Open maelle opened 2 years ago
I think I misread what the element vs complexType are, however I'm still wondering whether the metadata could help one see what's geographical (sf) vs not (data.frame).
DescribeFeatureType should target 0..* cardinality for typeNames , as part of the WFS spec, so in principle we should be able to implement it. Possibly the same for GetFeatures, but i can't work on it immediatly. In general DescribeFeatureType and GetFeature are not used on more than one typeNames, although it is possible in the standard model.
You can get information of feature type before doing Get Feature, you do it when finding/accessing a feature type where a DescribeFeatureType operation is done when triggering getDescription()
method.
For example
wfs <- WFSClient$new("https://www.fao.org/fishery/geoserver/wfs", "2.0.0", logger = "INFO")
fao_areas <- wfs$capabilities$findFeatureTypeByName("fifao:FAO_MAJOR")
fao_areas_desc <- fao_areas$getDescription(pretty = T)
Thank you!
Oh right and if none of the types is "geometry" then one can conclude it'll be a data.frame, correct?
Yes ows4R behaves like that. You can publish (in particular in Geoserver) geometryless data through WFS protocol, ows4R will retrieve a data.frame instead of a sf object.
You can still filter over the properties you want to be part of the output with the WFS propertyName
parameter. See below an exampe where I skip the geometry:
fao_areas_data = fao_areas$getFeatures(propertyName = "F_CODE,F_LEVEL")
Thanks!
Is this "type guessing before download" something that should happen in ows4R (like getTitle()
there could be getRType()
or so) or in EMODnetWFS?
The type
is the R type already. The guessing is done in https://github.com/eblondel/ows4R/blob/master/R/WFSFeatureTypeElement.R#L119. For backward compatibility reasons, I can't really change the method now so getType
will give the R type, but if you need the WFS type, I can add a method getNativeType
or something similar
fao_areas_desc <- fao_areas$getDescription(pretty = F)
will give you the raw list of WFSFeatureTypeElement from which you can apply the getType. The above with pretty = T is just a convenience to get tabular view over the feature type definition
I think by type I meant layer type actually. I.e. knowing in advance when we do getFeatures()
, if the resulting thing will be a data.frame or a sf. Sorry for getting this mixed up.
Example:
library("EMODnetWFS")
wfs <- emodnet_init_wfs_client(
service = "biology_occurrence_data"
)
#> Loading ISO 19139 XML schemas...
#> Loading ISO 19115 codelists...
#> Loading IANA mime types...
#> No encoding supplied: defaulting to UTF-8.
#> ✓ WFS client created succesfully
#> ℹ Service: 'http://geo.vliz.be/geoserver/Dataportal/wfs'
#> ℹ Version: '2.0.0'
layers <- emodnet_get_wfs_info(wfs)[["layer_name"]]
is_geom <- function(layer_name, wfs) {
layer <- wfs$capabilities$findFeatureTypeByName(sprintf("Dataportal:%s", layer_name))
geom <- any(layer$getDescription(pretty = T)$type == "geometry")
tibble::tibble(
layer = layer_name,
geom = geom
)
}
layers_info <- purrr::map_df(layers, is_geom, wfs = wfs)
knitr::kable(layers_info)
layer | geom |
---|---|
abiotic_observations | TRUE |
biotic_observations | TRUE |
eurobis-obisenv_basic | FALSE |
eurobis-obisenv_count | FALSE |
eurobis-obisenv_full | TRUE |
eurobis-obisenv | TRUE |
eurobis_grid_15m-obisenv | TRUE |
eurobis_grid_1d-obisenv | TRUE |
eurobis_grid_30m-obisenv | TRUE |
eurobis_grid_6m-obisenv | TRUE |
eurobis_points-obisenv | TRUE |
iucn_grid | TRUE |
abiotic_observations_count | FALSE |
biotic_observations_count | FALSE |
categories | FALSE |
categories_get_by_datatype | FALSE |
datafiches_get_by_datasource_and_dataorigin_and_datatype | FALSE |
dataorigin_get_by_datasource_and_datatype | FALSE |
dataportal_get_observations_where | TRUE |
dataproviders_get_by_datatype | FALSE |
datasets | FALSE |
eurobis | TRUE |
geoobjects | TRUE |
geoobjects_get_by_name | FALSE |
parameters | FALSE |
parameters_get_by_name_and_category | FALSE |
taxa | FALSE |
Created on 2022-03-11 by the reprex package (v2.0.1)
sf::st_read()
(that's used in ows4R) returns a data.frame.The context is that I'm wondering how we could get more info on what we're going to get before using
getFeatures()
itself.Thanks in advance!