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我正在构建一个存储位置(以及它们的坐标)的API,并且我想根据它们与用户的距离来查询它们。nodejs:计算从位置到用户的距离
在我的视图控制器,我有这样的代码:
var geolocation = angular.module('geolocation', []);
navigator.geolocation.watchPosition(render);
var lat, lon = 0;
function render(pos) {
lat = pos.coords.latitude;
lon = pos.coords.longitude;
console.log(lat +","+ lon);
}
即返回用户当前位置。 我的模式是仿照这样的:
var LocationSchema = new Schema({
locationName: {
type: String,
Required: 'Enter the name of the location.'
},
description: {
type: String,
Required: 'Enter the description of the location.'
},
geolocation: {
type: { type: String, default:"Point" },
coordinates: [Number],
},
而且在我APIcontroller,我试图做到这一点:
exports.find_all_locations_near = function(req, res) {
Location.find({
geolocation:
{
$near :
{
$geometry: { type: "Point", coordinates: [ lat, lon ] },
$minDistance: req.body.minDistance,
$maxDistance: req.body.maxDistance
}
}
}), function(err, location) {
if (err)
res.send(err);
else if (location =='')
//res.json({ message: 'No location was found.' });
console.log('No location was found.');
else
res.json(location);
};
}
我提交的最小和最大距离是这样的:
<div class="form-group">
<label>Min Distance</label> <input type="text" class="form-control text-center" ng-model="formData.minDistance"><br>
</div>
<div class="form-group">
<label>Max Distance</label> <input type="text" class="form-control text-center" ng-model="formData.maxDistance"><br>
</div>
但没有任何反应。我得到0个结果。我究竟做错了什么? 另外,我如何计算用户和位置之间的距离,并返回每一行?