diff --git a/chasemapper/config.py b/chasemapper/config.py
index 6e1f23b..f782546 100644
--- a/chasemapper/config.py
+++ b/chasemapper/config.py
@@ -53,6 +53,17 @@ default_config = {
     'bearing_weight': 1.0,
     'bearing_color': 'black',
     'bearing_custom_color': '#FF0000',
+
+    # Unit selection
+    'unitselection': 'metric',
+    'm_to_ft': 3.28084,
+    'km_to_miles' : 0.6213171,
+    'secs_to_mins' : 0.016666,
+    'ms_to_knots' : 1.94384,
+    'switch_miles_feet' : 400,
+
+
+
     }
 
 
@@ -143,12 +154,12 @@ def parse_config_file(filename):
 
         # Unit Selection
 
-	chase_config['unitselection'] = config.get('units', 'unitselection')
-	chase_config['m_to_ft'] = config.get('units', 'm_to_ft')
-	chase_config['km_to_miles'] = config.get('units', 'km_to_miles')
-	chase_config['secs_to_mins'] = config.get('units', 'secs_to_mins')
-	chase_config['ms_to_knots'] = config.get('units', 'ms_to_knots')
-	chase_config['switch_miles_feet'] = config.get('units', 'switch_miles_feet')
+	chase_config['unitselection'] = config.get('units', 'unitselection', fallback='metric')
+	chase_config['m_to_ft'] = config.get('units', 'm_to_ft', fallback = '3.28084')
+	chase_config['km_to_miles'] = config.get('units', 'km_to_miles', fallback = '0.621371')
+	chase_config['secs_to_mins'] = config.get('units', 'secs_to_mins', fallback = '0.016666')
+	chase_config['ms_to_knots'] = config.get('units', 'ms_to_knots', fallback = '1.94384')
+	chase_config['switch_miles_feet'] = config.get('units', 'switch_miles_feet', fallback = '400')
 
 	logging.info("Units:             " + chase_config['unitselection'])
 	logging.info("m_to_f:            " + chase_config['m_to_ft'])
diff --git a/horusmapper.cfg.example b/horusmapper.cfg.example
index 2b85597..f461266 100644
--- a/horusmapper.cfg.example
+++ b/horusmapper.cfg.example
@@ -211,3 +211,30 @@ bearing_color = black
 
 # Custom bearing color, in hexadecimal #RRGGBB
 bearing_custom_color = #FF0000
+
+
+
+[units]
+
+# unitselection allows choice of metric - the default or imperial1 - horizontal miles and feet for short distances, horizontal miles per hour,  vertical feet, vertical feet per minute
+
+unitselection = metric
+# unitselection = imperial1
+
+
+# Imperial conversion factors
+
+m_to_ft = 3.28084
+km_to_miles = 0.621371
+secs_to_mins = 0.016666
+ms_to_knots = 1.94384
+
+# Sensible choice of unit selection (all thresholds set in metric)
+
+# This is the threshold for switching from miles to feet, set in meters.
+switch_miles_feet = 400
+
+
+
+
+
diff --git a/static/js/tables.js b/static/js/tables.js
index 6efa107..d98767e 100644
--- a/static/js/tables.js
+++ b/static/js/tables.js
@@ -273,7 +273,7 @@ function initTablesImperial1(){
 
 function updateTelemetryTable(){
     var telem_data = [];
-    if (chase_config['unitselection'] == "imperial1") {initTablesImperial1() ; return ; } // else do everything in metric
+    if (chase_config['unitselection'] == "imperial1") {updateTelemetryTableImperial1() ; return ; } // else do everything in metric
     if (jQuery.isEmptyObject(balloon_positions)){
         telem_data = [{callsign:'None'}];
     }else{
@@ -284,7 +284,7 @@ function updateTelemetryTable(){
             // Modify some of the fields to fixed point values.
             balloon_call_data.lat = balloon_call_data.position[0].toFixed(5);
             balloon_call_data.lon = balloon_call_data.position[1].toFixed(5);
-            balloon_call_data.alt = balloon_call_data.position[2].toFixed(1) + " (" + balloon_call_data.max_alt.toFixed(0) + ")" ;
+            balloon_call_data.alt = balloon_call_data.position[2].toFixed(0) + " (" + balloon_call_data.max_alt.toFixed(0) + ")" ;
             balloon_call_data.vel_v = balloon_call_data.vel_v.toFixed(1);
 
             // Add in any extra data to the aux field.
@@ -315,7 +315,6 @@ function updateTelemetryTable(){
 
 function updateTelemetryTableImperial1(){
     var telem_data = [];
-    if (chase_config['unitselection'] == "imperial1") {initTablesImperial1() ; return ; } // else do everything in metric
     if (jQuery.isEmptyObject(balloon_positions)){
         telem_data = [{callsign:'None'}];
     }else{