diff --git a/lib/galaxy/visualization/tracks/data_providers.py b/lib/galaxy/visualization/tracks/data_providers.py
index 65804e5edb5..d53d9c9d6a4 100644
--- a/lib/galaxy/visualization/tracks/data_providers.py
+++ b/lib/galaxy/visualization/tracks/data_providers.py
@@ -465,8 +465,8 @@ class RawBedDataProvider( BedDataProvider ):
                 feature_start = int( feature[1] )
                 feature_end = int( feature[2] )
                 if ( chrom is not None and feature_chrom != chrom ) \
-                    or ( start is not None and feature_start > int( end ) ) \
-                    or ( end is not None and feature_end < int( start ) ):
+                    or ( start is not None and feature_start > end ) \
+                    or ( end is not None and feature_end < start ):
                     continue
                 yield line
         return line_filter_iter()
@@ -599,7 +599,7 @@ class RawVcfDataProvider( VcfDataProvider ):
                     if len( alt ) > longest_alt:
                         longest_alt = len( alt )
                 variant_end = variant_start + abs( len( ref ) - longest_alt )
-                if variant_chrom != chrom or variant_start > int( end ) or variant_end < int( start ):
+                if variant_chrom != chrom or variant_start > end or variant_end < start:
                     continue
                 yield line
         return line_filter_iter()
@@ -898,16 +898,16 @@ class BBIDataProvider( TracksDataProvider ):
         return all_dat is not None
         
     def get_data( self, chrom, start, end, start_val=0, max_vals=None, **kwargs ):
-        # Bigwig has the possibility of it being a standalone bigwig file, in which case we use
-        # original_dataset, or coming from wig->bigwig conversion in which we use converted_dataset
+        # Bigwig can be a standalone bigwig file, in which case we use 
+        # original_dataset, or coming from wig->bigwig conversion in 
+        # which we use converted_dataset
         f, bbi = self._get_dataset()
        
-        # If the stats kwarg was provide, we compute overall summary data for
-        # the entire chromosome, but no reduced data -- currently only
-        # providing values used by trackster to determine the default range
+        # If the stats kwarg was provide, we compute overall summary data for the 
+        # range defined by start and end but no reduced data. This is currently 
+        # used by client to determine the default range.
         if 'stats' in kwargs:
-            # FIXME: use actual chromosome size
-            summary = bbi.summarize( chrom, 0, 214783647, 1 )
+            summary = bbi.summarize( chrom, start, end, 1 )
             f.close()
             if summary is None:
                 return None
@@ -927,9 +927,6 @@ class BBIDataProvider( TracksDataProvider ):
 
                 return dict( data=dict( min=summary.min_val[0], max=summary.max_val[0], mean=mean, sd=sd ) )
 
-        start = int(start)
-        end = int(end)
-
         # The following seems not to work very well, for example it will only return one
         # data point if the tile is 1280px wide. Not sure what the intent is.
 
@@ -943,13 +940,22 @@ class BBIDataProvider( TracksDataProvider ):
         #else:
         #    num_points = min(num_points, 500)
 
-        # For now, we'll do 1000 data points by default However, the summaries
+        # For now, we'll do 1000 data points by default. However, the summaries
         # don't seem to work when a summary pixel corresponds to less than one
         # datapoint, so we prevent that. 
-        # FIXME: need to switch over to using the full data at high levels of
-        # detail.
+
+        # FIXME: need to choose the number of points to maximize coverage of the area. 
+        # It appears that BBI calculates points using intervals of 
+        # floor( num_points / end - start ) 
+        # In some cases, this prevents sampling near the end of the interval, 
+        # especially when (a) the total interval is small ( < 20-30Kb) and (b) the 
+        # computed interval size has a large fraction, e.g. 14.7 or 35.8
         num_points = min( 1000, end - start )
 
+        # HACK to address the FIXME above; should generalize.
+        if end - start <= 2000:
+            num_points = end - start
+
         summary = bbi.summarize( chrom, start, end, num_points )
         f.close()
 
@@ -958,7 +964,6 @@ class BBIDataProvider( TracksDataProvider ):
         if summary:
             #mean = summary.sum_data / summary.valid_count
             
-
             ## Standard deviation by bin, not yet used
             ## var = summary.sum_squares - mean
             ## var /= minimum( valid_count - 1, 1 )
@@ -968,7 +973,7 @@ class BBIDataProvider( TracksDataProvider ):
             step_size = (end - start) / num_points
 
             for i in range( num_points ):
-                result.append( (pos, float_nan( summary.sum_data[i] ) ) )
+                result.append( (pos, float_nan( summary.sum_data[i] / summary.valid_count[i] ) ) )
                 pos += step_size
         
         return { 'data': result }
@@ -1078,7 +1083,6 @@ class RawGFFDataProvider( TracksDataProvider ):
         Returns an iterator that provides data in the region chrom:start-end as well as
         a file offset.
         """
-        start, end = int( start ), int( end )
         source = open( self.original_dataset.file_name )
     
         def features_in_region_iter():
diff --git a/lib/galaxy/web/controllers/tracks.py b/lib/galaxy/web/controllers/tracks.py
index 98944d14ea4..295c93533d5 100644
--- a/lib/galaxy/web/controllers/tracks.py
+++ b/lib/galaxy/web/controllers/tracks.py
@@ -267,6 +267,8 @@ class TracksController( BaseUIController, UsesVisualizationMixin, UsesHistoryDat
         msg = self.check_dataset_state( trans, dataset )
         if msg:
             return msg
+
+        low, high = int( low ), int( high )
             
         # Return data.
         data = None
@@ -402,7 +404,7 @@ class TracksController( BaseUIController, UsesVisualizationMixin, UsesHistoryDat
             data_provider = data_provider_class( converted_dataset=converted_dataset, original_dataset=dataset, dependencies=deps )
         
         # Get and return data from data_provider.
-        result = data_provider.get_data( chrom, low, high, int( start_val ), int( max_vals ), **kwargs )
+        result = data_provider.get_data( chrom, int( low ), int( high ), int( start_val ), int( max_vals ), **kwargs )
         result.update( { 'dataset_type': tracks_dataset_type, 'extra_info': extra_info } )
         return result
                 
diff --git a/static/scripts/viz/trackster.js b/static/scripts/viz/trackster.js
index afcefea9dd7..ec4fa9786a8 100644
--- a/static/scripts/viz/trackster.js
+++ b/static/scripts/viz/trackster.js
@@ -4266,9 +4266,8 @@ extend(LineTrack.prototype, Drawable.prototype, TiledTrack.prototype, {
     },
     predraw_init: function() {
         var track = this;
-        
         track.vertical_range = undefined;
-        return $.getJSON( track.data_url, {  stats: true, chrom: track.view.chrom, low: null, high: null,
+        return $.getJSON( track.data_url, {  stats: true, chrom: track.view.chrom, low: 0, high: track.view.max_high,
                                         hda_ldda: track.hda_ldda, dataset_id: track.dataset_id }, function(result) {
             track.container_div.addClass( "line-track" );
             var data = result.data;