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A mappyfile plugin to convert GeoJSON to inline features

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mappyfile-geojson

A mappyfile plugin to convert GeoJSON to inline Mapfile features. Useful for adding dynamically created features (from web services, user created features, and other external data sources) to a map, or to quickly visualise a geometry.

Note - to display entire GeoJSON files MapServer can be configured to read GeoJSON as an input OGR source using the GeoJSON driver.

import geojson
import mappyfile
# import directly
import mappyfile_geojson
# can also be imported as plugin using
from mappyfile.plugins import mappyfile_geojson

gj = geojson.load(fn)
l = mappyfile_geojson.convert(gj)
print(mappyfile.dumps(l))

Converts the following JSON:

{
  "type": "Feature",
  "geometry": {
    "type": "LineString",
    "coordinates": [
      [ 102.0, 0.0 ],
      [ 103.0, 1.0 ],
      [ 104.0, 0.0 ],
      [ 105.0, 1.0 ]
    ]
  },
  "properties": {
    "prop0": "value0",
    "prop1": 0.0
  }
}

to the following Mapfile LAYER:

LAYER
    EXTENT 102 0 105 1
    STATUS ON
    TYPE LINE
    PROCESSING "ITEMS=prop0,prop1"
    FEATURE
        ITEMS "value0;0.0"
        POINTS
            102.0 0.0
            103.0 1.0
            104.0 0.0
            105.0 1.0
        END
    END
END

Demo

An example of using the plugin with mappyfile can be found in example.py along with an example.map.

https://raw.githubusercontent.com/geographika/mappyfile-geojson/master/polygon.png

A further example, creating images for each of the test cases using mapscript is available at create_images.py.

The sample output images are in the images folder.

Requirements

  • Python 3.8+
  • mappyfile (the plugin can be used on its own but will create a dictionary object structured to use within mappyfile). Installing mappyfile should be done separately.

Installation

Note installing the mappyfile-geojson plugin will automatically install the required dependency geojson.

pip install mappyfile
pip install mappyfile-geojson

Notes

  • Can calculate extent of input features, with an optional buffer (by passing an extent_buffer to the convert function)

  • Multipart features are supported

  • Coordinate sequences with Z values are supported, but Z values are ignored as they are not supported in Mapserver inline features.

  • As a MapServer LAYER only supports a single geometry type, all features in the GeoJSON file should also be of the same type (however a mix of multipart and non-multipart features is supported e.g. LineString and MultiLineString)

  • Nested JSON properties are not supported:

    "properties": {
        "prop0": "value0",
        "prop1": { "this": "that" }
    }

    Will become:

    ITEMS "value0;{u'this': u'that'}"

Releases

1.0 (02/10/2023)

  • Drop support for Python 2.7
  • Update of GeoJSON and mappyfile dependencies
  • Code reformatted using black

0.4 (09/02/2020)

  • Automated Windows testing
  • Automated release process
  • Set geojson dependency version
  • Fix failing tests due to precision issue differences between py2 and py3
  • Use integers for layer EXTENT where possible e.g. 5 instead of 5.0

0.3 (29/08/2018)

  • Add support for MultiPoint, MultiLineString, and MultiPolygon
  • Allow coordinates with Z values (previously these would crash the script)
  • Updated README

0.2 (15/02/2018)

  • Unicode support

0.1 (06/02/2018)

  • Initial release

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A mappyfile plugin to convert GeoJSON to inline features

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