GeoPandas Shapefile – Reading N Number of Rows from Shapefile Using GeoPandas

data-framegeopandasshapefile

Pandas has a parameter nrows for selecting how many rows will be read into the DataFrame.

Does GeoPandas have a similar parameter? Couldn't find in the documentation.

Best Answer

See Only read specific rows of a shapefile with GeoPandas / Fiona:

import geopandas as gpd
import fiona

c = fiona.open(r'C:\someshapefile.shp')
df = gpd.GeoDataFrame.from_features(c[0:5])

Related Solutions

GeoPandas Shapefile Attributes – Read Specific Attribute Columns of a Shapefile with GeoPandas/Fiona

Building on gene's answer, you can use GeoDataFrame.from_features

The following should do the trick:

import fiona

def records(filename, usecols, **kwargs):
    with fiona.open(filename, **kwargs) as source:
        for feature in source:
            f = {k: feature[k] for k in ['id', 'geometry']}
            f['properties'] = {k: feature['properties'][k] for k in usecols}
            yield f

And then

gpd.GeoDataFrame.from_features(records(filename), ['prop1', 'prop2'])

I'd be curious to know if this speeds up your code, or if the properties need to be ignored in Fiona rather than the GeoDataFrame construction.

Python GeoPandas – How to Convert Shapefile from Pandas Back to GeoPandas

When joining 2 GeoDataFrames by an attribute (so a merge with pandas and not a spatial join, which can certainly be sensible for a given application), the result will be a pandas DataFrame and not a GeoDataFrame.
It will also have two columns with geometry data (one of each original GeoDataFrame), and you will need to decide which of those columns you want to have as the 'active' geometry column (i.e. the column that is used for the spatial methods called on that GeoDataFrame).

Therefore, you need to explicitly convert it back to a GeoDataFrame specifying which geometry column should be used:

GeoDataFrame(final, geometry='name_of_geometry_name')

Best Answer

Related Solutions

GeoPandas Shapefile Attributes – Read Specific Attribute Columns of a Shapefile with GeoPandas/Fiona

Python GeoPandas – How to Convert Shapefile from Pandas Back to GeoPandas

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