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Wording and typo fix for NEXRAD_Level_3_Plot_with_Matplotlib

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Michael James 2017-02-02 19:52:12 -07:00
parent 07ddf752a4
commit ce83b12d62
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examples/notebooks/NEXRAD_Level_3_Plot_with_Matplotlib.ipynb
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@ -17,19 +17,18 @@
" halfword 32 contains the increment in m/s*10 (or dBZ*10)\n",
" halfword 33 contains the number of levels (0 - 255) \n",
"\n",
"Here's something peculiar: according to the [ICD for the Product Specification](https://www.roc.noaa.gov/WSR88D/PublicDocs/NewTechnology/B17_2620003W_draft.pdf), *\"the 256 data levels of the digital product cover a range of reflectivity between -32.0 to +94.5 dBZ, in increments of 0.5 dBZ. Level codes 0 and 1 correspond to 'Below Threshold' and 'Range Folded', respectively, while level codes 2 through 255 correspond to the reflectivity data itself\"*.\n",
"According to the [ICD for the Product Specification](https://www.roc.noaa.gov/WSR88D/PublicDocs/NewTechnology/B17_2620003W_draft.pdf), *\"the 256 data levels of the digital product cover a range of reflectivity between -32.0 to +94.5 dBZ, in increments of 0.5 dBZ. Level codes 0 and 1 correspond to 'Below Threshold' and 'Range Folded', respectively, while level codes 2 through 255 correspond to the reflectivity data itself\"*.\n",
"\n",
"So it's really 254 color values between -32 and +94.5 dBZ.\n",
"\n",
"\n",
"The ICD lists 16 specific color levels and directs 256-level reflectivity products to use corresponding colors, leaving it the rendering application to scale and blend between the 16 color values, and to make decisions about discrete color changes, apparently.\n",
"![](http://i.imgur.com/cqphoe3.png)\n",
"\n",
"For AWIPS, the National Weather Server uses a mostly-blended color scale with a discrete jump to red at reflectivity values of 50 dBZ:\n",
"For AWIPS, the National Weather Service uses a mostly-blended color scale with a discrete jump to red at reflectivity values of 50 dBZ:\n",
" \n",
"![](http://i.imgur.com/o18gmio.png)\n",
"\n",
"50 dBZ corresponds to the 16-level code **A**, colored *light red* (**FF6060**). Note that `FF6060` is not used in the NWS AWIPS color scale, instead RGB value is given as `255,0,0` (or as percent `1.0,0.0,0.0`). 60 is not quite exactly where white starts, but it makes convenient sense enough I don't see a reason why not. Obviously the AWIPS D2D authors took some liberties with their 256-level rendering, not adhering to \"dark red\" for dBZ values between 60-65 (white was for 70 dBZ and above on the 16-level colormap). Still the goal is to follow operational AWIPS as closely as possible, and that means recreating the rendering of their DHR/N0Q plots to the colored pixel, so we will assume 50 dBZ should be red and 60 dBZ white, and 75 dBZ cyan."
"50 dBZ corresponds to the 16-level color *light red* (**FF6060**). Note that `FF6060` is not used in the NWS AWIPS color scale, instead RGB value is given as `255,0,0` (or as percent `1.0,0.0,0.0`). 60 is not quite exactly where white starts, but it makes convenient sense enough I don't see a reason why not. Obviously the AWIPS D2D authors took some liberties with their 256-level rendering, not adhering to \"dark red\" for dBZ values between 60-65 (white was for 70 dBZ and above on the 16-level colormap). Still the goal is to follow operational AWIPS as closely as possible, and that means recreating the rendering of their DHR/N0Q plots to the colored pixel, so we will assume 50 dBZ should be red and 60 dBZ white, and 75 dBZ cyan."
]
},
{