R/spgrass.R

# Interpreted GRASS 7 interface functions
# Copyright (c) 2015 Roger S. Bivand
#

gmeta <- function(ignore.stderr = FALSE) {
        if (get.suppressEchoCmdInFuncOption()) {
            inEchoCmd <- get.echoCmdOption()
             tull <- set.echoCmdOption(FALSE)
        }
        tx <- execGRASS("g.region", flags=c("g", "3"), intern=TRUE,
            ignore.stderr=ignore.stderr)
	tx <- gsub("=", ":", tx)
	con <- textConnection(tx)
	res <- read.dcf(con)
	close(con)
	lres <- as.list(res)
	names(lres) <- colnames(res)
	lres$n <- as.double(lres$n)
	lres$s <- as.double(lres$s)
	lres$w <- as.double(lres$w)
	lres$e <- as.double(lres$e)
	lres$t <- as.double(lres$t)
	lres$b <- as.double(lres$b)
	lres$nsres <- as.double(lres$nsres)
	lres$nsres3 <- as.double(lres$nsres3)
	lres$ewres <- as.double(lres$ewres)
	lres$ewres3 <- as.double(lres$ewres3)
	lres$tbres <- as.double(lres$tbres)
	if (length(lres$rows) == 0) 
		lres$rows <- abs(as.integer((lres$n-lres$s)/lres$nsres))
	else lres$rows <- as.integer(lres$rows)
	if (length(lres$rows3) == 0) lres$rows3 <- lres$rows
	else lres$rows3 <- as.integer(lres$rows3)
	if (length(lres$cols) == 0) 
		lres$cols <- abs(as.integer((lres$e-lres$w)/lres$ewres))
	else lres$cols <- as.integer(lres$cols)
	if (length(lres$cols3) == 0) lres$cols3 <- lres$cols
	else lres$cols3 <- as.integer(lres$cols3)
	if (length(lres$depths) == 0) 
		lres$depths <- abs(as.integer((lres$t-lres$b)/lres$tbres))
	else lres$depths <- as.integer(lres$depths)
	lres$proj4 <- getLocationProj()
        gisenv <- execGRASS("g.gisenv", flags="n", intern=TRUE,
            ignore.stderr=ignore.stderr)
	gisenv <- gsub("[';]", "", gisenv)
	gisenv <- strsplit(gisenv, "=")
	glist <- as.list(sapply(gisenv, function(x) x[2]))
	names(glist) <- sapply(gisenv, function(x) x[1])
	lres <- c(glist, lres)
	class(lres) <- "gmeta"
        if (get.suppressEchoCmdInFuncOption()) {
            tull <- set.echoCmdOption(inEchoCmd)
        }
	lres
}

print.gmeta <- function(x, ...) {
    cat("gisdbase   ", x$GISDBASE, "\n")
    cat("location   ", x$LOCATION_NAME, "\n")
    cat("mapset     ", x$MAPSET, "\n")
    cat("rows       ", x$rows, "\n")
    cat("columns    ", x$cols, "\n")
    cat("north      ", x$n, "\n")
    cat("south      ", x$s, "\n")
    cat("west       ", x$w, "\n")
    cat("east       ", x$e, "\n")
    cat("nsres      ", x$nsres, "\n")
    cat("ewres      ", x$ewres, "\n")
    cat("projection ", paste(strwrap(x$proj4), collapse="\n"), "\n")
    invisible(x)
}

gmeta2grd <- function(ignore.stderr = FALSE) {
	G <- gmeta(ignore.stderr=ignore.stderr)
	cellcentre.offset <- c(G$w+(G$ewres/2), G$s+(G$nsres/2))
	cellsize <- c(G$ewres, G$nsres)
	cells.dim <- c(G$cols, G$rows)
	grd <- GridTopology(cellcentre.offset=cellcentre.offset, 
		cellsize=cellsize, cells.dim=cells.dim)
	grd
}



getLocationProj <- function(ignore.stderr = FALSE) {
# too strict assumption on g.proj Rohan Sadler 20050928
        if (get.suppressEchoCmdInFuncOption()) {
            inEchoCmd <- get.echoCmdOption()
             tull <- set.echoCmdOption(FALSE)
        }
        projstr <- execGRASS("g.proj", flags=c("j", "f"), intern=TRUE, 
            ignore.stderr=ignore.stderr)
	if (length(grep("XY location", projstr)) > 0)
		projstr <- as.character(NA)
	if (length(grep("latlong", projstr)) > 0)
		projstr <- sub("latlong", "longlat", projstr)
    	if (is.na(projstr)) uprojargs <- projstr
    	else uprojargs <- paste(unique(unlist(strsplit(projstr, " "))), 
		collapse=" ")
    	if (length(grep("= ", uprojargs)) != 0) {
		warning(paste("No spaces permitted in PROJ4",
			"argument-value pairs:", uprojargs))
		uprojargs <- as.character(NA)
	}
    	if (length(grep(" [:alnum:]", uprojargs)) != 0) {
		warning(paste("PROJ4 argument-value pairs",
			"must begin with +:", uprojargs))
		uprojargs <- as.character(NA)
	}
        if (get.suppressEchoCmdInFuncOption()) {
            tull <- set.echoCmdOption(inEchoCmd)
        }
	uprojargs
}

.g_findfile <- function(vname, type) {
    ms <- execGRASS("g.findfile", element=type, file=vname[1],
        intern=TRUE)
    tx <- gsub("=", ":", ms)
    con <- textConnection(tx)
    res <- read.dcf(con)
    close(con)
    lres <- as.list(res)
    names(lres) <- colnames(res)
    if (nchar(lres$name) == 0) 
        stop(paste(vname[1], "- file not found"))
    mapset <- gsub("'", "", lres$mapset)
    mapset    
}



.addexe <- function() {
    res <- ""
    SYS <- get("SYS", envir=.GRASS_CACHE)
    if (SYS == "msys" || SYS == "WinNat") res =".exe"
    res
}

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spgrass documentation built on May 2, 2019, 6:32 p.m.