When retrieving a number of data-points, but the kind of coordinate
reference system (CRS
) is not provided/known (for any
reason), the inborutils::guess_crs
function plots the data
for different projections on a map to make comparison possible. The main
function is guess_crs
which creates the map with different
options. The transform_coordinates
function can be useful
as well, as it supports conversion and transformation of coordinate
columns in a data.frame
.
This function only tries a selection of CRS
commonly
used in Belgium. We refer the user to the crsuggest
package
which has a function by the same name crsuggest::guess_crs
,
but is more generally applicable.
The aim is to quickly check the coordinate system by plotting the coordinates on a leaflet map with a list of given coordinate systems.
In order to run the functionalities, some R packages need to be
installed. The set of required libraries is handled by the
inborutils
package itself.
Loading the functionality can be done by loading the
inborutils
package:
CRS
functionThe guess_crs
function requires as minimal inputs:
data.frame
For example:
# my_dataframe has the columns "longitude" and "latitude"
guess_crs(coordinate_example, "longitude", "latitude")
## Warning in transform_coordinates(df, col_x, col_y, st_crs(prj), st_crs(4326)):
## Input CRS equal to output CRS No transform performed.
Furthermore, the optional argument belgium
is a boolean
value (TRUE/FALSE) defining if the data is expected to be in Belgium.
Finally, the epsg
codes of the corresponding coordinate
systems to check can be customised.
By default, the following CRS
-systems are tested:
EPSG:4326
EPSG:31370
EPSG:28992
EPSG:32631
EPSG:3812
EPSG:3035
Which can be overridden by adapting the projections
argument:
guess_crs(coordinate_example, "longitude", "latitude", belgium = TRUE,
crs_try = c("EPSG:2000", "EPSG:2805", "EPSG:4326"))
## Warning in transform_coordinates(df, col_x, col_y, st_crs(prj), st_crs(4326)):
## Input CRS equal to output CRS No transform performed.
Check the spatial reference for the available codes.