate_angle : real ? [0] [2] % avasin output file(s) : char(255) ? [.] on_pass_disk : char( 3) ? [yes] no tape_device : char(255) ? [/dev/nwd0] first_file : int ? [1] num_files : int ? [1] vis_delta : char( 1) ? [8] 2 small_ir_delta : char( 1) ? [2] large_ir_delta : char( 1) ? [4] use_master : char( 3) ? [yes] master_file : char(255) ? [Master] save_common_doc: char( 3) ? [no] goes_format : char( 5) ? [tscan] nvis1 Is tape up ? y /dev/nwd0: Processing pass 1 block 2: spin(s) 1 - 98 missing block 3: spin(s) 1 - 98 missing VIS: Data Resolution 4 km VIS: visds increased to 4
refdata/coast/wdb2.cil 1 KM resolution coast/islands/lakes refdata/coast/wdb2.riv 1 KM resolution rivers refdata/coast/wdb2.bdy 1 KM international boundaries refdata/coast/wdb2.states 1 KM internal boundaries refdata/coast/wdb2.thin 10 KM reduced resolution wdb2.cil
fastreg, GOES satellite documentation
Last Update: $Date: 2002/02/09 02:51:55 $