geographika/mappyfile-geojson

A mappyfile plugin to convert GeoJSON to inline features

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.

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

Author

• Seth Girvin @geographika