Type Error with truncate_graph_polygon function about osmnx HOT 3 CLOSED

truncate_graph_polygon is an under-the-hood function that I ended up exposing. It uses intersect_index_quadrats but doesn't expose some of its arguments. Thus, it works fine when you're using lat-long geometries, but chokes on projected geometries. The fix is to expose those arguments, which I just did in ba1d1b3. Thus your code should work in the latest GitHub version of OSMnx. Here's a small working example:

import osmnx as ox
ox.config(use_cache=True, log_console=True)
G = ox.graph_from_place('Piedmont, CA, USA', network_type='drive')
G = ox.project_graph(G)
gdf = ox.gdf_from_place('Piedmont, CA, USA')
poly = gdf['geometry'].iloc[0]
poly, crs = ox.project_geometry(poly)
poly = poly.buffer(-500)
G_truncated = ox.truncate_graph_polygon(G, poly, retain_all=False, truncate_by_edge=False, 
                                        quadrat_width=1000, buffer_amount=0.01)
fig, ax = ox.plot_graph(G_truncated)

The quadrat_width and buffer_amount arguments are in the polygon's units. So, here, we projected the polygon to UTM and thus the units are in meters.

In the meantime (pending these commits getting packaged and released), you can still make this work using OSMnx versions < 0.5. The trick is to work in all lat-long, and only project at the end:

import osmnx as ox
ox.config(use_cache=True, log_console=True)
G = ox.graph_from_place('Merced County, California, USA', network_type='drive_service')
place_names = ['Merced, California, USA', 
               'Atwater, California, USA',
               'Livingston, California, USA']
merced_cities = ox.gdf_from_places(place_names)
merced_polygon = merced_cities['geometry'].iloc[0]
g_sample = ox.truncate_graph_polygon(G, merced_polygon, retain_all=False, truncate_by_edge=False)
g_sample_projected = ox.project_graph(g_sample)
fig, ax = ox.plot_graph(g_sample_projected)

Note that as of OSMnx v0.15.0, the gdf_from_place and gdf_from_places functions have been deprecated and replaced by the geocode_to_gdf function. See the docs for details.

from osmnx.

Just wanted to chime in and ask a short follow up question/s.

So osmnx.project_gdf()'s functionality is to: "Project a GeoDataFrame to the UTM zone appropriate for its geometries' centroid."

Is the purpose of this step purely for rendering purposes? That is, is the intent to prepare the geometries to be rendered in a manner that is less distorted?

In @kelanstoy's example, there is no advantage necessarily in that process to re-projecting the data at that step, right? One could simply work in web mercator/latlng until one is ready to plot the results and then use the project_gdf function. Otherwise, one would be fine leaving it "as is" during their analysis.

from osmnx.

There are various reasons to project spatial data from an (approximately) spheroidal coordinate system like lat-long to a planar coordinate system like UTM. Like you mentioned, you might want to display it in two dimensions, such as on a sheet of paper or on a computer screen. Or you might want to have your geometries in units that are more meaningful than degrees -- typically meters.

from osmnx.