// May throw: parseGeoJson may throw if geoJsonFile is not conformant.
public MkGeoMap(string geoJsonFile)
{
MkGeoMultiMap multi = new MkGeoMultiMap(geoJsonFile);
if (multi.Count != 1)
{
throw new Exception("Only support geojson with one feature (region)");
}
var keys = multi.Keys;
_name = keys.ElementAt(0);
if (multi[_name].size != 1)
{
throw new Exception("Only support geojson feature of Polygon (as opposed to MultiPolygon");
}
_polygon = multi[_name][0];
}
isInside(MkGeoMultiMap country, Vertex point, double borderMargin)
{
HashSet <string> borders = new HashSet <string>();
HashSet <string> ins = new HashSet <string>();
HashSet <string> outs = new HashSet <string>();
List <(string name, double buffer)> buffers = new List <(string name, double buffer)>();
Dictionary <string, List <(string name, double buffer)> > ret = new Dictionary <string, List <(string name, double buffer)> >();
foreach (KeyValuePair <string, MultiPolygon> kv in country)
{
string province = kv.Key;
MultiPolygon multiPoly = kv.Value;
double minBuffer = Double.PositiveInfinity;
foreach (Polygon poly in multiPoly)
{
LinearRing ring = poly.outerRing;
var res = isInside(point, ring, borderMargin);
if (res.inout == 0)
{
borders.Add(province);
}
else if (res.inout == -1)
{
ins.Add(province);
}
else if (res.inout == 1)
{
outs.Add(province);
}
if (Math.Abs(res.radius) < Math.Abs(minBuffer))
{
minBuffer = res.radius;
}
}
if (Math.Abs(minBuffer) < Double.PositiveInfinity)
{
buffers.Add((name: province, buffer: minBuffer));
}
}
HashSet <string> prov = new HashSet <string>(ins);
prov.UnionWith(borders);
foreach (string p in prov)
{
if (ins.Contains(p))
{
ret["in"] = new List <(string name, double buffer)>();
ret["in"].Add((name: p, buffer: 0.0));
}
else if (borders.Contains(p))
{
if (ret.ContainsKey("border"))
{
ret["border"].Add((name: p, buffer: 0.0));
}
else
{
ret["border"] = new List <(string name, double buffer)>();
ret["border"].Add((name: p, buffer: 0.0));
}
}
}
if (buffers.Count > 0)
{
ret["buffer"] = buffers;
}
Dictionary <string, (string name, double buffer)[]> retn = new Dictionary <string, (string name, double buffer)[]>();