wktproj

#!/usr/bin/env bash
PROGRAM_NAME=$(basename "$0")
EPSG_IN=$1
EPSG_OUT=$2
WKT_STRING=${3:--}

function usage {
    echo "Reproject WKT string using cs2cs from the Proj library"
    echo ""
    echo "usage: $PROGRAM_NAME <input_epsg_code> <output_epsg_code> <wkt_string|-(wkt_string on stdin)> "
    echo "    - <wkt_string>: single geometry WKT string"
    echo "    - <epsg_code>: [0-9]+"
    exit 1
}

if test "$#" -ne 3; then
    usage
fi

set -euo pipefail

function process_wkt_string() {
    local wkt_string input_epsg_code output_epsg_code
    input_epsg_code=$1
    output_epsg_code=$2
    wkt_string=$3
    geom_type=$(echo "$wkt_string" | perl -pe 's/(.*?)\(\(.*?\)\)/$1/')
    coord_string=$(echo "$wkt_string" | perl -pe 's/.*?\(\((.*?)\)\)/$1/')
    IFS=","
    result="${geom_type}(("
    for coord in $coord_string; do
        trans_coord=$(echo "$coord" | cs2cs -f "%.6f" "+init=epsg:$input_epsg_code" +to "+init=epsg:$output_epsg_code")
        trans_xy=$(echo "$trans_coord" | perl -pe 's/(.*?)\s(.*?)\s.*/$1 $2/')
        result="${result}${trans_xy},"
    done
    result="${result%?}"
    result="${result}))"
    echo "$result"
}

if [[ $WKT_STRING == "-" ]]; then
    # WKT_STRING passed on stdin
    if [ -t 0 ]; then
        # if do not allow interactive tty
        usage
    fi
    while read -r line; do
        process_wkt_string "$EPSG_IN" "$EPSG_OUT" "$line"
    done <"/dev/stdin"
else
    # BBOX passed as argument
    process_wkt_string "$EPSG_IN" "$EPSG_OUT" "$WKT_STRING"
fi