Google Earth Engine compute point-polygon distances

Question

I am trying to compute distances from points stored in a fusion table to the nearest political border (also from a Table) in Google Earth Engine.

I need to compute distances between points. I would need the country name at the nearest border (it is stored under the variable 'name' in the border-table).

Please find the code below,

var fg_points = ee.FeatureCollection('ft:1DVI9dvjC00QhP-
hZgO3wQeH45RO2FDtdVcvF0fZq');
var borders = ee.FeatureCollection('USDOS/LSIB/2013');
Map.setCenter(74.582748, 42.882004, 8);     

// Define a spatial filter with max distance to points is 500.
var spatialFilter = ee.Filter.withinDistance({
distance: 500000,
leftField: '.geo',
rightField: '.geo',
maxError: 10
})

//join the points to borders
var joined = ee.Join.saveAll({
matchesKey: 'neighbors', 
measureKey: 'distance',
ordering: 'distance'
}).apply({
primary: fg_points, 
secondary: borders, 
condition: spatialFilter
});

// Get rid of points w/o neighbors.
var hasNearest = joined.map(function(f) {
var neighsSize = ee.List(f.get('neighbors')).size();
return f.set('neighsSize', neighsSize);
}).filter(ee.Filter.gt('neighsSize', 1));
Map.addLayer(hasNearest, {color: 'red'}, 'hasNearest');

// Get distance to nearest point.
var withNearestDist = hasNearest.map(function(f) {
var nearestDist = ee.Feature(ee.List(f.get('neighbors')).get(1))
.get('distance');
return f.set('nearestDist', nearestDist);
});

Export.table.toDrive(hasNearest,
"Distance",
"Distance",
"Distance");

Answer 1

Unless I'm misunderstanding your objectives, your code works just fine, you're just not exporting the collection with the distances. Export the withNearestDist collection instead of the hasNearest collection: Export.table.toDrive(withNearestDist).

If you want the name of the nearest country, you can add it in the map call where you set the nearestDist property.

Answer 2

First, you need to calculate the Point you want such as Define a Point object and Define other inputs then you get the point. distance(...) =............... this number is instead of distance 500000. Code for Point Distance below:

// Define a Point object.
var point = ee.Geometry.Point(101.88041615585351,21.15823665733664);

// Define other inputs.
var inputGeom = ee.Geometry.Point(107.26371693710351,14.915008918230788);

// Apply the distance method to the Point object.
var pointDistance = point.distance({'right': inputGeom, 'maxError': 1});

// Print the result to the console.
print('point.distance(...) =', pointDistance);

// Display relevant geometries on the map.
Map.centerObject(table, 8);
Map.addLayer(point,
             {'color': 'black'},
             'Geometry [black]: point');
Map.addLayer(inputGeom,
             {'color': 'blue'},
             'Parameter [blue]: inputGeom');