has_qgis function

Check availability of QGIS, a plugin, a provider or an algorithm

has_qgis() checks whether the loaded qgisprocess cache is populated, which means that a QGIS installation was accessible and responsive when loading the package. qgis_has_plugin(), qgis_has_provider() and qgis_has_algorithm() check for the availability of one or several plugins, processing providers and algorithms, respectively. They are vectorized.

has_qgis()

qgis_has_plugin(plugin, query = FALSE, quiet = TRUE)

qgis_has_provider(provider, query = FALSE, quiet = TRUE)

qgis_has_algorithm(algorithm, query = FALSE, quiet = TRUE)

Arguments

• plugin: A plugin name (e.g., "native"). Can be a vector of names.
• query: Use TRUE to refresh the cached value.
• quiet: Use FALSE to display more information, possibly useful for debugging.
• provider: A provider name (e.g., "native"). Can be a vector of names.
• algorithm: A qualified algorithm name (e.g., "native:buffer"). Can be a vector of names.

Returns

A logical, with length 1 in case of has_qgis().

Note

Only plugins that implement processing providers are supported.

Examples

has_qgis()
if (has_qgis()) qgis_has_algorithm("native:filedownloader")
if (has_qgis()) qgis_has_provider("native")
if (has_qgis()) qgis_has_plugin(c("grassprovider", "processing_saga_nextgen"))

See Also

Other topics about reporting the QGIS state: qgis_algorithms(), qgis_path(), qgis_using_json_input()