Hi, I am tagging along this thread as I’m also very interested to see if there is a simple answer to fix this behaviour 😊 This is also an issue we had with using UVRaster connection in MapServer with non-global weather models on our side.
Luckily for us, we also have access to the wind direction and wind speed variables for our non-global models and ending up using those variables instead, because the wind speed and direction are corrected properly to be relative to the North instead of using the wind vector components (U and V) which are always relative to the model’s grid axis. For this we needed to update the styles, we were using though as it is not the regular use for the UVRaster connection type. Because we are passing the wind direction and speed directly and variables, we are using the U and V values accordingly for the styles. In our case U becomes the speed and V the direction instead of using uv_length and uv_angle. MapServer class example: CLASS NAME "0 - 5 kts" EXPRESSION ([v] > 0.00 AND [v] <= 5) STYLE COLOR 0 0 127 SYMBOL "arrow_wind" ANGLE [u] SIZE 12 END END For your curiosity, here is a layer example using this method in our viewer MSC AniMet<https://eccc-msc.github.io/msc-animet/?layers=RDPS_10km_Winds_10m;0.75;0;1;WindBarbs_Sfc;1&extent=-9741945,4535177,-6122844,8024751&overlays=Boundaries&range=84,5,l,PT1H> Maybe this could also be useful on your side ? LP -- Louis-Philippe Rousseau-Lambert, B.Sc. Spécialiste en géomatique / Geomatics Specialist Systèmes de données géospatiales et ouvertes Geospatial and Open Data Systems Service Météorologique du Canada Meteorological Service of Canada Environnement et Changement Climatique Canada Environment and Climate Change Canada [email protected] (438) 801-0599 From: MapServer-users <[email protected]> On Behalf Of Alistair Everett via MapServer-users Sent: Monday, October 6, 2025 6:17 AM To: Seth G <[email protected]> Cc: MapServer Users <[email protected]> Subject: Re: [MapServer-users] UVRASTER reprojection Hi Seth, Thanks for your reply, we're just reprojecting the data. I'll take a closer look at the test case too, since it seems like that should be reprojecting from stereographic to geographic. I should also be able to pull together some test data in the next few days too, I can open an issue with it when I've put it together. Here are a couple of example requests: One in EPSG:4326 localhost:8000/wms?REQUEST=GetMap&SERVICE=WMS&VERSION=1.3.0&FORMAT=image%2Fpng&STYLES=wind_barb&TRANSPARENT=TRUE&TIME=2025-10-06T07%3A00%3A00Z&DIM_PRESSURE=50.0&DIM_REFERENCE_TIME=2025-10-06T03%3A00%3A00Z&LAYERS=wind_pl_vector_meps_det_vdiv_2_5km_calculations&WIDTH=1304&HEIGHT=1504&CRS=EPSG%3A3857&BBOX=-2460529.2703191666%2C4596419.518351211%2C6809846.057963322%2C15288631.55342549 https://pasteboard.co/jI1eMKaj3PT1.png This is one in EPSG:3411: localhost:8000/wms?REQUEST=GetMap&SERVICE=WMS&VERSION=1.3.0&FORMAT=image%2Fpng&STYLES=wind_barb&TRANSPARENT=TRUE&TIME=2025-10-06T16%3A00%3A00Z&DIM_PRESSURE=50.0&DIM_REFERENCE_TIME=2025-10-06T03%3A00%3A00Z&LAYERS=wind_pl_vector_meps_det_vdiv_2_5km_calculations&WIDTH=1438&HEIGHT=1504&CRS=EPSG%3A3411&BBOX=404935.5094684181%2C-3769428.4764078585%2C4977748.7994076125%2C1013263.5876175575 https://pasteboard.co/IHZjgXibtLyJ.png Thanks, Alistair On Sun, 5 Oct 2025 at 10:00, Seth G <[email protected]<mailto:[email protected]>> wrote: Hi Alistair, Could you give an example request (I presume it is WMS?)? Are you rotating your map at all, or is it just the projection? There are some tests which reproject a UVRASTER LAYER at https://github.com/MapServer/MapServer/blob/29e4ae81620a2c50201101c763df0b9d8d540b67/msautotest/wxs/wms_uvraster_map_reprojection.map It sounds like an oversight, so if you are able to create a standalone test case, it would be worth opening an issue. Seth -- web:https://geographika.net<https://geographika.net/> & https://mapserverstudio.net<https://mapserverstudio.net/> mastodon: @[email protected]<mailto:[email protected]> On Fri, Oct 3, 2025, at 11:59 AM, Alistair Everett via MapServer-users wrote: Hi all, I'm trying to use the UVRASTER connection to plot wind barbs. I noticed if I request the layer in a different projection the location of the arrows are reprojected but the angle, and presumably vector components, are not - rather they remain in the same direction relative to my screen. It's a little unclear from the documentation if this is the expected behaviour for UVRASTER or not? I included a pasteboard link to a screenshot to show what I mean, compare for example vectors in the corners of the data and you will see they point in the same direction relative to my screen, rather than being rotated to match the projection. If this is expected, does anyone have any suggested ways of working around this? If this is not expected, does anyone have any ideas what I've done wrong? I can provide some sample data if someone wants to try to reproduce. I'm using: MapServer version 8.4.0 PROJ version 9.4 GDAL version 3.11 OUTPUT=PNG OUTPUT=JPEG SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=FREETYPE SUPPORTS=CAIRO SUPPORTS=ICONV SUPPORTS=FRIBIDI SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=SOS_SERVER SUPPORTS=OGCAPI_SERVER SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS SUPPORTS=PBF INPUT=JPEG INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE INPUT=FLATGEOBUF Screenshot: https://pasteboard.co/WTgbexDmQaAe.png Example mapfile: https://pastebin.com/ibPc6gVK Thanks, Alistair ----------------------------- Dr Alistair Everett Senioringeniør / Senior Software Engineer Avdeling for Geoutvikling Phone: +47 939 68 985 Email: [email protected]<mailto:[email protected]> Meteorologisk Institutt, Henrik Mohns plass 1, 0313 Oslo ----------------------------- Dr Alistair Everett Senioringeniør / Senior Software Engineer Avdeling for Geoutvikling Phone: +47 939 68 985 Email: [email protected]<mailto:[email protected]> Meteorologisk Institutt, Henrik Mohns plass 1, 0313 Oslo _______________________________________________ MapServer-users mailing list [email protected]<mailto:[email protected]> https://lists.osgeo.org/mailman/listinfo/mapserver-users
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