Code cleanup and comments.

modules/exif_gps/helpers/exif_gps.php

@@ -51,6 +51,7 @@ static function extract($item) {
       $record->item_id = $item->id;
       $record->latitude = $keys["Latitude"];
       $record->longitude = $keys["Longitude"];
+      // Represent N/S/E/W as postive and negative numbers
       if ($keys["Latitude Reference"] == "S") {
         $record->latitude = "-" . $record->latitude;
       }
@@ -62,6 +63,7 @@ static function extract($item) {
   }
 
   private static function _keys() {
+    // EXIF fields to extract.
     if (!isset(self::$exif_keys)) {
       self::$exif_keys = array(
         "Latitude Reference"     => array("GPS",    "Latitude Reference",       t("GPS: Latitude Reference"), ),

modules/exif_gps/helpers/exif_gps_block.php

@@ -32,6 +32,7 @@ static function get($block_id, $theme) {
 
     switch ($block_id) {
     case "exif_gps_map":
+      // Check and see if the item has exif coordinates associated with it.
       $record = ORM::factory("exif_coordinate")->where("item_id", "=", $theme->item->id)->find();
       if ($record->loaded()) {
         $block = new Block();
@@ -41,6 +42,7 @@ static function get($block_id, $theme) {
         $block->content->latitude = $record->latitude;
         $block->content->longitude = $record->longitude;
       } elseif (module::is_active("tagsmap") && module::is_active("tag")) {
+        // If there are no exif coordinates, check for tagsmap coordinates instead.
         $tagsItem = ORM::factory("tag")
           ->join("items_tags", "tags.id", "items_tags.tag_id")
           ->where("items_tags.item_id", "=", $theme->item->id)
@@ -55,7 +57,7 @@ static function get($block_id, $theme) {
               $block->content = new View("exif_gps_sidebar.html");
               $block->content->latitude = $tagsGPS->latitude;
               $block->content->longitude = $tagsGPS->longitude;
-			  break;
+              break;
             }
           }
         }

modules/exif_gps/helpers/exif_gps_task.php

@@ -38,21 +38,25 @@ static function available_tasks() {
   static function update_gps_index($task) {
     $start = microtime(true);
 
+    // Figure out the total number of photos in the database.
+    // If this is the first run, also set last_id and completed to 0.
     $total = $task->get("total");
     if (empty($total)) {
       $task->set("total", $total = count(ORM::factory("item")->where("type", "=", "photo")->find_all()));
       $task->set("last_id", 0);
       $task->set("completed", 0);
     }
-
     $last_id = $task->get("last_id");
     $completed = $task->get("completed");
 
+    // Generate an array of the next 100 photos to check.
     $all_photos = ORM::factory("item")
              ->where("id", ">", $last_id)
              ->where("type", "=", "photo")
              ->find_all(100);
 
+    // Check each photo in the array to see if it already has exif gps data associated with it.
+    //  If it doesn't, attempt to extract gps coordinates.
     foreach (ORM::factory("item")
              ->where("id", ">", $last_id)
              ->where("type", "=", "photo")