Created function to convert e,n to lat,lon and optionally truncate results

1 files changed, 64 insertions, 6 deletions

diff --git a/perllib/Utils.pm b/perllib/Utils.pm
index 24f4a6f94..d54e081c8 100644
--- a/perllib/Utils.pm
+++ b/perllib/Utils.pm
@@ -13,18 +13,76 @@ package Utils;
 
 use strict;
 use mySociety::DBHandle qw(dbh);
+use mySociety::GeoUtil;
 
 sub workaround_pg_bytea {
-    my ($st, $img_idx, @elements) = @_;
+    my ( $st, $img_idx, @elements ) = @_;
     my $s = dbh()->prepare($st);
-    for (my $i=1; $i<=@elements; $i++) {
-        if ($i == $img_idx) {
-            $s->bind_param($i, $elements[$i-1], { pg_type => DBD::Pg::PG_BYTEA });
-        } else {
-            $s->bind_param($i, $elements[$i-1]);
+    for ( my $i = 1 ; $i <= @elements ; $i++ ) {
+        if ( $i == $img_idx ) {
+            $s->bind_param(
+                $i,
+                $elements[ $i - 1 ],
+                { pg_type => DBD::Pg::PG_BYTEA }
+            );
+        }
+        else {
+            $s->bind_param( $i, $elements[ $i - 1 ] );
         }
     }
     $s->execute();
 }
 
+=head2 convert_en_to_latlon
+
+    ( $latitude, $longitude ) = Utils::convert_en_to_latlon( $easting, $northing );
+
+Takes the easting and northing and returns latitude and longitude.
+
+=cut
+
+sub convert_en_to_latlon {
+    my ( $easting, $northing ) = @_;
+
+    my ( $latitude, $longitude ) =
+
+      # map { truncate_coordinate($_) }
+      mySociety::GeoUtil::national_grid_to_wgs84( $easting, $northing, 'G' );
+
+    return ( $latitude, $longitude );
+}
+
+=head2 convert_en_to_latlon_truncated
+
+    ( $lat, $lon ) = Utils::convert_en_to_latlon( $easting, $northing );
+
+Takes the easting and northing and returns latitude and longitude (truncated
+using C<Utils::truncate_coordinate>).
+
+=cut
+
+sub convert_en_to_latlon_truncated {
+    my ( $easting, $northing ) = @_;
+
+    return
+      map { truncate_coordinate($_) }
+      convert_en_to_latlon( $easting, $northing );
+}
+
+=head2 truncate_coordinate
+
+    $short = Utils::truncate_coordinate( $long );
+
+Given a long coordinate returns a shorter one - rounded to 6 decimal places -
+which is < 1m at the equator.
+
+=cut
+
+sub truncate_coordinate {
+    my $in = shift;
+    my $out = sprintf( '%0.6f', $in );
+    $out =~ s{\.?0+\z}{} if $out =~ m{\.};
+    return $out;
+}
+
 1;