Unit conversion in Gibson Ridge velocity and storm relative velocity products

If you don’t like the units displayed on your GR base velocity/storm relative velocity products, you can change them easily! Photo courtesy: NWS

Recently, a friend messaged me and said that the units on BV and SRV in the GRx programs are meters per second, instead of the desired knots, or MPH. This is correct. If you want knots or MPH, you need some things at the top of your customized velocity color table/palette file you are using to properly convert the default units. First, go into  C:, then Program Files (x86). Then head to  Program Files (x86), GRlevelX, then GRLevel3_2 (or the GR product you are using), and then ColorTables. These are the default color palettes that GR3, in this example, are using.

For base velocity, as an example:

Product: BV
Units: KTS
Step: 5
Scale: 1.9426 ; converts internal units (M/S) to KTS

For storm-relative velocity:

Product: SRV
Units: KTS
Step: 5
Scale: 1.9426 ; converts internal units (M/S) to KTS

Make sure you have that right at the top of your file, or your velocity couplets will be muted.
LIke so (this is my NWS storm relative velocity table, nws_velocity.pal; note that I have commented out knots as units, and just use MPH):

Product: SRV
;Units: KTS
Units: MPH
Step: 5
;Scale: 1.9426 ; converts internal units (M/S) to KTS
Scale: 2.2369 ; converts internal units (M/S) to MPH

RF: 134 0 134
ND: 0 0 0

Color: -120 30 30 255 240 240 255
Color: -70 240 253 240 8 222 8
Color: -30 8 197 8 16 132 16
Color: -20 16 115 16 16 115 16
Color: -15 25 99 25 25 99 25
Color: -10 41 107 41 41 107 41
Color: -5 58 107 56 107 123 107
Color: 0 140 124 140 120 0 0
Color: 4 123 0 0 123 0 0
Color: 14 160 0 0 205 105 125
Color: 40 205 105 125 255 240 240
Color: 60 255 247 240 255 152 0
Color: 120 255 109 0

Save the file to a different name. Due to permissions, you may have to save the file in a different folder, like your Documents folder. I made a grlevelx subdirectory in my Documents folder where I have all my customized color tables. Then, after changing the file, you will need to go to View -> Color Table Settings and select the new file, which loads the new table with your changes.

In the example color table above, I realize that the color values aren’t optimized for MPH (I might increase the higher values above 120 MPH), but this really helps velocity couplets stand out.

Got your own favorite? Head to the GRLevelx owner forums and share!

http://www.grlevelx.com/owners

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