mirror of https://github.com/pelias/api.git
Peter Johnson @insertcoffee
10 years ago
4 changed files with 62 additions and 137 deletions
@ -1,65 +0,0 @@
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function deg2rad(degrees) { |
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return Math.PI*degrees/180; |
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} |
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function rad2deg(radians) { |
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return 180.0*radians/Math.PI; |
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} |
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// Semi-axes of WGS-84 geoidal reference
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var WGS84_a = 6378137.0; // Major semiaxis [m]
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var WGS84_b = 6356752.3; // Minor semiaxis [m]
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// Earth radius at a given latitude, according to the WGS-84 ellipsoid [m]
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function WGS84EarthRadius(lat){ |
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// http://en.wikipedia.org/wiki/Earth_radius
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var An = WGS84_a*WGS84_a * Math.cos(lat); |
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var Bn = WGS84_b*WGS84_b * Math.sin(lat); |
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var Ad = WGS84_a * Math.cos(lat); |
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var Bd = WGS84_b * Math.sin(lat); |
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return Math.sqrt( (An*An + Bn*Bn)/(Ad*Ad + Bd*Bd) ); |
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} |
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// Bounding box surrounding the point at given coordinates,
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// assuming local approximation of Earth surface as a sphere
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// of radius given by WGS84
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function boundingBox(latitudeInDegrees, longitudeInDegrees, halfSideInKm) { |
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var lat = deg2rad(latitudeInDegrees); |
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var lon = deg2rad(longitudeInDegrees); |
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var halfSide = 1000*halfSideInKm; |
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// Radius of Earth at given latitude
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var radius = WGS84EarthRadius(lat); |
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// Radius of the parallel at given latitude
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var pradius = radius*Math.cos(lat); |
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var latMin = lat - halfSide/radius; |
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var latMax = lat + halfSide/radius; |
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var lonMin = lon - halfSide/pradius; |
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var lonMax = lon + halfSide/pradius; |
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return { |
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'bottom_left': { |
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'lat': rad2deg(latMin),
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'lon': rad2deg(lonMin) |
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}, |
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'top_right': { |
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'lat': rad2deg(latMax),
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'lon': rad2deg(lonMax)
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}
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}; |
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} |
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// middleware
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function middleware(req, res, next){ |
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req.clean = req.clean || {}; |
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// ideally, bbox should be part of the req (and not to be calculated)
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// TBD
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req.clean.bbox = boundingBox(req.query.lat, req.query.lon, 20); |
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next(); |
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} |
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// middleware
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module.exports.middleware = middleware |
@ -1,46 +1,26 @@
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var logger = require('../src/logger'); |
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// Build pelias search query
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var logger = require('../src/logger'), |
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queries = require('geopipes-elasticsearch-backend').queries; |
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function generate( params ){ |
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var cmd = { |
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"query":{ |
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"query_string" : { |
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"query": params.input, |
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"fields": ['name.default'], |
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"default_operator": 'OR' |
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} |
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}, |
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"filter": { |
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"geo_bounding_box": { |
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"center_point": { |
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"bottom_left": { |
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"lat": params.bbox.bottom_left.lat, |
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"lon": params.bbox.bottom_left.lon |
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}, |
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"top_right": { |
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"lat": params.bbox.top_right.lat, |
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"lon": params.bbox.top_right.lon |
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} |
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} |
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} |
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}, |
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"sort" : [{ |
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"_geo_distance" : { |
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"center_point" : { |
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"lat": params.lat,
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"lon": params.lon
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}, |
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"order": 'asc', |
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"unit": 'km' |
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} |
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}], |
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"size": params.size |
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var centroid = { |
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lat: params.lat, |
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lon: params.lon |
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}; |
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// logger.log( 'cmd', JSON.stringify( cmd, null, 2 ) );
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return cmd; |
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var query = queries.distance( centroid, { size: params.size } ); |
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// add search condition to distance query
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query.query.filtered.query = { |
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query_string : { |
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query: params.input, |
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fields: ['name.default'], |
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default_operator: 'OR' |
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} |
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}; |
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return query; |
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} |
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module.exports = generate; |
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