geojsonR (version 1.1.1)

save_R_list_Features_2_FeatureCollection: creates a FeatureCollection from R list objects ( see the details section about the limitations of this function )

Description

creates a FeatureCollection from R list objects ( see the details section about the limitations of this function )

Usage

save_R_list_Features_2_FeatureCollection(
  input_list,
  path_to_file = "",
  verbose = FALSE
)

Value

a FeatureCollection in form of a character string

a FeatureCollection saved in a file

Arguments

input_list

a list object that includes 1 or more geojson R list Features

path_to_file

either an empty string ("") or a valid path to a file where the output FeatureCollection will be saved

verbose

a boolean. If TRUE then information will be printed out in the console

Details

• it allows the following attributes: 'type', 'id', 'properties' and 'geometry'

• it allows only coordinates of type 'Polygon' or 'MultiPolygon' to be processed. In case of a 'Polygon' there are 2 cases: (a.) Polygon WITHOUT interior rings (a numeric matrix is expected) and (b.) Polygon WITH interior rings (a list of numeric matrices is expected). See the test-cases if you receive an error for the correct format of the input data. In case of a 'MultiPolygon' both Polygons with OR without interior rings can be included. Multipolygons are of the form: list of lists where each SUBLIST can be either a numeric matrix (Polygon without interior rings) or a list (Polygon with interior rings)

• the properties attribute must be a list that can take only character strings, numeric and integer values of SIZE 1. In case that any of the input properties is of SIZE > 1 then it will throw an error.

The input_list parameter can be EITHER created from scratch OR GeoJson Features (in form of a FeatureCollection) can be loaded in R and modified so that this list can be processed by this function

Examples

if (FALSE) {

library(geojsonR)

#------------------------------------------------
# valid example that will save the data to a file
#------------------------------------------------

Feature1 = list(type ="Feature",
                id = 1L,
                properties = list(prop1 = 'id', prop2 = 1.0234),
                geometry = list(type = 'Polygon',
                                coordinates = matrix(runif(20), nrow = 10, ncol = 2)))

Feature2 = list(type ="Feature",
                id = 2L,
                properties = list(prop1 = 'non-id', prop2 = 6.0987),
                geometry = list(type = 'MultiPolygon',
                                coordinates = list(matrix(runif(20), nrow = 10, ncol = 2),
                                                  matrix(runif(20), nrow = 10, ncol = 2))))

list_features = list(Feature1, Feature2)

path_feat_col = tempfile(fileext = '.geojson')

res = save_R_list_Features_2_FeatureCollection(input_list = list_features,
                                               path_to_file = path_feat_col,
                                               verbose = TRUE)

#-------------------------------------
# validate that the file can be loaded
#-------------------------------------

res_load = FROM_GeoJson_Schema(url_file_string = path_feat_col)
str(res_load)


#----------------------------------------------------
# INVALID data types such as NA's will throw an ERROR
#----------------------------------------------------


Feature1 = list(type ="Feature",
                id = 1L,
                properties = list(prop1 = NA, prop2 = 1.0234),
                geometry = list(type = 'Polygon',
                                coordinates = matrix(runif(20), nrow = 10, ncol = 2)))

list_features = list(Feature1, Feature2)

path_feat_col = tempfile(fileext = '.geojson')

res = save_R_list_Features_2_FeatureCollection(input_list = list_features,
                                               path_to_file = path_feat_col,
                                               verbose = TRUE)
}