The DIRSIG team is working with Los Alamos National Laboratory (LANL) to integrate the Qwick Urban industrial Complex (QUIC) plume model in to DIRSIG.
Starting with version 4.0.6, the functionality to read in a QUIC gas concentration output will be available. The functionality is currently experimental, and the syntax is liable to change in future DIRSIG revisions. An example of an NH3 plume:
The CONCENTRATION_MAP indicates the QUIC output file. The MOLECULAR_WEIGHT allows DIRSIG to convert from the [g/m3] used by QUIC to the [ppm] used by DIRSIG. The MATERIAL_ID gives the entry in the materials database supplying the radiometric and thermal properties of the gas.
The RELEASE_TEMPERATURE, in kelvin, is a hack, compensating for the lack of temperature information supplied by QUIC. DIRSIG finds the concentration voxel with the highest temperature and considers that to be the release point. It then scales linearly based on the dilution factor between the RELEASE_TEMPERATURE and the ambient air temperature. This does not work well if the plume was generated using multiple release points, especially if there is more than one release point in a single voxel.
The INSERT_POINT is an optional parameter allowing the plume to be translated around the scene.
The final group of inputs are a hack to compensate for some design issues in DIRSIG's implementation of the concentration map reader. The user must manually specify the delta between voxels in each dimension, though the current release of QUIC only outputs voxels of uniform size. Also, the GRID_OFFSET indicates the starting point of the data. In the example shown above, the first line of the concentration file reads:
The x,y,z values of each line should be in the middle of the voxel, so the CFG specifies an offset of 3,3,0 (we have 1m voxels). Note that all distance units are in meters.
Some actual performance metrics: with a 243 x 311 x 48 plume (3.63 million voxels, 0.67 of which are nonempty), DIRSIG takes about 40 MB of memory and 34 minutes to render a 5-band (0.3-0.8, delta 0.1) 1024x1024 nadir image. This was run using a Mac Mini with a 1.42 GHz G4 processor and 1GB of RAM.
Starting with version 4.0.6, the functionality to read in a QUIC gas concentration output will be available. The functionality is currently experimental, and the syntax is liable to change in future DIRSIG revisions. An example of an NH3 plume:
PLUME {
QUIC_INSTANCE {
CONCENTRATION_MAP = quic.dat
MOLECULAR_WEIGHT = 17.03
MATERIAL_ID = 5
RELEASE_TEMPERATURE = 550
INSERT_POINT = 0,0,0
GRID_OFFSET = 3,3,0
DELTA_X = 1.0
DELTA_Y = 1.0
DELTA_Z = 1.0
}
}The CONCENTRATION_MAP indicates the QUIC output file. The MOLECULAR_WEIGHT allows DIRSIG to convert from the [g/m3] used by QUIC to the [ppm] used by DIRSIG. The MATERIAL_ID gives the entry in the materials database supplying the radiometric and thermal properties of the gas.
The RELEASE_TEMPERATURE, in kelvin, is a hack, compensating for the lack of temperature information supplied by QUIC. DIRSIG finds the concentration voxel with the highest temperature and considers that to be the release point. It then scales linearly based on the dilution factor between the RELEASE_TEMPERATURE and the ambient air temperature. This does not work well if the plume was generated using multiple release points, especially if there is more than one release point in a single voxel.
The INSERT_POINT is an optional parameter allowing the plume to be translated around the scene.
The final group of inputs are a hack to compensate for some design issues in DIRSIG's implementation of the concentration map reader. The user must manually specify the delta between voxels in each dimension, though the current release of QUIC only outputs voxels of uniform size. Also, the GRID_OFFSET indicates the starting point of the data. In the example shown above, the first line of the concentration file reads:
3.50 3.50 0.50 0.0000E+00
The x,y,z values of each line should be in the middle of the voxel, so the CFG specifies an offset of 3,3,0 (we have 1m voxels). Note that all distance units are in meters.
Some actual performance metrics: with a 243 x 311 x 48 plume (3.63 million voxels, 0.67 of which are nonempty), DIRSIG takes about 40 MB of memory and 34 minutes to render a 5-band (0.3-0.8, delta 0.1) 1024x1024 nadir image. This was run using a Mac Mini with a 1.42 GHz G4 processor and 1GB of RAM.
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