Can I use GoogleMap or other GPS data in creation of the Graphs?

Question

I have following graph.

    g = Graph[{"Uppsala" -> "Marsta", "Marsta" -> "Uppsala", 
    "UpplandsVasby" -> "Sollentuna", "Sollentuna" -> "UpplandsVasby", 
    "UpplandsVasby" -> "Marsta", "Marsta" -> "UpplandsVasby", 
    "Stockholm" -> "Boo", "Boo" -> "Stockholm", 
    "Stockholm" -> "Lidingo", "Lidingo" -> "Stockholm", 
    "Stockholm" -> "Sollentuna", "Sollentuna" -> "Stockholm", 
    "Stockholm" -> "Taby", "Taby" -> "Stockholm"}, 
   VertexLabels -> "Name", ImagePadding -> 40];

coords = CityData[#, "Coordinates"] & /@ VertexList[g];

SetProperty[g, {VertexCoordinates -> Reverse[coords, 2], 
  Prolog -> {Gray, CountryData["Sweden", "Polygon"]}}]

Based on the real road connection on the GoogleMap or other GPS data ,how can I set my Edgecover the actual road connection between cities and the actual distance(in Km) based on the GoogleMap stays as a EdgeCost. For example,I want to set these two cities as two vertexes of the my edge in the graph "Uppsala" -> "Marsta"(which is already). But as you can see the edge between two cities is just an arrow connecting two geographical locations of cities.I wanted them to use GoogleMap(or other GPS data) and set my edge on the map based on the shortest suggested route of GoogleMap.And set the calculated distance as EdgeCost value of created edge.Is it possible?

Answer 1

Here's a piece of the puzzle:

c1 = CityData["Boston", "Coordinates"];
c2 = CityData["New York", "Coordinates"];
address = "http://maps.googleapis.com/maps/api/distancematrix/json?origins=" <>
    ToString[c1[[1]]] <> "," <> ToString[c1[[2]]] <> "&destinations=" <>
    ToString[c2[[1]]] <> "," <> ToString[c2[[2]]] <> "&sensor=false"

which I modified from the google directions API. Now you can get the data from google:

distData = Import[address]

Per rm-rf's suggestion, you can get cleaner (easier to parse input) using

distData = Import[address, "JSON"]

which gives

{"destination_addresses" -> {"801 Montgomery Street, Brooklyn, NY 11213, USA"}, 
 "origin_addresses" -> {"Head Island Causeway, Boston, MA 02127, USA"}, 
 "rows" ->  {{"elements" -> {{"distance" -> {"text" -> "349 km", "value" -> 349019}, 
              "duration" -> {"text" -> "3 hours 45 mins", "value" -> 13477}, 
              "status" -> "OK"}}}}, 
 "status" -> "OK"}

Indexing into this

First[First[distData[[3, 2]]]][[2, 1, 1, 2, 1]]

gives

"text" -> "349 km"

Answer 2

This is only an attempt to answer the question, if I understood it correctly. You want to "cover the actual road connection between cities (...) based on the GoogleMap".

First step: find the coordinates of the two cities you want to use as edges in your graphic:

c1 = CityData["Sao Paulo", "Coordinates"];
c2 = CityData["Rio de Janeiro", "Coordinates"];

Second step: define the center of the map:

center = (c1 + c2)/2;

Third step: Import[] the actual Google Maps image based on the center you've specified

Import["http://maps.google.com/maps/api/staticmap?center=" <>ToString[center[[1]]] <> "," <> ToString[center[[2]]] <> "&zoom=6&size=400x400&sensor=false&maptype=roadmap&markers=color:blue%7Clabel:O%7C" <> ToString[c1[[1]]] <> "," <> ToString[c1[[2]]] <>"&markers=color:red%7Clabel:D%7C" <> ToString[c2[[1]]] <> "," <> ToString[c2[[2]]]]

EDITED

After some research, I think it can also be done:

Define the cities:

from = ToString[c1[[1]]] <> "," <> ToString[c1[[2]]];
to = ToString[c2[[1]]] <> "," <> ToString[c2[[2]]];

Now use Mathematica to import data from Google with distance and time:

distdata = Import["http://maps.googleapis.com/maps/api/directions/json?origin=" <> from <> "&destination=" <> to <> "&region=es&sensor=false", {"HTML", "Source"}];

Now find distance by road:

roadDistance = StringSplit[StringSplit[distdata, ":"][[13]],","][[1]]

"429 km"

Now find travel time:

travelTime = StringSplit[StringSplit[distdata, ":"][[16]], ","][[1]]

"4 hours 44 mins"