diff --git a/lib/torque/leaflet/leaflet_tileloader_mixin.js b/lib/torque/leaflet/leaflet_tileloader_mixin.js
index 1e72a48..1284099 100644
--- a/lib/torque/leaflet/leaflet_tileloader_mixin.js
+++ b/lib/torque/leaflet/leaflet_tileloader_mixin.js
@@ -17,6 +17,31 @@ L.Mixin.TileLoader = {
     this._removeTiles();
   },
 
+  visibleTiles: function() {
+    if (!this._map) { return []; }
+    var j, i, point, tiles = [];
+    var bounds = this._map.getPixelBounds(),
+        zoom = this._map.getZoom(),
+        tileSize = this.options.tileSize;
+
+    var nwTilePoint = new L.Point(
+            Math.floor(bounds.min.x / tileSize),
+            Math.floor(bounds.min.y / tileSize)),
+
+        seTilePoint = new L.Point(
+            Math.floor(bounds.max.x / tileSize),
+            Math.floor(bounds.max.y / tileSize)),
+
+        tileBounds = new L.Bounds(nwTilePoint, seTilePoint);
+
+    for (j = tileBounds.min.y; j <= tileBounds.max.y; j++) {
+        for (i = tileBounds.min.x; i <= tileBounds.max.x; i++) {
+            tiles.push({ x: i, y: j, z: zoom });
+        }
+    }
+    return tiles;
+  },
+
   _updateTiles: function () {
 
       if (!this._map) { return; }
diff --git a/lib/torque/leaflet/torque.js b/lib/torque/leaflet/torque.js
index 9962b98..f806dcc 100644
--- a/lib/torque/leaflet/torque.js
+++ b/lib/torque/leaflet/torque.js
@@ -212,24 +212,9 @@ L.TorqueLayer = L.CanvasLayer.extend({
     }
   },
 
-  getHistogramForVisibleRegion: function(varName, callback){
-    var tiles= []
-    for(var key in this._tiles){
-      if (this._tiles[key]) {
-        tiles.push(this._tiles[key].coord)
-      }
-    }
-    var tilesFilter = this.provider._generateBoundsQuery(tiles);
-
-    this.provider.tablesForFilter(tilesFilter, function(tables) {
-      // select the table with less than 100k records
-      var table = tables.filter(function(f) {
-        return f.nrows < 50000;
-      })
-      table = table.length ? table[0].table_name: this.options.overview_tables[this.options.overview_tables.length - 1]
-      this.provider.getHistogramForTiles(varName, tiles, table, callback)
-    }.bind(this));
-
+  getHistogramForVisibleRegion: function(varName, start, end, bins, callback){
+    var tiles = this.visibleTiles();
+    this.provider.getHistogramForTiles(varName, start, end, bins, tiles, callback);
   },
 
   getHistogram:function(variable,callback,noBins){
diff --git a/lib/torque/provider/filterableJson.js b/lib/torque/provider/filterableJson.js
index e6ca0dd..dd911a5 100644
--- a/lib/torque/provider/filterableJson.js
+++ b/lib/torque/provider/filterableJson.js
@@ -439,7 +439,6 @@ var Profiler = require('../profiler');
 
       sql = sql.join(' ')
 
-
       var query = format(sql,{
         x: tile.x,
         y: tile.y,
@@ -453,11 +452,11 @@ var Profiler = require('../profiler');
       })
 
       this.sql(query,function(data){
-        if(data) {
+        if (data) {
           var rows = JSON.parse(data.responseText).rows;
           callback(rows)
         }
-        else{
+        else {
           callback(null)
         }
       })
@@ -618,18 +617,48 @@ var Profiler = require('../profiler');
       }).join(" or ")
     },
 
-    getHistogramForTiles: function(varName, tiles, table, callback){
+    getHistogramForTiles: function(varName, start, end, bins, tiles, callback) {
+      var tilesFilter = this._generateBoundsQuery(tiles);
+      this.tablesForFilter(tilesFilter, function(tables) {
+        // select the table with less than 100k records
+        var table = tables.filter(function(f) {
+          return f.nrows < 50000;
+        })
+        table = table.length ? table[0].table_name: this.options.overview_tables[this.options.overview_tables.length - 1]
+        this._getHistogramForTiles(varName, start, end, bins, tiles, table, callback)
+      }.bind(this));
+    },
+
+    _getHistogramForTiles: function(varName, start, end, bins, tiles, table, callback){
+
 
       var sql = [
       'with source as (',
-         'select {varName} from {table} where ({bounds}) {filters}',
-      '),',
-      'width as (',
-         'select min({varName}) as min,',
-                 'max({varName}) as max,',
-                '{bins} as buckets',
-                'from source',
-      '),',
+         'select {varName} from {table} {tiles} where {bounds} {filters}',
+      '),'
+      ]
+      if (start !== undefined) {
+        sql = sql.concat([
+          'width as (',
+             'select {start} as min,',
+                    '{end} as max,',
+                    '{bins} as buckets',
+          '),'
+        ])
+      } else {
+        start = start === undefined ? 'min(' + varName + ')': start;
+        end   = end   === undefined ? 'max(' + varName + ')': end;
+        bins  = bins  === undefined ? 100: bins;
+        sql = sql.concat([
+          'width as (',
+             'select {start} as min,',
+                    '{end} as max,',
+                    '{bins} as buckets',
+                    'from source',
+          '),'
+        ])
+      }
+      sql = sql.concat([
       '_bw as ( select (max - min)/buckets as bw from width ),',
       'histogram as (',
         'select width_bucket({varName}, min, max, buckets) as bucket,',
@@ -640,16 +669,35 @@ var Profiler = require('../profiler');
         'order by bucket',
       ')',
       'select bucket*bw as start, (bucket+1)*bw as end, bucket as bin, lower(range) as min, upper(range) as max, freq from histogram, _bw;'
-      ]
+      ]);
 
       var filters = this._generateFiltersSQL(false, [varName]) ?  " and "+ this._generateFiltersSQL(false, [varName]) : ""
 
+      var tiles_query = tiles.map(function (t, i) {
+        return "xyz2range(" + t.x + "," + t.y + "," + t.z + ") q" + i;
+      }).join(',')
+
+      if (tiles_query) {
+        tiles_query = "," + tiles_query
+      }
+
+      var bounds = tiles.map(function(t, i) {
+        return format("(quadkey between q{i}.min and q{i}.max)", { i: i })
+      }).join('or')
+
+      if (bounds) {
+        bounds = '(' + bounds + ')';
+      }
+
       var query = format(sql.join('\n'), {
         varName: varName,
         table: table,
+        tiles: tiles_query,
         filters: filters,
-        bounds: this._generateBoundsQuery(tiles),
-        bins: 20
+        bounds: bounds,
+        bins: bins,
+        start: start,
+        end: end
       });
 
       var self = this;
@@ -663,6 +711,34 @@ var Profiler = require('../profiler');
       });
     },
 
+    getCatHistogramForTiles: function(varName, tiles, table, callback){
+
+      var sql = [
+        'select {varName}, count(1) from {table} where ({bounds}) {filters} group by 1 order by 2 desc limit {num_cats}',
+      ]
+
+      var filters = this._generateFiltersSQL(false, [varName]) ?  " and "+ this._generateFiltersSQL(false, [varName]) : ""
+
+      var query = format(sql.join('\n'), {
+        varName: varName,
+        table: table,
+        filters: filters,
+        bounds: this._generateBoundsQuery(tiles),
+        num_cats: 20
+      });
+
+      var self = this;
+      this.sql(query, function (data) {
+        if (data) {
+          var rows = JSON.parse(data.responseText).rows;
+          callback(rows);
+        } else {
+          callback(null);
+        }
+      });
+    },
+
+
     tablesForFilter: function(filter, callback) {
       var filters = this._generateFiltersSQL()
       if (filters) {