Projection of coordinate matrices
project.RdInterface to the PROJ.4 library of projection functions for geographical position data, no datum transformation possible. Use spTransform() for extended support.
project(xy, proj, inv = FALSE, use_ob_tran=FALSE, legacy=TRUE, allowNAs_if_not_legacy=FALSE, coordOp = NULL, verbose = FALSE, use_aoi=TRUE)
Arguments
| xy | 2-column matrix of coordinates |
|---|---|
| proj | character string of projection arguments; the arguments must be entered exactly as in the PROJ.4 documentation, in particular there cannot be any white space in +<arg>=<value> strings, and successive such strings can only be separated by blanks. |
| inv | default FALSE, if TRUE inverse projection to geographical coordinates |
| use_ob_tran | default FALSE, if TRUE and “+proj=ob_tran”, use General Oblique Transformation with internalised from/to projection reversal; the user oblique transforms forward rather than inverse. |
| legacy | default TRUE, if FALSE, use transform C functions (enforced internally for Windows 32-bit platforms) |
| allowNAs_if_not_legacy | used if legacy is FALSE, default FALSE; introduced to handle use of NAs as object separators in oce |
| coordOp | default NULL, for PROJ >= 6 used to pass through a pre-defined coordinate operation |
| verbose | default FALSE, for PROJ >=6 used to show the coordinate operation used |
| use_aoi | With PROJ >= 6, use the area of interest defined as the range of |
Details
Full details of projection arguments available from website below, and examples in file "epsg" in the data directory installed with PROJ.4.
Note that from PROJ.4 4.9.3, the definition of UTM is changed from TMERC to ETMERC; see example.
Value
A two column matrix with projected coordinates.
References
Author
Barry Rowlingson, Roger Bivand Roger.Bivand@nhh.no
Note
The locations of Hawaii and Alaska in the data source are (putting it mildly) arbitrary, please avoid airlines using these positions.
See also
Examples
data(state) res <- project(cbind(state.center$x, state.center$y), "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100 +ellps=WGS84") res1 <- project(res, "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100 +ellps=WGS84", inv=TRUE) summary(res1 - cbind(state.center$x, state.center$y))#> V1 V2 #> Min. :-1.421e-14 Min. :-3.553e-14 #> 1st Qu.: 0.000e+00 1st Qu.:-1.421e-14 #> Median : 0.000e+00 Median : 0.000e+00 #> Mean :-1.421e-15 Mean :-3.553e-15 #> 3rd Qu.: 0.000e+00 3rd Qu.: 2.665e-15 #> Max. : 0.000e+00 Max. : 2.842e-14broke_proj <- FALSE pv <- .Call("PROJ4VersionInfo", PACKAGE="rgdal")[[2]] # https://github.com/OSGeo/PROJ/issues/1525 if (pv >= 600 && pv < 620) broke_proj <- TRUE if (!broke_proj) { crds <- matrix(data=c(9.05, 48.52), ncol=2) a <- project(crds, paste("+proj=ob_tran +o_proj=longlat", "+o_lon_p=-162 +o_lat_p=39.25 +lon_0=180 +ellps=sphere +no_defs"), use_ob_tran=TRUE) a #should be (-5.917698, -1.87195) project(a, paste("+proj=ob_tran +o_proj=longlat", "+o_lon_p=-162 +o_lat_p=39.25 +lon_0=180 +ellps=sphere +no_defs"), inv=TRUE, use_ob_tran=TRUE) #added after posting by Martin Ivanov }#> [,1] [,2] #> [1,] 9.05 48.52#> [1] "Rel. 8.1.1, September 1st, 2021, [PJ_VERSION: 811]" #> attr(,"short") #> [1] 811# Test for UTM == TMERC (<= 4.9.2) or UTM == ETMERC (> 4.9.2) nhh <- matrix(c(5.304234, 60.422311), ncol=2) nhh_utm_32N_P4 <- project(nhh, "+init=epsg:3044") nhh_tmerc_P4 <- project(nhh, paste("+proj=tmerc +k=0.9996 +lon_0=9", "+x_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs")) nhh_etmerc_P4 <- project(nhh, paste("+proj=etmerc +k=0.9996 +lon_0=9", "+x_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs")) all.equal(nhh_utm_32N_P4, nhh_tmerc_P4, tolerance=1e-9, scale=1)#> [1] TRUE#> [1] TRUE# UTM == ETMERC: PROJ4 > 4.9.2 unis <- matrix(c(15.653453, 78.222504), ncol=2) unis_utm_33N_P4 <- project(unis, "+init=epsg:3045") unis_tmerc_P4 <- project(unis, paste("+proj=tmerc +k=0.9996 +lon_0=15", "+x_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs")) unis_etmerc_P4 <- project(unis, paste("+proj=etmerc +k=0.9996 +lon_0=15", "+x_0=500000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs")) all.equal(unis_utm_33N_P4, unis_tmerc_P4, tolerance=1e-9, scale=1)#> [1] TRUE#> [1] TRUE# UTM == ETMERC: PROJ4 > 4.9.2 #pv <- attr(getPROJ4VersionInfo(), "short") #if (pv < 500) { # valgrind leakages in some cases for PROJ >= 5; many non-projection proj values added # available projections and their inverses if provided # For >=4.9.3 returns non-finite points rather than needing crash protection projs <- as.character(projInfo()$name) res <- logical(length(projs)) names(res) <- projs msgs <- character(length(projs)) names(msgs) <- projs owarn <- options("warn")$warn options(warn=2L) for (i in seq(along=res)) { iprs <- paste("+proj=", projs[i], sep="") xy <- try(project(cbind(0, 0), iprs, legacy=TRUE, use_aoi=FALSE), silent=TRUE) if (inherits(xy, "try-error")) { res[i] <- NA msgs[i] <- paste("fwd:", strsplit(xy, "\n")[[1]][2]) } else if(any(abs(xy) > 1e+08)) { res[i] <- NA msgs[i] <- paste("fwd: huge value") } else { out <- try(project(xy, iprs, inv=TRUE, legacy=TRUE, use_aoi=FALSE), silent=TRUE) if (inherits(out, "try-error")) { res[i] <- NA msgs[i] <- paste("inv:", strsplit(out, "\n")[[1]][2]) } else { res[i] <- isTRUE(all.equal(cbind(0,0), out)) } } } options(warn=owarn) df <- data.frame(res=unname(res), msgs=unname(msgs), row.names=names(res)) # projection and inverse projection failures # fwd: missing parameters # inv: mostly inverse not defined df[is.na(df$res),]#> res #> adams_hemi NA #> adams_ws1 NA #> aea NA #> airy NA #> alsk NA #> apian NA #> august NA #> axisswap NA #> bacon NA #> bertin1953 NA #> boggs NA #> bonne NA #> ccon NA #> chamb NA #> defmodel NA #> deformation NA #> denoy NA #> eqdc NA #> euler NA #> geoc NA #> geos NA #> gins8 NA #> gn_sinu NA #> gs50 NA #> guyou NA #> helmert NA #> hgridshift NA #> horner NA #> imw_p NA #> isea NA #> labrd NA #> larr NA #> lask NA #> lcc NA #> lcca NA #> lsat NA #> misrsom NA #> molobadekas NA #> molodensky NA #> murd1 NA #> murd2 NA #> murd3 NA #> nicol NA #> nsper NA #> nzmg NA #> ob_tran NA #> oea NA #> omerc NA #> ortel NA #> pconic NA #> peirce_q NA #> pipeline NA #> rpoly NA #> sch NA #> tcc NA #> tinshift NA #> tissot NA #> topocentric NA #> tpeqd NA #> tpers NA #> unitconvert NA #> urm5 NA #> urmfps NA #> utm NA #> vandg2 NA #> vandg3 NA #> vandg4 NA #> vitk1 NA #> vgridshift NA #> wag7 NA #> xyzgridshift NA #> msgs #> adams_hemi inv: malformed pipeline found #> adams_ws1 inv: malformed pipeline found #> aea fwd: target crs creation failed: Invalid value for an argument #> airy inv: malformed pipeline found #> alsk fwd: huge value #> apian inv: malformed pipeline found #> august inv: malformed pipeline found #> axisswap fwd: target crs creation failed: Mutually exclusive arguments #> bacon inv: malformed pipeline found #> bertin1953 inv: malformed pipeline found #> boggs inv: malformed pipeline found #> bonne fwd: target crs creation failed: Invalid value for an argument #> ccon fwd: target crs creation failed: Invalid value for an argument #> chamb fwd: target crs creation failed: Invalid value for an argument #> defmodel fwd: target crs creation failed: Missing argument #> deformation fwd: target crs creation failed: Missing argument #> denoy inv: malformed pipeline found #> eqdc fwd: target crs creation failed: Invalid value for an argument #> euler fwd: target crs creation failed: Invalid value for an argument #> geoc fwd: source crs creation failed: Unknown error (code 4096) #> geos fwd: target crs creation failed: Invalid value for an argument #> gins8 inv: malformed pipeline found #> gn_sinu fwd: target crs creation failed: Missing argument #> gs50 fwd: huge value #> guyou inv: malformed pipeline found #> helmert fwd: source crs creation failed: Unknown error (code 4096) #> hgridshift fwd: target crs creation failed: Missing argument #> horner fwd: target crs creation failed: Missing argument #> imw_p fwd: target crs creation failed: Invalid value for an argument #> isea inv: malformed pipeline found #> labrd fwd: target crs creation failed: Invalid value for an argument #> larr inv: malformed pipeline found #> lask inv: malformed pipeline found #> lcc fwd: target crs creation failed: Invalid value for an argument #> lcca fwd: target crs creation failed: Invalid value for an argument #> lsat fwd: target crs creation failed: Invalid value for an argument #> misrsom fwd: target crs creation failed: Invalid value for an argument #> molobadekas fwd: target crs creation failed: Missing argument #> molodensky fwd: target crs creation failed: Missing argument #> murd1 fwd: target crs creation failed: Invalid value for an argument #> murd2 fwd: target crs creation failed: Invalid value for an argument #> murd3 fwd: target crs creation failed: Invalid value for an argument #> nicol inv: malformed pipeline found #> nsper fwd: target crs creation failed: Invalid value for an argument #> nzmg fwd: huge value #> ob_tran fwd: target crs creation failed: Missing argument #> oea fwd: target crs creation failed: Invalid value for an argument #> omerc fwd: target crs creation failed: Invalid value for an argument #> ortel inv: malformed pipeline found #> pconic fwd: target crs creation failed: Invalid value for an argument #> peirce_q inv: malformed pipeline found #> pipeline fwd: target crs creation failed: Invalid PROJ string syntax #> rpoly inv: malformed pipeline found #> sch fwd: target crs creation failed: Missing argument #> tcc inv: malformed pipeline found #> tinshift fwd: target crs creation failed: Missing argument #> tissot fwd: target crs creation failed: Invalid value for an argument #> topocentric fwd: target crs creation failed: Missing argument #> tpeqd fwd: target crs creation failed: Invalid value for an argument #> tpers fwd: target crs creation failed: Invalid value for an argument #> unitconvert fwd: source crs creation failed: Unknown error (code 4096) #> urm5 fwd: target crs creation failed: Missing argument #> urmfps fwd: target crs creation failed: Missing argument #> utm fwd: target crs creation failed: Unknown error (code 4096) #> vandg2 inv: malformed pipeline found #> vandg3 inv: malformed pipeline found #> vandg4 inv: malformed pipeline found #> vitk1 fwd: target crs creation failed: Invalid value for an argument #> vgridshift fwd: target crs creation failed: Missing argument #> wag7 inv: malformed pipeline found #> xyzgridshift fwd: target crs creation failed: Missing argument# inverse not equal to input # (see http://lists.maptools.org/pipermail/proj/2011-November/006015.html) df[!is.na(df$res) & !df$res,]#> res msgs #> gs48 FALSE #> lee_os FALSE#> [1] "adams_ws2" "aeqd" "affine" "aitoff" "bipc" #> [6] "calcofi" "cart" "cass" "cc" "cea" #> [11] "collg" "col_urban" "comill" "crast" "eck1" #> [16] "eck2" "eck3" "eck4" "eck5" "eck6" #> [21] "eqearth" "eqc" "etmerc" "fahey" "fouc" #> [26] "fouc_s" "gall" "geogoffset" "gnom" "goode" #> [31] "hammer" "hatano" "healpix" "rhealpix" "igh" #> [36] "igh_o" "kav5" "kav7" "krovak" "laea" #> [41] "lagrng" "lonlat" "latlon" "leac" "loxim" #> [46] "mbt_s" "mbt_fps" "mbtfpp" "mbtfpq" "mbtfps" #> [51] "merc" "mil_os" "mill" "moll" "natearth" #> [56] "natearth2" "nell" "nell_h" "noop" "ocea" #> [61] "ortho" "patterson" "poly" "pop" "push" #> [66] "putp1" "putp2" "putp3" "putp3p" "putp4p" #> [71] "putp5" "putp5p" "putp6" "putp6p" "qua_aut" #> [76] "qsc" "robin" "rouss" "set" "sinu" #> [81] "somerc" "stere" "sterea" "gstmerc" "tcea" #> [86] "times" "tmerc" "tobmerc" "ups" "vandg" #> [91] "wag1" "wag2" "wag3" "wag4" "wag5" #> [96] "wag6" "webmerc" "weren" "wink1" "wink2" #> [101] "wintri"#} # oce data representation with NAs ll <- structure(c(12.1823368669203, 11.9149630062421, 12.3186076188739, 12.6207597184845, 12.9955172054652, 12.6316117692658, 12.4680041846297, 12.4366882666609, NA, NA, -5.78993051516384, -5.03798674888479, -4.60623015708619, -4.43802336997614, -4.78110320396188, -4.99127125409291, -5.24836150474498, -5.68430388755925, NA, NA), .Dim = c(10L, 2L), .Dimnames = list(NULL, c("longitude", "latitude"))) try(xy0 <- project(ll, "+proj=moll", legacy=TRUE)) if (!PROJis6ormore()) { # legacy=TRUE PROJ >= 6 try(xy1 <- project(ll, "+proj=moll", legacy=FALSE, allowNAs_if_not_legacy=FALSE)) try(xy2 <- project(ll, "+proj=moll", legacy=FALSE, allowNAs_if_not_legacy=TRUE)) if (exists("xy0")) all.equal(xy0, xy2) } if (!exists("xy0")) xy0 <- structure(c(1217100.8468177, 1191302.229156, 1232143.28841193, 1262546.27733232, 1299648.82357849, 1263011.18154638, 1246343.17808186, 1242654.33986052, NA, NA, -715428.207551599, -622613.577983058, -569301.605757784, -548528.530156422, -590895.949857199, -616845.926397351, -648585.161643274, -702393.1160979, NA, NA), .Dim = c(10L, 2L), .Dimnames = list(NULL, c("longitude", "latitude"))) try(ll0 <- project(xy0, "+proj=moll", inv=TRUE, legacy=TRUE)) if (!PROJis6ormore()) { # legacy=TRUE PROJ >= 6 try(ll1 <- project(xy0, "+proj=moll", inv=TRUE, legacy=FALSE, allowNAs_if_not_legacy=FALSE)) try(ll2 <- project(xy0, "+proj=moll", inv=TRUE, legacy=FALSE, allowNAs_if_not_legacy=TRUE)) if (exists("ll0")) all.equal(ll0, ll2) } if (exists("ll0")) all.equal(ll0, ll)#> [1] TRUE
