Make KML LineString follow roads - kml

Question

I am working on a KML file with two co ordinates that I use to draw line strings. It works fine when the roads are straight, but whenever the road curves the lines do not curve. Here is the KML code I use
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
<Document>
<open>1</open>
<Style id="s_ylw-pushpin_hl">
<IconStyle>
<color>ffff5500</color>
<scale>0.583333</scale>
<Icon>
<href>http://maps.google.com/mapfiles/kml/paddle/wht-blank.png</href>
</Icon>
</IconStyle>
<LabelStyle>
<color>00ffffff</color>
</LabelStyle>
<ListStyle />
<LineStyle>
<color>ff0000ff</color>
<width>3.6</width>
</LineStyle>
<PolyStyle>
<fill>0</fill>
</PolyStyle>
</Style>
<StyleMap id="m_pushpin">
<Pair>
<key>normal</key>
<styleUrl>#s_ylw-pushpin</styleUrl>
</Pair>
<Pair>
<key>highlight</key>
<styleUrl>#s_ylw-pushpin_hl</styleUrl>
</Pair>
</StyleMap>
<Style id="s_ylw-pushpin">
<IconStyle>
<color>ffff5500</color>
<scale>0.5</scale>
<Icon>
<href>http://maps.google.com/mapfiles/kml/paddle/wht-blank.png</href>
</Icon>
</IconStyle>
<LabelStyle>
<color>00ffffff</color>
</LabelStyle>
<ListStyle />
<LineStyle>
<color>ff0000ff</color>
<width>3.6</width>
</LineStyle>
<PolyStyle>
<fill>0</fill>
</PolyStyle>
</Style>
<Placemark>
<name>Test Fac 10-26-2020</name>
<description>Sidewalk</description>
<sidewalk_missing>No</sidewalk_missing>
<LineString>
<extrude>1</extrude>
<tessellate>1</tessellate>
<coordinates>-104.818968772888,39.710975093838,0 -104.810267686844,39.708465999778,0</coordinates>
</LineString>
<Style>
<LineStyle>
<color>ffff0000</color>
<width>5</width>
</LineStyle>
</Style>
</Placemark>
<Placemark>
<name>Test Fac 10-26-2020</name>
<description>Sidewalk 1</description>
<sidewalk_missing>No</sidewalk_missing>
<LineString>
<extrude>1</extrude>
<tessellate>1</tessellate>
<coordinates>-104.819033145905,39.707747919881,0 -104.814473390579,39.70400883137,0</coordinates>
</LineString>
<Style>
<LineStyle>
<color>ffff0000</color>
<width>5</width>
</LineStyle>
</Style>
</Placemark>
</Document>
</kml>
I would like the LineString to follow similar to the yellow lines on the road. I looked into Directions API, but can't figure out a better way.

Answer 1

I was able to query Google Roads API as below and parse the json response and add multi geometry to KML file with the resulting co-ordinates
string url = #"https://roads.googleapis.com/v1/snapToRoads?path=" + beginLat + "," + beginLon + "|" + endLat + "," + endLon + "&interpolate=true&key=";
System.Net.WebRequest request = System.Net.WebRequest.Create(url);
System.Net.WebResponse response = request.GetResponse();
System.IO.Stream data = response.GetResponseStream();
System.IO.StreamReader reader = new System.IO.StreamReader(data);
string responseFromServer = reader.ReadToEnd();
response.Close();
Here is the json parser code. The co-ordinates are inside the "locations" table inside the dataset.
jsonString = $"{{ \"snappedPoints\": {{{jsonString.Trim().TrimStart('{').TrimEnd('}')}}} }}";
var xd = JsonConvert.DeserializeXmlNode(jsonString);
var result = new DataSet();
result.ReadXml(new XmlNodeReader(xd), mode);
return result;
Thank you all for the help and pointing me towards the right direction.