add focus:scale to /search requests with just viewport.*, calculated from bounding box diagonal, minimum of 1

query/search.js

@@ -1,7 +1,8 @@
 var peliasQuery = require('pelias-query'),
     defaults = require('./defaults'),
     textParser = require('./text_parser'),
-    check = require('check-types');
+    check = require('check-types'),
+    geolib = require('geolib');
 
 //------------------------------
 // general-purpose search query
@@ -74,10 +75,10 @@ function generateQuery( clean ){
       check.number(clean['focus.viewport.min_lon']) &&
       check.number(clean['focus.viewport.max_lon']) ) {
     // calculate the centroid from the viewport box
-    // simply set focus:point:lat/lon, until we improve this with a radius
     vs.set({
       'focus:point:lat': clean['focus.viewport.min_lat'] + ( clean['focus.viewport.max_lat'] - clean['focus.viewport.min_lat'] ) / 2,
-      'focus:point:lon': clean['focus.viewport.min_lon'] + ( clean['focus.viewport.max_lon'] - clean['focus.viewport.min_lon'] ) / 2
+      'focus:point:lon': clean['focus.viewport.min_lon'] + ( clean['focus.viewport.max_lon'] - clean['focus.viewport.min_lon'] ) / 2,
+      'focus:scale': calculateDiagonalDistance(clean) + 'km'
     });
   }
 
@@ -125,4 +126,20 @@ function generateQuery( clean ){
   return query.render( vs );
 }
 
+// return diagonal distance in km, with min=1
+function calculateDiagonalDistance(clean) {
+  var diagonalDistance = geolib.getDistance(
+    { latitude: clean['focus.viewport.min_lat'], longitude: clean['focus.viewport.min_lon'] },
+    { latitude: clean['focus.viewport.max_lat'], longitude: clean['focus.viewport.max_lon'] },
+    1000
+  ) / 1000;
+
+  if (diagonalDistance === 0) {
+    return 1;
+  }
+
+  return diagonalDistance;
+
+}
+
 module.exports = generateQuery;

test/unit/fixture/search_linguistic_viewport.js

@@ -44,7 +44,7 @@ module.exports = {
                       'lon': -82.50622
                     },
                     'offset': '1km',
-                    'scale': '50km',
+                    'scale': '994km',
                     'decay': 0.5
                   }
                 }

test/unit/fixture/search_linguistic_viewport_min_diagonal.js

@@ -0,0 +1,105 @@
+
+module.exports = {
+  'query': {
+    'filtered': {
+      'query': {
+        'bool': {
+          'must': [{
+            'match': {
+              'name.default': {
+                'query': 'test',
+                'boost': 1,
+                'analyzer': 'peliasOneEdgeGram'
+              }
+            }
+          }],
+          'should': [{
+            'match': {
+              'phrase.default': {
+                'query': 'test',
+                'analyzer': 'peliasPhrase',
+                'type': 'phrase',
+                'boost': 1,
+                'slop': 2
+              }
+            }
+          }, {
+            'function_score': {
+              'query': {
+                'match': {
+                  'phrase.default': {
+                    'analyzer': 'peliasPhrase',
+                    'type': 'phrase',
+                    'boost': 1,
+                    'slop': 2,
+                    'query': 'test'
+                  }
+                }
+              },
+              'functions': [{
+                'linear': {
+                  'center_point': {
+                    'origin': {
+                      'lat': 28.49136,
+                      'lon': -87.50623
+                    },
+                    'offset': '1km',
+                    'scale': '1km',
+                    'decay': 0.5
+                  }
+                }
+              }],
+              'score_mode': 'avg',
+              'boost_mode': 'replace'
+            }
+          },
+          {
+            'function_score': {
+              'query': {
+                'filtered': {
+                  'filter': {
+                    'exists': {
+                      'field': 'popularity'
+                    }
+                  }
+                }
+              },
+              'max_boost': 2,
+              'score_mode': 'first',
+              'boost_mode': 'replace',
+              'filter': {
+                'or': [
+                  {
+                    'type': {
+                      'value': 'admin0'
+                    }
+                  },
+                  {
+                    'type': {
+                      'value': 'admin1'
+                    }
+                  },
+                  {
+                    'type': {
+                      'value': 'admin2'
+                    }
+                  }
+                ]
+              },
+              'functions': [{
+                'field_value_factor': {
+                  'modifier': 'sqrt',
+                  'field': 'popularity'
+                },
+                'weight': 1
+              }]
+            }
+          }]
+        }
+      }
+    }
+  },
+  'sort': [ '_sort' ],
+  'size': 10,
+  'track_scores': true
+};

test/unit/query/search.js

@@ -97,6 +97,24 @@ module.exports.tests.query = function(test, common) {
     t.end();
   });
 
+  test('search with viewport diagonal < 1km should set scale to 1km', function(t) {
+    var query = generate({
+      text: 'test', size: 10,
+      'focus.viewport.min_lat': 28.49135,
+      'focus.viewport.max_lat': 28.49137,
+      'focus.viewport.min_lon': -87.50622,
+      'focus.viewport.max_lon': -87.50624,
+      layers: ['test']
+    });
+
+    var compiled = JSON.parse( JSON.stringify( query ) );
+    var expected = require('../fixture/search_linguistic_viewport_min_diagonal');
+    expected.sort = sort;
+
+    t.deepEqual(compiled, expected, 'valid search query');
+    t.end();
+  });
+
   test('search search + focus on null island', function(t) {
     var query = generate({
       text: 'test', size: 10,