Issue70

NAMESPACE

@@ -1,15 +1,15 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method(df_geojson,data.frame)
-S3method(geojson_sf,character)
-S3method(geojson_sf,connection)
-S3method(geojson_sf,default)
-S3method(geojson_sf,geojson)
-S3method(geojson_sf,numeric)
-S3method(geojson_sfc,character)
-S3method(geojson_sfc,connection)
-S3method(geojson_sfc,default)
-S3method(geojson_sfc,geojson)
+S3method(geojson_to_sf,character)
+S3method(geojson_to_sf,connection)
+S3method(geojson_to_sf,default)
+S3method(geojson_to_sf,geojson)
+S3method(geojson_to_sf,numeric)
+S3method(geojson_to_sfc,character)
+S3method(geojson_to_sfc,connection)
+S3method(geojson_to_sfc,default)
+S3method(geojson_to_sfc,geojson)
 S3method(print,geojson)
 S3method(sf_geojson,default)
 S3method(sf_geojson,sf)

NEWS.md

@@ -1,6 +1,7 @@
 
 ## v1.3.2
 
+* `crs` and `proj4string` arguments to `geojson_sf` and `geojson_sfc` 
 * fix crash due to factor levels [issue 62](https://github.com/SymbolixAU/geojsonsf/issues/62)
 * fix invalid GeoJSON when NA elements [issue 63](https://github.com/SymbolixAU/geojsonsf/issues/63)
 

R/geojson_sf.R

@@ -4,6 +4,8 @@
 #'
 #' @param geojson string or vector of GeoJSON, or a URL or file pointing to a geojson file
 #' @param expand_geometries logical indicating whether to unnest GEOMETRYCOLLECTION rows. see details
+#' @param crs coordiante reference system. See Details
+#' @param proj4string proj4string. See Details
 #'
 #' @details
 #' specifying \code{expand_geometries = TRUE} will expand individual \code{GEOMETRYCOLLECTION}
@@ -13,6 +15,15 @@
 #' The \code{GEOMETRYCOLLECTION} information is not kept when using \code{expand_geometries = TRUE}. Therefore,
 #' it is not possible to reconstruct the \code{GEOMETRYCOLLECTION} after unnesting it.
 #'
+#' Geojson specification RFC7946 \link{https://tools.ietf.org/html/rfc7946#page-12}
+#' says all CRS should be the World Geodetic System 1984 (WGS 84) [WGS84] datum,
+#' with longitude and latitude units of decimal degrees.  This is equivalent to
+#' the coordinate reference system identified by the Open Geospatial Consortium (OGC)
+#' URN urn:ogc:def:crs:OGC::CRS84
+#'
+#' \code{geojson_sfc} and \code{geojson_sf} automatically set the CRS to WGS 84.
+#' The fields \code{crs} and \code{proj4string} let you to overwrite the defaults.
+#'
 #' @examples
 #'
 #' ## character string of GeoJSON
@@ -35,31 +46,40 @@
 #' }
 #'
 #' @export
-geojson_sfc <- function(geojson, expand_geometries = FALSE) UseMethod("geojson_sfc")
+geojson_sfc <- function(geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL) {
+	sfc <- geojson_to_sfc( geojson, expand_geometries )
+	if( !is.null( crs ) | !is.null( proj4string ) ) {
+		sfc <- set_crs( sfc, crs, proj4string )
+	}
+	return( sfc )
+}
 
+geojson_to_sfc <- function( geojson, expand_geometries ) UseMethod("geojson_to_sfc")
 
 #' @export
-geojson_sfc.geojson <- function( geojson, expand_geometries = FALSE) geojson_sfc.character(geojson, expand_geometries)
+geojson_to_sfc.geojson <- function( geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL) {
+	geojson_to_sfc.character(geojson, expand_geometries)
+}
 
 #' @export
-geojson_sfc.character <- function(geojson, expand_geometries = FALSE) {
+geojson_to_sfc.character <- function(geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL) {
 
 	if(length(geojson) > 1) {
 		return(rcpp_geojson_to_sfc(geojson, expand_geometries))
 	}
 	if (is_url(geojson)) {
-		return(geojson_sfc(curl::curl(geojson), expand_geometries))
+		return(geojson_to_sfc(curl::curl(geojson), expand_geometries))
 	} else if (file.exists(geojson) ) {
 		return(rcpp_read_sfc_file(normalizePath(geojson), expand_geometries))
 	}
 	return(rcpp_geojson_to_sfc(geojson, expand_geometries))
 }
 
 #' @export
-geojson_sfc.connection <- function(geojson, expand_geometries = FALSE) geojson_sfc(read_url(geojson), expand_geometries)
+geojson_to_sfc.connection <- function(geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL) geojson_sfc(read_url(geojson), expand_geometries)
 
 #' @export
-geojson_sfc.default <- function(geojson, expand_geometries = FALSE) rcpp_geojson_to_sfc(geojson, expand_geometries)
+geojson_to_sfc.default <- function(geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL) rcpp_geojson_to_sfc(geojson, expand_geometries)
 
 #' Geojson to sf
 #'
@@ -83,39 +103,65 @@ geojson_sfc.default <- function(geojson, expand_geometries = FALSE) rcpp_geojson
 #'
 #' @inherit geojson_sfc params details
 #' @export
-geojson_sf <- function(geojson, expand_geometries = FALSE) UseMethod("geojson_sf")
+geojson_sf <- function(geojson, expand_geometries = FALSE, crs = NULL, proj4string = NULL ) {
+	sf <- geojson_to_sf( geojson, expand_geometries )
+	if( !is.null( crs ) | !is.null( proj4string ) ) {
+		sf[["geometry"]] <- set_crs( sf[["geometry"]], crs, proj4string )
+	}
+	return( sf )
+}
+
+geojson_to_sf <- function( geojson, expand_geometries ) {
+	UseMethod("geojson_to_sf")
+}
 
 #' @export
-geojson_sf.geojson <- function( geojson, expand_geometries = FALSE) geojson_sf.character(geojson, expand_geometries)
+geojson_to_sf.geojson <- function( geojson, expand_geometries = FALSE) {
+	geojson_to_sf.character(geojson, expand_geometries)
+}
 
 #' @export
-geojson_sf.character <- function(geojson, expand_geometries = FALSE) {
+geojson_to_sf.character <- function(geojson, expand_geometries = FALSE) {
 
 	if(length(geojson) > 1) {
 		return(rcpp_geojson_to_sf(geojson, expand_geometries))
 	}
 	if (is_url(geojson)) {
-		return(geojson_sf(curl::curl(geojson), expand_geometries))
+		return(geojson_to_sf(curl::curl(geojson), expand_geometries))
 	} else if (file.exists(geojson) ) {
 		return(rcpp_read_sf_file(normalizePath(geojson), expand_geometries))
 	}
 	 return(rcpp_geojson_to_sf(geojson, expand_geometries))
 }
 
 #' @export
-geojson_sf.connection <- function(geojson, expand_geometries = F) geojson_sf(read_url(geojson), expand_geometries)
+geojson_to_sf.connection <- function(geojson, expand_geometries = F) {
+	geojson_sf(read_url(geojson), expand_geometries)
+}
 
 #' @export
-geojson_sf.numeric <- function(geojson, ... ) stop("Numeric vectors are not valid GeoJSON")
+geojson_to_sf.numeric <- function(geojson, ... ) stop("Numeric vectors are not valid GeoJSON")
 
 #' @export
-geojson_sf.default <- function(geojson, expand_geometries = F) rcpp_geojson_to_sf(geojson, expand_geometries)
-
+geojson_to_sf.default <- function(geojson, expand_geometries = F) {
+	rcpp_geojson_to_sf(geojson, expand_geometries)
+}
 
 
 
 date_columns <- function( sf ) names(which(vapply(sf , function(x) { inherits(x, "Date") | inherits(x, "POSIXct") }, T)))
 
+set_crs <- function(sfc, crs, proj4string ) {
+	crs <- list(
+		epsg = ifelse(is.null(crs),NA_integer_,crs)
+		, proj4string = ifelse(is.null(proj4string),"",proj4string)
+	)
+	attr( crs, "class" ) <- "crs"
+	attr( sfc, "crs" ) <- crs
+	return( sfc )
+}
+
+
 handle_dates <- function( x ) {
 	dte <- date_columns( x )
 	x[dte] <- lapply(as.data.frame(x)[dte], as.character)

README.Rmd

@@ -28,7 +28,7 @@ A simple, low-dependency and **fast** converter between GeoJSON and Simple Featu
 
 ---
 
-**v1.2.1** 
+**v1.3.2** 
 
 Converts
 
@@ -41,6 +41,16 @@ Converts
 
 As per GeoJSON ([RFC 7946 specification)](https://tools.ietf.org/html/rfc7946#page-11), foreign members are ignored, and nested objects and arrays inside the `properties` object are converted to string/characters. 
 
+Also, as per the specification, **CRS** 
+
+> The coordinate reference system for all GeoJSON coordinates is a
+geographic coordinate reference system, using the World Geodetic
+System 1984 (WGS 84) [WGS84] datum, with longitude and latitude units
+of decimal degrees. This is equivalent to the coordinate reference
+system identified by the Open Geospatial Consortium (OGC) URN
+urn:ogc:def:crs:OGC::CRS84
+
+From **v1.3.2**, if your coordinates are in a different CRS you can specify the CRS & proj4string values in the `geojson_sf()` and `geojson_sfc()` functions. 
 
 ## Installation
 
@@ -144,7 +154,7 @@ sf_geojson(sf, simplify = F)
 
 This benchmark shows a comparison with `library(sf)` for converting a string of GeoJSON of 3,221 counties in the US in to an `sf` object
 
-```{r, warning=FALSE}
+```{r,eval= FALSE}
 myurl <- "http://eric.clst.org/assets/wiki/uploads/Stuff/gz_2010_us_050_00_500k.json"
 geo <- readLines(myurl)
 geo <- paste0(geo, collapse = "")
@@ -160,6 +170,11 @@ microbenchmark(
     },
     times = 2
 )
+
+#Unit: milliseconds
+#      expr       min        lq      mean    median        uq       max  neval
+# geojsonsf  709.2268  709.2268  722.0626  722.0626  734.8984  734.8984      2
+#        sf 1867.6840 1867.6840 1958.7968 1958.7968 2049.9097 2049.9097      2
 ```
 
 ### Does it work?
@@ -184,10 +199,7 @@ google_map() %>%
 knitr::include_graphics("./man/figures/GeoJSONSF.png")
 ```
 
-```{r}
-sf <- sf::st_read(geo, quiet = T)
-plot(st_geometry(sf[!sf$STATE %in% c("02", "15", "72"), ]))
-```
+
 
 
 

README.md

@@ -21,7 +21,7 @@ Simple Feature objects in R.
 
 -----
 
-**v1.2.1**
+**v1.3.2**
 
 Converts
 
@@ -37,6 +37,19 @@ specification)](https://tools.ietf.org/html/rfc7946#page-11), foreign
 members are ignored, and nested objects and arrays inside the
 `properties` object are converted to string/characters.
 
+Also, as per the specification, **CRS**
+
+> The coordinate reference system for all GeoJSON coordinates is a
+> geographic coordinate reference system, using the World Geodetic
+> System 1984 (WGS 84) \[WGS84\] datum, with longitude and latitude
+> units of decimal degrees. This is equivalent to the coordinate
+> reference system identified by the Open Geospatial Consortium (OGC)
+> URN <urn:ogc:def:crs:OGC>::CRS84
+
+From **v1.3.2**, if your coordinates are in a different CRS you can
+specify the CRS & proj4string values in the `geojson_sf()` and
+`geojson_sfc()` functions.
+
 ## Installation
 
 Install the CRAN version with
@@ -154,8 +167,7 @@ sf_geojson(sf, simplify = F)
 ### How fast is it?
 
 This benchmark shows a comparison with `library(sf)` for converting a
-string of GeoJSON of 3,221 counties in the US in to an `sf`
-object
+string of GeoJSON of 3,221 counties in the US in to an `sf` object
 
 ``` r
 myurl <- "http://eric.clst.org/assets/wiki/uploads/Stuff/gz_2010_us_050_00_500k.json"
@@ -173,13 +185,11 @@ microbenchmark(
     },
     times = 2
 )
-#  Unit: milliseconds
-#        expr       min        lq      mean    median        uq       max
-#   geojsonsf  709.2268  709.2268  722.0626  722.0626  734.8984  734.8984
-#          sf 1867.6840 1867.6840 1958.7968 1958.7968 2049.9097 2049.9097
-#   neval
-#       2
-#       2
+
+#Unit: milliseconds
+#      expr       min        lq      mean    median        uq       max  neval
+# geojsonsf  709.2268  709.2268  722.0626  722.0626  734.8984  734.8984      2
+#        sf 1867.6840 1867.6840 1958.7968 1958.7968 2049.9097 2049.9097      2
 ```
 
 ### Does it work?
@@ -205,10 +215,3 @@ google_map() %>%
 ```
 
 <img src="./man/figures/GeoJSONSF.png" width="100%" />
-
-``` r
-sf <- sf::st_read(geo, quiet = T)
-plot(st_geometry(sf[!sf$STATE %in% c("02", "15", "72"), ]))
-```
-
-<img src="man/figures/README-unnamed-chunk-12-1.png" width="100%" />