[MapServer-users] Is it possible to wrap GeoJSON over multiple globes when using OGR connection type?

[Pelletier,Étienne (ECCC)]

Sorry, the above example WMS GetMap URL is incorrect (doh!). The correct one is as follows:


http://geo.weather.gc.ca./geomet?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&LAYERS=RADAR_COVERAGE_RSNO.INV&STYLES=&CRS=EPSG%3A4326&WIDTH=2560&HEIGHT=893&BBOX=-85,-180,85,360<http://geo/?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&LAYERS=RADAR_COVERAGE_RSNO.INV&STYLES=&CRS=EPSG%3A4326&WIDTH=2560&HEIGHT=893&BBOX=-85,-180,85,360>


That'll teach me to always re-read my emails... or not!

Etienne

________________________________
From: MapServer-users <mapserver-users-bounces at lists.osgeo.org> on behalf of Pelletier,Étienne (ECCC) via MapServer-users <mapserver-users at lists.osgeo.org>
Sent: January 30, 2024 8:45 AM
To: mapserver-users at lists.osgeo.org <mapserver-users at lists.osgeo.org>
Subject: [MapServer-users] Is it possible to wrap GeoJSON over multiple globes when using OGR connection type?

Hi,

We often use single-image requests when generating animations from WMS GetMap images via the use of OpenLayer's ImageWMS source. In many cases, the user may make a request for an image that contains a wrapped globe. In most cases, MapServer is able to handle these requests correctly but we have noticed an issue with a simple EPSG:4326 GeoJSON.

See the following request as an example:
http://geomet-dev-22.cmc.ec.gc.ca:8020/?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&LAYERS=RADAR_COVERAGE_RSNO.INV&STYLES=&CRS=EPSG%3A4326&WIDTH=2560&HEIGHT=893&BBOX=-85,-180,85,360

The PROJECTION directive in the mapfile is defined as such:

PROJECTION
 "proj=longlat"
 "datum=WGS84"
 "no_defs"
END

For a similar GeoTIFF with the same projection, adding the lon_wrap=-180 parameter to the proj4 string does the trick and allows the data to be displayed on these "multi-globe" single-image requests. See the following which image which has the following PROJECTION directive defined:

https://pasteboard.co/DPK1uNvyEKTd.png

PROJECTION
 "proj=longlat"
 "datum=WGS84"
 "lon_wrap=-180"
 "no_defs"
END

Is this simply not interpreted the same way for OGR connections? Thanks in advance!


Etienne Pelletier,

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

(514)464-6772
etienne.pelletier at ec.gc.ca<mailto:etienne.pelletier at ec.gc.ca>


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