Hi, since you're using GDAL VRT have you tried the "Scale" and "Offset" child elements for a VRTRasterBand? I'd guess, using
<VRTRasterBand band="1"> <Scale>-1.0</Scale> <Offset>360.0</Offset> ... </VRTRasterBand> might work for you. Regards, Andreas > -----Original Message----- > From: mapserver-users [mailto:[email protected]] > On Behalf Of Rousseau Lambert2, Louis-Philippe (EC) > Sent: Monday, March 05, 2018 2:46 PM > To: [email protected] > Subject: [mapserver-users] Wind direction files rotation using > CONNECTIONTYPE uvraster > > Hi all, > > What I'm trying to do: > > * I want to display wind arrows using 2 files: wind direction and > wind speed. I am using the "CONNECTIONTYPE uvraster" feature to display > our arrows. Because we don't have U and V wind vectors in the North- > South direction for some models, we use the WIND and WDIR files which > are respectively wind speed and wind direction (in the North-South > direction, or Earth relative). So as input for my layer in MapServer I > have a VRT where band 1 is the wind direction (from 0 to 360 degres) and > band 2 is the wind speed. Instead of letting MapServer calculates the > resulting arrows speed and direction I'm using the raw value of u ([u]) > as wind direction and the raw value of v ([v]) as my wind speed. So far > so good. > > > My problem is: > > * The arrow rotation is done using the ANGLE keyword and [u] (wind > direction). But the ANGLE rotates the arrows in the counter clockwise > direction while the wind direction files increase in a clockwise > direction... Because we are using wind direction and wind speed files > (raw values of [u] and [v]) we can't use the [uv_minus_angle] and I know > that MapServer docs says that no processing can be done on the ANGLE > feature. I know that I would have to do some pre-processing (like 360- > [u]) and that would solve the problem. But I would have to do this for > hundreds of file per day and I'm trying to avoid as much as possible > pre-processing. > > Can you guys think of a solution that would not require pre-processing? > I tried playing with the arrow position and other little things but I > could not make it work correctly and I'm pretty much out of ideas... > > > Thanks > > LP > _______________________________________________ mapserver-users mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/mapserver-users
