This extension contains view plugins to display geospatial files and services in CKAN. It contains an OpenLayers based viewer originally developed by Philippe Duchesne and other view plugins that used to be part of ckanext-spatial.
Note: This is a work in progress, if you can help with OpenLayers or Leaflet development, check the Issues section for what needs to be done or add a new issue.
This extensions supports CKAN 2.7 onwards, including Python 3 support on CKAN 2.9 or higher.
To install ckanext-geoview on a production site:
Activate your CKAN virtual environment, for example:
source /usr/lib/ckan/default/bin/activate
Install the ckanext-geoview Python package into your virtual environment:
pip install ckanext-geoview
Add the relevant plugins to the
ckan.pluginssetting in your CKAN config file (by default the config file is located at/etc/ckan/default/production.ini). Check Available plugins to see which ones are available and if they require further configuration.Add the
resource_proxyplugin to theckan.pluginssetting.Restart CKAN. For example if you've deployed CKAN with Apache on Ubuntu:
sudo service apache2 reload
To install ckanext-geoview for development:
Clone the source:
cd /usr/lib/ckan/default/src git clone https://github.com/ckan/ckanext-geoview.git
Activate your CKAN virtual environment, for example:
source /usr/lib/ckan/default/bin/activate
Install the ckanext-geoview Python package into your python virtual environment:
cd ckanext-geoview python setup.py develop
Continue with the main installation instructions above (step 3 onwards).
The OpenLayers viewer provides access to different geospatial formats and services:
To enable it, add geo_view to your ckan.plugins setting.:
ckan.plugins = ... resource_proxy geo_view
If you want the geospatial views to be created by default, add the plugin to the following setting:
ckan.views.default_views = ... geo_view
The formats and services supported are:
| Type | Resource format (*) |
|---|---|
| Web Map Service (WMS) | wms |
| Web Feature Service (WFS) | wfs |
| GeoJSON | geojson |
| GML | gml |
| KML | kml |
| ArcGIS REST API | arcgis_rest |
| Google Fusion Tables | gft |
(*) Resource formats are case insensitive
Support varies across formats, so you might want to deactivate the ones you are not interested in. To choose which formats to display, set the following configuration option:
ckanext.geoview.ol_viewer.formats = wms kml
To render Google Fusion Tables resources, a Google API Key must be provided in the ini file:
ckanext.geoview.gapi_key = <API Key here>
This key must be granted Fusion Tables permissions. More information on obtaining such a key can be found at https://developers.google.com/fusiontables/docs/v1/using#APIKey.
All configuration options relating to the OpenLayers viewer (ie those prefixed with ckanext.geoview.ol_viewer.*) are passed to the JavaScript module, where they are accessible on the options.ol_config object:
this.ckan.module('olpreview', function (jQuery, _) {
// ...
_onReady: function () {
console.log(this.options.ol_config)
}
// ...
}
Other available configuration options are:
- ckanext.geoview.ol_viewer.hide_overlays: if set to True, overlays won't be visible by default (only the base layer)
- ckanext.geoview.ol_viewer.default_feature_hoveron: if set to True, feature data popup will be displayed when hovering on
- ckanext.geoview.ol_viewer.forward_ogc_request_params: if set to True, OGC request parameters that may be present in resource URLs will be kept as part of proxied service requests. If False (default), such parameters will be removed from URL when proxying requests.
- Each instance of a view has the following configuration options that can override the global configuration :
- feature_hoveron: if set to True, feature data popup will be displayed when hovering on
- feature_style: JSON representation of an OpenLayers style, as accepted by the StyleMap constructor
Specific basemap support In addition to the basemap types described in Common base layers for Map Widgets, the OpenLayers viewer supports several other basemap types, namely TMS, WMTS, WMS
TMS example (here in Mercator projection)
ckanext.spatial.common_map.tms.url = <tms URL> ckanext.spatial.common_map.tms.srs = EPSG:900913 ckanext.spatial.common_map.tms.layername = <TMS layer name> ckanext.spatial.common_map.tms.resolutions = [156543.03390625,78271.516953125,39135.7584765625,19567.87923828125,9783.939619140625,4891.9698095703125,2445.9849047851562,1222.9924523925781,611.4962261962891,305.74811309814453,152.87405654907226,76.43702827453613,38.218514137268066,19.109257068634033,9.554628534317017,4.777314267158508,2.388657133579254,1.194328566789627,0.5971642833948135,0.29858214169740677,0.14929107084870338,0.07464553542435169,0.037322767712175846,0.018661383856087923,0.009330691928043961,0.004665345964021981,0.0023326729820109904,0.0011663364910054952,5.831682455027476E-4,2.915841227513738E-4,1.457920613756869E-4] ckanext.spatial.common_map.tms.extent = [-20037508.34, -20037508.34,20037508.34, 20037508.34]
WMTS (in this case parameters will be fetched from online capabilities)
ckanext.spatial.common_map.type = wmts ckanext.spatial.common_map.wmts.url = <wmts URL> ckanext.spatial.common_map.wmts.layer = <WMTS layer name> ckanext.spatial.common_map.wmts.srs = EPSG:4326
WMS
ckanext.spatial.common_map.wms.url = <wms URL> ckanext.spatial.common_map.wms.layer = <layer name> ckanext.spatial.common_map.wms.srs = EPSG:31370 ckanext.spatial.common_map.wms.extent = [141192.712000, 161464.403000, 158005.472000, 178169.335000]
Multi basemaps
Multiple basemaps can be defined in a separate file, and will result in a dropdown in the interface allowing to switch between basemaps. Basemap definition file is defined as follows
#ckanext.geoview.basemaps=%(here)s/basemaps.json
(here pointing to a file next to the ini file). This file is a JSON encoded array of basemap definitions reproducing the structure and syntax described above:
[
{
"title": "OSM",
"type" : "custom",
"url" : "http://tile.openstreetmap.org/{z}/{x}/{y}.png",
"attribution" : " Map tiles & Data by OpenStreetMap, under CC BY SA."
},
{
"title": "Blue Marble Mercator",
"type" : "tms",
"url" : "http://demo.opengeo.org/geoserver/gwc/service/tms/",
"srs" : "EPSG:900913",
"layername" : "nasa%3Abluemarble@EPSG%3A900913@png",
"resolutions" : [156543.03390625,78271.516953125,39135.7584765625,19567.87923828125,9783.939619140625,4891.9698095703125,2445.9849047851562,1222.9924523925781,611.4962261962891,305.74811309814453,152.87405654907226,76.43702827453613,38.218514137268066,19.109257068634033,9.554628534317017,4.777314267158508,2.388657133579254,1.194328566789627,0.5971642833948135,0.29858214169740677,0.14929107084870338,0.07464553542435169,0.037322767712175846,0.018661383856087923,0.009330691928043961,0.004665345964021981,0.0023326729820109904,0.0011663364910054952,5.831682455027476E-4,2.915841227513738E-4,1.457920613756869E-4],
"extent" : [-20037508.34, -20037508.34,20037508.34, 20037508.34]
},
{
"title": "Blue Marble 4326",
"type" : "tms",
"url" : "http://demo.opengeo.org/geoserver/gwc/service/tms/",
"srs" : "EPSG:4326",
"layername" : "nasa%3Abluemarble@EPSG%3A4326@png",
"resolutions" : [0.703125,0.3515625,0.17578125,0.087890625,0.0439453125,0.02197265625,0.010986328125,0.0054931640625,0.00274658203125,0.001373291015625,6.866455078125E-4,3.4332275390625E-4,1.71661376953125E-4,8.58306884765625E-5,4.291534423828125E-5,2.1457672119140625E-5,1.0728836059570312E-5,5.364418029785156E-6,2.682209014892578E-6,1.341104507446289E-6,6.705522537231445E-7,3.3527612686157227E-7],
"extent" : [-180,-90,180,90]
},
{
"title": "Opengeo WMS demo",
"type" : "wms",
"url" : "http://demo.opengeo.org/geoserver/ows",
"layer" : "ne:NE1_HR_LC_SR_W_DR",
"srs" : "EPSG:4326",
"extent" : [-180,-90,180,90]
}
]
When declared, this basemap list will override the ckanext.spatial.common_map properties.
URL specification
For WMS and WFS views, the URL must be specified carefully to get the desired result. In general, to browse the offered layers or features of a WMS or WFS endpoint, just specify the endpoint in the URL field of the resource, e.g.:
https://neo.sci.gsfc.nasa.gov/wms/wms
or
http://giswebservices.massgis.state.ma.us/geoserver/wfs
You can request individual layers/features using the "#" sign, e.g.:
https://neo.sci.gsfc.nasa.gov/wms/wms#MOD14A1_M_FIRE
or
http://giswebservices.massgis.state.ma.us/geoserver/wfs#GISDATA.MINLL1_ARC
N.B. For WFS this is the feature name without the qualifier, e.g. GISDATA.MINLL1_ARC and not massgis:GISDATA.MINLL1_ARC in the example above.
Note: This plugin used to be part of ckanext-spatial.
The Leaflet GeoJSON viewer will render GeoJSON files on a map and add a popup showing the features properties, for those resources that have a geojson format.
To enable it, add geojson_view to your ckan.plugins setting.:
ckan.plugins = ... resource_proxy geojson_view
If you want the views to be created by default on all GeoJSON files, add the plugin to the following setting:
ckan.views.default_views = ... geojson_view
You can use the ckanext.geoview.geojson.max_file_size configuration option to define the maximum file size (in bytes) that will be rendered in the map widget. Default is 25 Mb.
Note that this relies on the resource size field being set (ie it will only work with uploaded files, not linked externally).
The Leaflet WMTS viewer will render WMTS (Web Map Tile Service) layers on a map for those resources that have a wmts format.
To enable it, add wmts_view to your ckan.plugins setting.:
ckan.plugins = ... resource_proxy wmts_view
If you want the views to be created by default on all WMTS resources, add the plugin to the following setting:
ckan.views.default_views = ... wmts_view
The Leaflet Shapefile viewer will render ESRI Shapfiles (A ZIP archive contains the .shp, .shx, .dbf, and .prj files) on a map and add a popup showing the features properties, for those resources that have a shp format.
To enable it, add shp_view to your ckan.plugins setting.:
ckan.plugins = ... resource_proxy shp_view
If you want the views to be created by default on all Shapefiles, add the plugin to the following setting:
ckan.views.default_views = ... shp_view
The projection information (EPSG code, e.g., 4326 and 3857) will be loaded if there is a .prj file provided. You can also add a new field named 'resource_crs' in your custom resource fields or the following configuration option (The loading order is: .prj file, 'resource_crs' field, option and EPSG:4326/WGS84):
ckanext.geoview.shp_viewer.srid = 4326
The encoding of the shapefile can be defined by a custom resource field named 'encoding' in the metadata of the dataset or the following configuration option (The loading order is: 'encoding' field, option and UTF-8):
ckanext.geoview.shp_viewer.encoding = UTF-8
The geospatial view plugins support the same base map configurations than the ckanext-spatial widgets.
Check the following page to learn how to choose a different base map layer (Stamen, MapBox or custom):
http://docs.ckan.org/projects/ckanext-spatial/en/latest/map-widgets.html
ckanext-geoview should be availabe on PyPI as https://pypi.python.org/pypi/ckanext-geoview. If that link doesn't work, then you can register the project on PyPI for the first time by following these steps:
Create a source distribution of the project:
python setup.py sdist
Register the project:
python setup.py register
Upload the source distribution to PyPI:
python setup.py sdist upload
Tag the first release of the project on GitHub with the version number from the
setup.pyfile. For example if the version number insetup.pyis 0.0.1 then do:git tag 0.0.1 git push --tags
ckanext-geoview is availabe on PyPI as https://pypi.python.org/pypi/ckanext-geoview. To publish a new version to PyPI follow these steps:
Update the version number in the
setup.pyfile. See PEP 440 for how to choose version numbers.Create a source distribution of the new version:
python setup.py sdist
Upload the source distribution to PyPI:
python setup.py sdist upload
Tag the new release of the project on GitHub with the version number from the
setup.pyfile. For example if the version number insetup.pyis 0.0.2 then do:git tag 0.0.2 git push --tags