[mapserver-dev] Call for vote on RFC 78

[Daniel Morissette]

On 11-11-16 11:58 PM, Brent Fraser wrote:
> Alan,
>
> Any plans to allow for raster files containing direction values
> (http://polar.ncep.noaa.gov/waves_old/products.html#grib, esp Mean Wave
> Dir) instead of calculating it from components? Note: sample data
> available at ftp://polar.ncep.noaa.gov/pub/waves, e.g. nww3.WVDIR.grb
> (wave direction)
>

Brent,

The approach of using u and v bands allows for resampling, which is 
essential to the approach of rendering vector fields at various scales, 
and I don't think is possible with a raster of direction (angle) values.

i.e. as you zoom in and out, with u and v raster bands, you can average 
the u and v pixel values independently over an area and the average u 
and average v give you an accurate average vector for the area. However, 
I could be wrong, but I don't think you can resample and average the 
direction (angle) values over a block of pixels to get the same result.

It's late here, so maybe you can prove me wrong.

-- 
Daniel Morissette
http://www.mapgears.com/
Provider of Professional MapServer Support since 2000