Analyze a cloud query to get an object with the nearest GeoPoint
I'm having trouble writing a Parse request to get a Parse object with a GeoPoint, which is CLOSEST for an injected GeoPoint. Currently the code seems to be returning the last object created.
code:
// check Parse for infections around passed GeoPoint
Parse.Cloud.define("InfectionCheck_BETA", function(request, response) {
var returnCount;
var geoPoint = request.params.geoPoint;
var query = new Parse.Query("InfectedArea");
query.withinMiles("centerPoint", geoPoint, 1); // check for infections within one mile
Parse.Promise.as().then(function() {
// query for count of infection in area, this is how we get severity
return query.count().then(null, function(error) {
console.log('Error getting InfectedArea. Error: ' + error);
return Parse.Promise.error(error);
});
}).then(function(count) {
if (count <= 0) {
// no infected areas, return 0
response.success(0);
}
returnCount = count;
return query.first().then(null, function(error) {
console.log('Error getting InfectedArea. Error: ' + error);
return Parse.Promise.error(error);
});
}).then(function(result) {
// we have the InfectedArea in question, return an array with both
response.success([returnCount, result]);
}, function(error) {
response.error(error);
});
});
I want the first () request to return an object with a CLOSEST GeoPoint in centerPoint
.
I tried adding query.near("centerPoint", geoPoint)
and query.limit(1)
to unsuccessfully.
I've seen an iOS PFQueries caller whereKey:nearGeoPoint:withinMiles:
that supposedly returns sorted based on the nearest GeoPoints. Is there a JavaScript equivalent that works like this?
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Will you try? If all distances are the same then Parse will not sort the precision you want.
// check Parse for infections around passed GeoPoint
Parse.Cloud.define("InfectionCheck_BETA", function(request, response) {
var geoPoint = request.params.geoPoint;
var query = new Parse.Query("InfectedArea");
query.near("centerPoint", geoPoint);
query.limit(10);
query.find({
success: function(results) {
var distances = [];
for (var i = 0; i < results.length; ++i){
distances.push(results[i].kilometersTo(geoPoint));
}
response.success(distances);
},
error: function(error) {
response.error("Error");
}
});
});
This results in the ten closest distances.
After the conversation, it seems that the reason the distances are not sorted is because Parse only sorts to within a few centimeters. The differences the user was looking at was less than that.
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