Geopandas warning on read_file()

Question

I'm getting the following warning reading a geojson with geopanda's read_file():

...geodataframe.py:422: RuntimeWarning: Sequential read of iterator was interrupted. Resetting iterator. This can negatively impact the performance.
  for feature in features_lst:

Here's the code sample I used:

crime_gdf = gpd.read_file('datasets/crimes.geojson', bbox=bbox)

crimes.geojson is a file containing a large number of points, each with a 'Crime type'

bbox defines the boundaries

The code runs as expected, but I don't understand that warning.

EDIT

I converted the geojson to feather, and I get the same warning.

Answer 1

While it could cause problems ignoring warnings in some contexts, I am finding this one particularly annoying repeated in my code output.

I found the warning can be ignored using

import warnings
# filter out RuntimeWarnings, due to geopandas/fiona read file spam
# https://stackoverflow.com/questions/64995369/geopandas-warning-on-read-file
warnings.filterwarnings("ignore",category=RuntimeWarning)

I added in the comments referencing this post to explain why I am filtering out these warnings. When this warning is suppressed in a future geopandas / fiona release then this code snippet should probably be removed, as it may also suppress meaningful warnings and could be problematic in some contexts.

Answer 2

See my comment in Fiona's issue tracker: https://github.com/Toblerity/Fiona/issues/986

GDAL (the library Fiona uses to access the geodata) maintains an iterator over the features that are currently read. There a some operations that, for some drivers, can influence this iterator. Thus, after such operations we have to ensure that the iterator is set to the correct position that a continuous read of the data is ensured. Such operations include counting all features in a dataset, respectively calculating its extent.

There are different types of drivers in GDAL. Some drivers support random access, while some do not. For the drivers that do not support random access, the resetting of the iterator involves reading all features again up to the iterator position. As this is a possible costly operation, this RuntimeWarning is emitted, so that users are aware of this behavior.