PyGeoj
PyGeoj is a simple Python GeoJSON file reader and writer intended for end-users. It exposees dictionary structures as high level objects with convenience methods, so the user does not have to get caught up in the details of the format specification.
Platforms
Python 2 and 3.
Dependencies
Pure Python, no dependencies.
Installing it
PyGeoj is installed with pip from the commandline:
pip install pygeoj
It also works to just place the "pygeoj" package folder in an importable location like "PythonXX/Lib/site-packages".
Example Usage
Begin by importing the pygeoj module:
import pygeoj
Reading
Reading geojson formatted GIS files is a simple one-liner (requires the geojson file to be a "FeatureCollection"):
testfile = pygeoj.load(filepath="testfile.geojson") # or testfile = pygeoj.load(data=dict(...))
Basic information about the geojson file can then be extracted, such as:
len(testfile) # the number of features testfile.bbox # the bounding box region of the entire file testfile.crs # the coordinate reference system testfile.all_attributes # retrieves the combined set of all feature attributes testfile.common_attributes # retrieves only those field attributes that are common to all features
Individual features can be accessed by their index in the features list:
testfile[3] # or testfile.get_feature(3)
Or by iterating through all of them:
for feature in testfile:
# do something
A feature can be inspected in various ways:
feature.properties feature.geometry.type feature.geometry.coordinates feature.geometry.bbox
Editing
The standard Python list operations can be used to edit and swap around the features in a geojson instance, and then saving to a new geojson file:
testfile[3] = testfile[8]
# or testfile.replace_feature(3, testfile[8])
del testfile[8]
# or testfile.remove_feature(8)
testfile.save("test_edit.geojson")
An existing feature can also be tweaked by using simple attribute-setting:
# set your own properties
feature.properties = {"newfield1":"newvalue1", "newfield2":"newvalue2"}
# borrow the geometry of the 16th feature
feature.geometry = testfile[16].geometry
Note that when changing geometries or coordinates, you must remember to update its bbox to clear away any older stored bbox information.
feature.geometry.update_bbox()
Constructing
Creating a new geojson file from scratch is also easy:
newfile = pygeoj.new() # The data coordinate system defaults to long/lat WGS84 or can be manually defined: newfile.define_crs(type="link", link="http://spatialreference.org/ref/epsg/26912/esriwkt/", link_type="esriwkt")
The new file can then be populated with new features:
newfile.add_feature(properties={"country":"Norway"},
geometry={"type":"Polygon", "coordinates":[[(21,3),(33,11),(44,22)]]} )
newfile.add_feature(properties={"country":"USA"},
geometry={"type":"Polygon", "coordinates":[[(11,23),(14,5),(66,31)]]} )
Finally, some useful additional information can be added to top off the geojson file before saving it to file:
newfile.add_all_bboxes()
newfile.update_bbox()
newfile.add_unique_id()
newfile.save("test_construct.geojson")
More Information:
License:
This code is free to share, use, reuse, and modify according to the MIT license, see license.txt
Credits:
- Karim Bahgat
- Mec-iS
Changes
1.0.0 (2018-09-14)
- Bump to stable version
- Officially support Python 3
0.2.5 (2017-02-19)
- Fixed more robust validation to avoid unexpected errors
- Added skiperror option
- Fixed feat type missing when add_feature()
- Fixed crs not saving
- Added fixerror option when loading and validating
- Fix bug to allow null geometries and empty properties, and correctly represent them in json as null
0.2.4 (2015-07-11)
- Fixed bug with add_all_bboxes() not updating existing bboxes
- Fixed bug with GeojsonFile bbox sometimes being calculated wrong.
- Added update_bbox() on individual Geometry objects.
