geom
Transform a spatial object to class geom
gc_geom(input, ...)# S4 method for Spatial
gc_geom(input = NULL, ...)
# S4 method for sf
gc_geom(input = NULL, group = FALSE, ...)
# S4 method for Raster
gc_geom(input = NULL, stack = FALSE, group = FALSE, as_hex = FALSE, ...)
the object to transform to class geom
.
additional arguments.
[logical(1)
] should the values of a Raster* or the
attributes of MULTI* features be grouped, i.e., should the unique values be
assigned into the groups table (TRUE
)? The default behaviour for
Raster* would be not to assign values into the group attribute table if no
RAT is available and for MULTI* features it would be to keep the attributes
as duplicated per-feature attributes (FALSE
)?
[logical(1)
] should the layers of gridded objects be
stacked, i.e., should several layers be stored as columns in the attribute
table of features of one geom (TRUE
, default), or should they be
stored in (a list of) several geoms separately (FALSE
)?
[logical(1)
] should the bands 'red', 'green' and
'blue' of a gridded object be transformed to hexadecimal values
(TRUE
), or should they be retained as columns in a stacked grid geom
(FALSE
, default)?.
an object of class geom
When transforming a simple feature to a geom, all MULTI* features
are organised on a per feature basis, where the attribute table of features
in the geom contains those variables that are valid for each feature, while
the attribute table of groups contains those variables, that are unique
only at the level of groups of features (i.e., at the level of MULTI*
simple features). Those variables that are valid at the level of groups
would be duplicated in the attribute table of features. When a MULTI*
feature is transformed to a geom, the default behaviour is to copy the
simple feature as closely as possible. However, to reduce the object size
(and improve its' organisation), it is possible to assign the attributes of
groups into the attribute table of groups of the geom by setting
group = TRUE
.
When transforming a Raster* (or possibly other gridded classes) with
several layers to a geom, the layers are by default organised into a list
with a layer per list item. However, when several layers contain
fundamentally the same data (i.e., values that are associated to the same
groups), layers could be stacked stack = TRUE
, because they share
the same group attribute table.
# NOT RUN {
gc_geom(input = gtSF$polygon)
gc_geom(input = gtRasters$categorical)
# }
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