Скачать или смотреть Resolving TypeError: unhashable type: 'LineString' When Using ox.simplify_graph() in Python

Encountering a `TypeError` when trying to simplify a graph using OSMnx? Discover the solution here to successfully simplify your geospatial data with `ox.simplify_graph()`.
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Understanding the Issue: TypeError in OSMnx Simplification

When working with geospatial data and network graphs in Python, you might encounter various challenges that can disrupt your workflow. One such common issue arises while using the ox.simplify_graph() function from the OSMnx library, leading to the error:

[[See Video to Reveal this Text or Code Snippet]]

This error typically occurs when trying to simplify a graph built from geospatial data, where the geometry attributes may not be in a compatible format. Let's break down the solution in a systematic way to help you navigate through this issue.

Root Cause of the Error

Your graph, which you may have constructed using a GeoDataFrame containing edges and nodes, might retain unhashable attributes—specifically LineString geometries. The simplify_graph function attempts to deduplicate and consolidate edge attributes, and when it encounters these geometries as attributes, it fails, leading to the TypeError.

Typical Graph Construction

A typical construction process might involve:

Building a graph from a dictionary of edges.

Utilizing GeoDataFrame structures to manage edge and node geometries.

Here’s a simplified look at how your GeoDataFrames might look:

Edge GeoDataFrame Example:

idrefnamespeedlimlengthgeometryuvkey11452ref1name15015LINESTRING (10.5 60.4, 10.5 60.4)119327160Node GeoDataFrame Example:

xyidgeometry10.560.411604POINT (10.5 60.4)Solution: Removing Unhashable Attributes

The remedy for this error involves removing the geometry attributes from your edges before calling the simplify_graph() function. Here’s how you can efficiently do that:

Step-by-Step Solution

Define the Attributes to Remove: Identify the attributes that are causing the issue, particularly the geometry attribute in this case.

Iterate Through Edges and Remove: Loop through each edge in the graph and remove the problematic attributes.

Here's the code snippet that reflects this solution:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following the steps outlined above, you should be able to successfully resolve the TypeError: unhashable type: 'LineString' and streamline your geospatial data manipulation with OSMnx. Remember, when encountering similar issues, checking for unhashable types in your graph attributes can often lead you to the solution.

Stay engaged with your Python projects, and happy coding!