Changeset 175 for trunk/globals/classes/srtm.php

Timestamp:

03/02/2007 02:36:10 AM (5 years ago)

Author:

Winner

Message:

"Fix: srtm class now works for all the earth. (thanx to Andre Marais)"

File:

• trunk/globals/classes/srtm.php (modified) (2 diffs)

trunk/globals/classes/srtm.php

@@ -29 +29 @@
         
         function get_elevation($lat, $lon, $round=TRUE) {
+                if ($lat < 0) {
+                        $lat_dir = 'S';
+                        $lat_adj = 1;
+                } else {
+                        $lat_dir = 'N';
+                        $lat_adj = 0;
+                }
+                if ($lon < 0) {
+                        $lon_dir = 'W';
+                        $lon_adj = 1;
+                } else {
+                        $lon_dir = 'E';
+                        $lon_adj = 0;
+                }
                 $y = $lat;
                 $x = $lon;
-        
-                $filename = $this->data_path.'N'.(integer)$lat.'E'.((integer)$lon<100?'0'.(integer)$lon:(integer)$lon).'.hgt';
-        
-                if ($lat == '' || $lon == '' || !file_exists($filename))
-                        return FALSE;
-        
+                
+                $filename = $this->data_path.$lat_dir.sprintf("%02.0f", (integer)($lat+$lat_adj)).$lon_dir.sprintf("%03.0f", (integer)($lon+$lon_adj)).'.hgt';
+                if ($lat === '' || $lon === '' || !file_exists($filename)) return FALSE;
+                
                 $file = fopen($filename, 'r');
-                $offset = ( (integer)(($x - (integer)$x) * 1200) * 2 + (1200 - (integer)(($y - (integer)$y) * 1200)) * 2402 );
+                $offset = ( (integer)(($x - (integer)$x + $lon_adj) * 1200) * 2 + (1200 - (integer)(($y - (integer)$y + $lat_adj) * 1200)) * 2402 );
                 fseek($file, $offset);
                 $h1 = bytes2int(strrev(fread($file, 2)));
@@ -54 +66 @@
                 }
         
-                $fx = ($lon - (integer)($lon * 1200) / 1200) * 1200;
-                $fy = ($lat - (integer)($lat * 1200) / 1200) * 1200;
+                $fx = ($lon - ((integer)($lon * 1200) / 1200)) * 1200;
+                $fy = ($lat - ((integer)($lat * 1200) / 1200)) * 1200;
         
                 // normalizing data