opengribs / XyGrib

This is the new home for the development of zyGrib
https://opengribs.org
GNU General Public License v3.0
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When no colour map is selected, wind bars are only shown at 10m and not at other available altitudes #250

Open norulz opened 4 years ago

norulz commented 4 years ago

We seem to have a logic issue when no colour map is selected it is not possible to show altitude wind barbs.

To replicate: GFS surface data - wind (10m), RH (2m), Temp (2m); Altitude 500mb and 700mb.

With the "Weather Map" set for wind, rh or temp, it is possible to select the altitude levels that are contained in the grib file. If no weather map is selected all the isoline altitude possibilities are available but not the general "Altitude" levels as these correspond with the weather colour maps to be shown.

Problem is the wind bars are only shown at 10m with no colour map

Two possible fixes:

  1. Let the altitude selector active if altitude data exists without condition of a colour weather map being selected or not
  2. Create an additional altitude selector specifically for wind barbs
dominiquehausser commented 4 years ago

Solution 1 is simple. Solution 2 is interesting as an extension of the wind jet stream colors (mainly useful at altitude 200 hPa). In this case try to keep a scale where difference of color remain relatively easy to distinguish graduation with color change and moving the scale according to the distribution of wind speed. Meaning creating scales for each altitude. As visual impact is quite high, users must be aware that the color value change when altitude change (a slight increased risk of misinterpretation, slight because generally those who look at altitude data have more training in meteo data reading than the majority of "regular" users).

Small remark : gust value given is always at 10 meters, even if wind speed is given for another altitude - 2 ways to solve it : label is modified to mention 10 m or data is not shown when using other altitudes.

dominiquehausser commented 4 years ago

Interesting tool to help to choose colors and colors scale https://vis4.net/palettes/#/19|d|00429d,96ffea,ffffe0|ffffe0,ff005e,93003a|1|1