Is it possible to fit a coordinate to a street in OSMnx?

user_4737417 0
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OSMnx provides solution to calculate the shortest path between two nodes, but I would like to the same with points on streets (I have GPS coordinates recorded from vehicles). I know there is also a method to get the closest node, but I have two question for this problem of mine.

i) When closest node computed is the street where the point is also taken into consideration? (I assume not) ii) If I wanted to implement something like this, I like to know how a street (edge) is represented as a curve (Bézier curve maybe?). Is it possible to get the curve (or the equation of the curve) of an edge?

I asked this question here, because the guidelines for contributing of OSMnx asked it.

networkx openstreetmap python
2 Answers

OSMnx was recently updated since there have been a couple of requests in this direction (see https://github.com/gboeing/osmnx/pull/234 and references therein). So in the last update, you'll find a function like this:

ox.get_nearest_edge(G, (lat, lon))

It will give you the ID of the nearest edge, which is much better than nearest nodes. However, I think it is more useful to also get the actual distance of the nearest edge in order to check whether or not your data point is on the road or a few thousand meters apart...

To do this, I followed the implementation from https://github.com/gboeing/osmnx/pull/231/files

# Convert Graph to graph data frame
gdf = ox.graph_to_gdfs(G, nodes=False, fill_edge_geometry=True)
# extract roads and some properties
roads = gdf[["geometry", "u", "v","ref","name","highway","lanes"]].values.tolist()
# calculate and attach distance
roads_with_distances = [(road, ox.Point(tuple(reversed((lat,lon)))).distance(road[0])) for road in roads]

# sort by distance
roads_with_distances = sorted(roads_with_distances, key=lambda x: x[1])
# Select closest road
closest_road = roads_with_distances[0]
# Check whether you are actually "on" the road
if closest_road[1] < 0.0001: print('Hit the road, Jack!')

I have the impression that a distance on the order of $10^{-5}$ means that the coordinate is actually "on" the road.

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