transform_projection: transform_projection

In konradmayer/trlboku: Tree Ring Lab BOKU - a lab internal R function collection

Description

Transforms to different projection by supplying an EPSG code. If object has no proj4string defined, old projection can be specified by argument epsg_old.

EPSG of common projections:

• WGS84: 4326

• Lambert Austria: 31287

Usage

transform_projection(spatial_object, epsg_new, epsg_old = NULL)

Arguments

spatial_object	an object of class "Spatial".
epsg_new	an EPSG code provided as character string indicating the desired projection for the returned object.
epsg_old	optional, an EPSG code provided as character string specifying the projection before transformation if no proj4string is supplied with the object.

Value

an object of class "Spatial".

Examples

## Not run: 
#library('sp')
init_dataframe <- data.frame(Y = c(48.6476, 48.6447, 48.6709),
                             X = c(16.7958, 6.7962, 16.5370),
                             meta = c('a', 'b', 'c'))
spatpoints <- SpatialPointsDataFrame(init_dataframe[c('X', 'Y')],
                                       init_dataframe['meta'])

## using other_projection():
spatpoints_lambert <- transform_projection(spatial_object, '31287',
epsg_old = '4326')

## using "manual approach":
# specify current projstring as WGS 84
proj4string(spatpoints) <- CRS("+init=epsg:4326")
# creator function for CRS class - set as Lambert-projection Austria
CRS.new <- CRS("+init=epsg:31287")
#transform spatialpointsto new projection
spatpoints_lambert2 <- spTransform(spatpoints, CRS.new)

#they are the same
identical(spatpoints_lambert, spatpoints_lambert2)

## End(Not run)

konradmayer/trlboku documentation built on July 3, 2020, 9:49 p.m.