>From: "Thomas Renkevens" <address@hidden>
>Organization: NOAA
>Keywords: 200210181813.g9IIDJ102051 NOAAPORT GINI compress
Tom, Fred, Kevin,
Oops. The standard deviation numbers I sent in my last email were
actually variances (std**2). The list below contains the correct
standard deviations.
I finally was able to free up enough time to compile some statistics on
the lossless PNG technique we use to compress NOAAPORT GINI images we
send in our IDD.
The following numbers represent NOAAPORT GINI imagery received between
23 Z Friday, October 25 to 23 Z Saturday, October 26. We compress the
images received in NOAAPORT before injecting them into our IDD. The
compressed images are uncompressed upon receipt at downstream hosts.
PNG Compression
GINI Product Mean Std Product Description
---------------------+------+-------+------------------------
AK-NATIONAL_VIS 2.285 0.352 Alaska Nat 8 km 0.65 um
AK-NATIONAL_WV 6.911 0.795 Alaska Nat 8 km 6.8 um
AK-NATIONAL_IR 3.001 0.409 Alaska Nat 8 km 10.7 um
AK-REGIONAL_VIS 1.718 0.162 Alaska Reg 2 km 0.65 um
AK-REGIONAL_3.9 1.962 0.040 Alaska Reg 8 km 3.9 um
AK-REGIONAL_WV 3.576 0.057 Alaska Reg 16km 6.8 um
AK-REGIONAL_IR 2.077 0.024 Alaska Reg 8 km 10.7 um
AK-REGIONAL_12.0 2.085 0.025 Alaska Reg 8 km 12.0 um
HI-NATIONAL_VIS 3.599 0.865 Hawaii Nat 14km 0.65 um
HI-NATIONAL_WV 8.813 2.105 Hawaii Nat 14km 6.8 um
HI-NATIONAL_IR 4.377 1.006 Hawaii Nat 14km 10.7 um
HI-REGIONAL_VIS 1.878 0.257 Hawaii Reg 1 km 0.65 um
HI-REGIONAL_3.9 2.616 0.375 Hawaii Reg 4 km 3.9 um
HI-REGIONAL_WV 3.947 0.511 Hawaii Reg 8 km 6.8 um
HI-REGIONAL_IR 2.688 0.342 Hawaii Reg 4 km 10.7 um
HI-REGIONAL_12.0 2.656 0.333 Hawaii Reg 4 km 12.0 um
PR-NATIONAL_VIS 2.341 0.922 P Rico Nat 8 km 0.65 um
PR-NATIONAL_WV 5.401 1.921 P Rico Nat 8 km 6.8 um
PR-NATIONAL_IR 2.920 1.172 P Rico Nat 8 km 10.7 um
PR-REGIONAL_VIS 2.159 0.533 P Rico Reg 1 km 0.65 um
PR-REGIONAL_3.9 2.858 0.756 P Rico Reg 4 km 3.9 um
PR-REGIONAL_WV 4.049 1.070 P Rico Reg 8 km 6.8 um
PR-REGIONAL_IR 2.918 0.781 P Rico Reg 4 km 10.7 um
PR-REGIONAL_12.0 2.896 0.763 P Rico Reg 4 km 12.0 um
PNG Compression
GINI Product Mean Std Product Description
---------------------+------+-------+------------------------
EAST-CONUS_VIS 1.947 0.173 East Conus 1 km 0.65 um
EAST-CONUS_3.9 2.203 0.069 East Conus 4 km 3.9 um
EAST-CONUS_WV 4.274 0.083 East Conus 8 km 6.8 um
EAST-CONUS_IR 2.544 0.974 East Conus 4 km 10.7 um
EAST-CONUS_12.0 2.515 0.054 East Conus 4 km 12.0 um
WEST-CONUS_VIS 1.857 0.113 West Conus 1 km 0.65 um
WEST-CONUS_3.9 2.295 0.052 West Conus 4 km 3.9 um
WEST-CONUS_WV 4.391 0.109 West Conus 8 km 6.8 um
WEST-CONUS_IR 2.518 0.082 West Conus 4 km 10.7 um
WEST-CONUS_12.0 2.487 0.069 West Conus 4 km 12.0 um
PNG Compression
GINI Product Mean Std Product Description
---------------------+------+-------+------------------------
NHEM-COMP_VIS 1.760 0.161 Nth Hemi 24km 0.65 um
NHEM-COMP_3.9 2.011 0.133 Nth Hemi 24km 3.9 um
NHEM-COMP_WV 3.429 0.245 Nth Hemi 24km 6.8 um
NHEM-COMP_IR 1.983 0.136 Nth Hemi 24km 10.7 um
NHEM-COMP_12.0 2.013 0.138 Nth Hemi 24km 12.0 um
NHEM-MULTICOMP_VIS 2.050 0.139 MultiSat 24km 0.65 um
NHEM-MULTICOMP_WV 2.809 0.111 MultiSat 24km 6.8 um
NHEM-MULTICOMP_IR 1.815 0.019 MultiSat 24km 10.7 um
SUPER-NATIONAL_VIS 1.583 0.018 SuprNatnl 8 km 0.65 um
SUPER-NATIONAL_3.9 1.959 0.040 SuprNatnl 8 km 3.9 um
SUPER-NATIONAL_WV 4.286 0.044 SuprNatnl 8 km 6.8 um
SUPER-NATIONAL_IR 2.051 0.019 SuprNatnl 8 km 10.7 um
SUPER-NATIONAL_12.0 2.073 0.018 SuprNatnl 8 km 12.0 um
SUPER-NATIONAL_CTP 6.148 0.703 SuprNatnl 8 km Cld Top Pres
SUPER-NATIONAL_LI 6.853 0.823 SuprNatnl 8 km Lifted Index
SUPER-NATIONAL_PW 6.789 0.818 SuprNatnl 8 km Precip Water
SUPER-NATIONAL_SFC-T 6.463 0.761 SuprNatnl 8 km Sfc Temp
As a comparison, the same numbers for various composites we create from
the NOAAPORT NEXRAD level III products is:
PNG Compression
GINI Product Mean Std Product Description
---------------------+------+-------+------------------------
RADAR_n0r 9.248 1.611 1 km N0R composite
RADAR_n1p 63.142 5.198 2 km N1P composite
RADAR_ntp 13.549 1.075 4 km NTP composite
Values in the 'Mean' column represent the average compression ratio
over the 24 hour ingest period, and values in the 'Std' column
represent the standard deviation of those compression ratios.
As you would expect for satellite imagery, VIS images compress the
least and water vapor compress the most. Compression ratios for
satellite products (e.g., CTP, LI, PW, and SFC-T) are all good.
I hope these numbers are useful.
Tom
>From address@hidden Mon Oct 28 05:25:39 2002
>CC: Frederick R Mosher <address@hidden>,
> Kevin Schrab <address@hidden>, address@hidden
>Subject: Re: 20021021: Unidata lossless PNG compression of NOAAPORT image
>products
Awesome! Thanks for the numbers and I will pass this information around.
Tom
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