diff --git a/lib/Database/AbstractDatabase.php b/lib/Database/AbstractDatabase.php
index 2daf28b..d111c2f 100644
--- a/lib/Database/AbstractDatabase.php
+++ b/lib/Database/AbstractDatabase.php
@@ -3,6 +3,7 @@
 namespace OwntracksRecorder\Database;
 
 use \OwntracksRecorder\RecordType\AbstractRecordType;
+use \OwntracksRecorder\RecordType\Location;
 
 class AbstractDatabase
 {
@@ -96,6 +97,12 @@ class AbstractDatabase
         $min_epoch = time() - $max_age;
         $sql = 'SELECT * from locations l1 INNER JOIN (SELECT tracker_id, MAX(epoch) AS epoch FROM locations GROUP BY tracker_id) l2 ON l1.tracker_id=l2.tracker_id AND l1.epoch=l2.epoch WHERE l1.epoch >= ?';
         $result = $this->query($sql, array($min_epoch));
-        return $result;
+
+        $loclist = array();
+        foreach ($result as $entry) {
+            $loclist[] = new Location($entry);
+        }
+
+        return $loclist;
     }
 }
diff --git a/lib/RecordType/AbstractRecordType.php b/lib/RecordType/AbstractRecordType.php
index 5ccc01b..ecf6986 100755
--- a/lib/RecordType/AbstractRecordType.php
+++ b/lib/RecordType/AbstractRecordType.php
@@ -9,12 +9,20 @@ class AbstractRecordType implements \Iterator
     protected $fields = array();
     protected $data = array();
 
-    public function __construct()
+    public function __construct(array $arr = null)
     {
         // init empty record
         foreach ($this->fields as $key => $extkey) {
             $this->data[$key] = null;
         }
+
+        if (!is_null($arr)) {
+            foreach ($arr as $key => $value) {
+                if (array_key_exists($key, $this->data)) {
+                    $this->data[$key] = $value;
+                }
+            }
+        }
     }
 
     public function __isset($key)
@@ -27,6 +35,16 @@ class AbstractRecordType implements \Iterator
         return $this->data[$key];
     }
 
+    public function __set($key, $value)
+    {
+        if (array_key_exists($key, $this->fields)) {
+            if (!is_null($this->fields[$key])) {
+                settype($value, $this->fields[$key][1]);
+            }
+            $this->data[$key] = $value;
+        }
+    }
+
     public function rewind()
     {
         reset($this->data);
@@ -70,4 +88,18 @@ class AbstractRecordType implements \Iterator
             }
         }
     }
+
+    public function getJSON()
+    {
+        $result = array(
+            '_type' => $this->type,
+        );
+        foreach ($this->fields as $key => $extdata) {
+            if (is_null($extdata) || is_null($this->data[$key])) {
+                continue;
+            }
+            $result[$extdata[0]] = $this->data[$key];
+        }
+        return $result;
+    }
 }
diff --git a/lib/RecordType/Location.php b/lib/RecordType/Location.php
index 6bacd22..aa494a2 100755
--- a/lib/RecordType/Location.php
+++ b/lib/RecordType/Location.php
@@ -21,12 +21,12 @@ class Location extends AbstractRecordType
         'heading'      => array('cog', 'int'),
         'description'  => array('desc', 'string'),
         'event'        => array('event', 'string'),
-        'latitude'     => array('lat', 'float'),
-        'longitude'    => array('lon', 'float'),
+        'latitude'     => array('lat', 'float'),   // required in JSON
+        'longitude'    => array('lon', 'float'),   // required in JSON
         'radius'       => array('rad', 'int'),
         'trig'         => array('t', 'string'),
-        'tracker_id'   => array('tid', 'string'),
-        'epoch'        => array('tst', 'int'),
+        'tracker_id'   => array('tid', 'string'),   // required in JSON (http)
+        'epoch'        => array('tst', 'int'),   // required in JSON
         'vertical_accuracy' => array('vac', 'int'),
         'velocity'     => array('vel', 'int'),
         'pressure'     => array('p', 'float'),
diff --git a/record.php b/record.php
index 8f7eae0..126eea9 100644
--- a/record.php
+++ b/record.php
@@ -61,24 +61,7 @@ $response = array();
 // Build list of buddies' last locations
 $buddies = $sql->getAllLatestMarkers();
 foreach ($buddies as $buddy) {
-    $loc = array(
-        '_type' => 'location',
-        'acc' => $buddy['accuracy'],
-        'alt' => $buddy['altitude'],
-        'batt' => $buddy['battery_level'],
-        'cog' => $buddy['heading'],
-        'lat' => $buddy['latitude'],
-        'lon' => $buddy['longitude'],
-        'rad' => $buddy['radius'],
-        't' => $buddy['trig'],
-        'tid' => strval($buddy['tracker_id']),
-        'tst' => $buddy['epoch'],
-        'vac' => $buddy['vertical_accuracy'],
-        'vel' => $buddy['velocity'],
-        'p' => $buddy['pressure'],
-        'conn' => $buddy['connection'],
-    );
-    $response[] = $loc;
+    $response[] = $buddy->getJSON();
 }
 
 if (!is_null($response_msg)) {