Example of using BBOX() in cql_filter argument in emodnet_get_layers

[emodnet]

Example of using BBOX() in cql_filter argument in emodnet_get_layers

[annakrystalli]

Hey @salvafern. When you use the bbox predicate, you can supply a CRS which refers to the CRS the bbox coordinates are in, which could differ from the CRS the layers, as part of the cql_filter. It's completely separate to the crs argument. Have a look at the docs I linked to above.

[salvafern]

Ah ok good, didn't know! Thanks @annakrystalli

[annakrystalli]

Hello @JanJaapPoos ! ☺️

Indeed you can use the bbox filter like so:

emodnet_get_layers(service = "geology_seabed_substrate_maps", 
                   layers = "seabed_substrate_1m",
                   cql_filter = "BBOX(geom, 2565427, 4026324, 1522239, 2778536)",
                   reduce_layers = TRUE ) 

Note that geom is the name of the attribute that contains feature geometries, coordinates are supplied in the sequence xmin, xmax, ymin, ymax and the query default is to use the CRS of the queried layer unless an additional CRS argument is provided. See more detail here https://docs.geoserver.org/latest/en/user/filter/ecql_reference.html#spatial-predicate.

I'll also be updating the docs with much more detailed documentation shortly.

[JanJaapPoos]

Hi @annakrystalli,

Excellent, thanks.

[salvafern]

Hey @annakrystalli!

I wonder if providing a CRS via the crs argument would actually work since the CQL filter is applied in the WFS request but the reprojection is performed in the client side?

EMODnetWFS/R/layers.R

Line 135 in 1d170d5

sf <- sf::st_transform(sf, crs)

For that to work I think the reprojection would have to be requested with WFS instead of using sf. What do you think? 😶