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pythongoogle-colaboratorygisgeospatialshapefile
Viraj
Viraj

Reputation: 1

How do I download a GeoDataFrame to my local drive from Google Colab?

I am fairly new to SHAPEFiles and GeoDataFrames so apologies if this is a very basic question.

I am using Google Colab in Google Chrome on a Mac. Python version 3.xx

I have an existing Esri SHAPEFile that has CRS points (latitiude-longitude) of Polygons and MultiPolygons.

My objective was to find the centroid of these Polygons and MultiPolygons and add the centroids as a new column in the existing SHAPEfile and then save the file locally.

How do I save the file locally? What format do I use? Thanks.

Upvotes: 0

Views: 1025

Answers (1)

Thomas
Thomas

Reputation: 10065

import geopandas as gpd

df = gpd.read_file("polygons.shp")

df["geometry"] = df["geometry"].centroid  # assuming a projection CRS is used

df.to_file("centroids.shp", driver="Shapefile")

You'll need to refresh your working directory in Google Colabs to see the shapefile. Make sure you download all associated files as well.

Note: You cannot store more than one geometry in a shapefile.

The script creates a new shapefile using the centroids for the geometries but also keeping all other columns. That way you will be able to relate both datasets.

Here is a possible workflow:

  1. Create a new Jupyter notebook or open an existing one
  2. Create a zip file containing your shape file including all associated files
  3. Upload it to your Colabs working directory
    • I call the file polygons.zip in my example
  4. Run following code in a cell:
!pip install geopandas

import os
import tempfile
import zipfile
import glob

import geopandas as gpd

OUTPUT_SHAPE_FILE = "centroids.shp"
SHAPE_FILE_ZIP = "polygons.zip"

with tempfile.TemporaryDirectory() as wd:

    with zipfile.ZipFile(SHAPE_FILE_ZIP, "r") as shape_file_zip:
        shape_file_zip.extractall(wd)

    shape_file = os.path.join(wd, SHAPE_FILE_ZIP.replace(".zip", ".shp"))

    df = gpd.read_file(shape_file)

    df["geometry"] = df["geometry"].centroid  # assuming a projection CRS is used

    df.to_file(os.path.join(wd, OUTPUT_SHAPE_FILE), driver="Shapefile")

    shape_file_name = OUTPUT_SHAPE_FILE.replace(".shp", "")

    with zipfile.ZipFile(f"{shape_file_name}.zip", "w") as output_file:

        for file in glob.iglob(f"{os.path.join(wd, shape_file_name)}.*"):
            output_file.write(file, os.path.basename(file))
  1. Refresh your working directory on Google Colabs, you'll see centroids.zip
  2. Download the file (click on the three dots when hovering over the file)

PS. I would recommend to use a local Jupyter notebook and Python environment for such situations.

Upvotes: 1

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