Leaflet-Solr-Heatmap

A Leaflet plugin that supports spatial exploration and visualizes heatmap facets from Solr 5.x

Demo

This code is running under GitHub Pages. Two demos are available. The first provides a big map of JSTOR data and shows how to integrate the library. The second allows you to run the code against your Solr instance. The UI includes a form so you can provide the URL of your Solr instance and a few details about your schema. The repository's GitHub wiki provides more information.

Using with Leaflet

// Create a SolrHeatmap layer and add it to the map
var solr = L.solrHeatmap('http://127.0.0.1:8983/solr/gettingstarted', {
  // Solr field with geospatial data (should be type Spatial Recursive Prefix Tree)
  field: 'loc_srpt',

  // Set type of visualization. Allowed types: 'geojsonGrid', 'clusters', 'heatmap'
  // Note: 'clusters' requires LeafletMarkerClusterer
  type: 'geojsonGrid'
}).addTo(map);

Option	Type	Default	Description
field	String	null	Required. Solr field with geospatial data (should be type Spatial Recursive Prefix Tree)
type	String	'geojsonGrid'	Type of visualization. Accepts geojsonGrid, clusters and heatmap
solrRequestHandler	String	'select'	Request handler for Solr
colors	Array	['#f1eef6', '#d7b5d8', '#df65b0', '#dd1c77', '#980043']	Colors for heatmap. Array can be of any length.
maxSampleSize	Number	Number.MAX_SAFE_INTEGER	For improved performance, run Jenks classification on only a sample of Solr counts. Default value turns off sampling. Typical value is 400.
popupDisplay	various	false	on mouse click optionaly display nearby documents in popup, defaults to ignoring clicks
nearbyField	String	null	computing documents near a mouse click, BBox required for non-point data
nearbyFieldType	String	'BBox'	either BBox or RPT
sortField	String	null	when present, used to sort results for pop-up in desc order
popupHighlight	Boolean	false	on mouseover in popup list of nearby items, items and their boudning boxes can be highlighted
solrSuccessHandler	function	null	user function to call during processing of Solr heatmap results, args: data, textStatus, jqXHR
solrErrorHandler	function	null	user function to call when Solr heatmap response was an error, args: jqXHR, textStatus, errorThrown
solrNearbySuccessHandler	function	null	user function to call during processing of Solr "nearby" results, args: data, textStatus, jqXHR
solrNearbyErrorHandler	function	null	user function to call when Solr "nearby" response was an error, args: jqXHR, textStatus, errorThrown
renderCompleteHandler	function	null	user function to call after rendering of Solr heatmap response is complete
showGlobalResults	boolean	false	should we display a popup in the corner of the map listing results from the entire map
fixedOpacity	number or false	false	the single opacity value to use for all heatmap colors
filterQuery	string or false	false	the initial filter query to apply

Popup Display

When the user clicks on the map, the heatmap layer can popup a window with information on nearby Solr documents. Nearby is defined as Solr documents within the size of a heatmap bubble cell. On map clicks, use Solr intersection if nearby field type is BBox. If nearby field type is RPT, assume it only holds point data and use geofilt/geodist. Note that your Solr instance may crash if your RPT field contains non-point data (e.g., envelopes or polygons) and you run a geofilt/geodist query against it.

To display popups, set popupDisplay to the name of the Solr field you would like displayed. If you need more than one field displayed, set popupDisplay to a comma seperated list of Solr field names. If you want to change the formatting of a single field, rather than providing the field name provide an array whose first element is the field name and second element a function that takes a Solr document. This function should return the html description of the field. You can also override the popup completely. Simply set popupDisplay to a function that accepts three arguments, the entire Solr response, the location of the click and the solr heatmap layer object. This function can use a popup, display the results in some other div on the page, etc.

If the sort field is provided, the results in the popup are sorted from largest to smallest

// how to specify popup
var solr = L.solrHeatmap("http://localhost:8983/solr/coreName", 
{
  field: 'bounds_rpt',
  type: 'heatmap',
  bboxField: 'bounds_bbox',
  popupDisplay: ['title',['doi', function(doc) {return formatDoi(doc);}],'count']
}.addTo(map);

// where title, doi and count are Solr field names 
// and formatDoi is a local Javascript function that returns the html
// representation of the doi field

Including Keyword Searches

The library makes requests directly to Solr. In your application you may want to augment this request with addtional filter queries to support keyword searching or otherwise limiting results. To support this, the library provides the function "addFilterQuery". The string should be in Solr's filter query syntax (e.g., title:Water). The exact details (such as whether or not to include * symbols) depend on the type of field you are searching. You should not include "fq=" in the parameter, it will be prepended. To set multiple filters, call addFilterQuery multiple times. To delete all filter queries, call clearFilterQueries.

Setting a filter query does not automatically update the heatmap. After changing the filter queries, call the refresh method to generate a new heatmap. Note that refresh does not revisit any of the configuration parameters passed to the constructor. You can not, for example, try to change the URL to the Solr instance or fields in the popup and then call refresh. If you are changing configuration parameters, you should call the constructor and make a new object.

Running locally

Download required libraries for example (Leaflet, Leaflet MarkerClusterer, jQuery)

bower install

(Optional) Install packages for running local server

npm install

Start local server

grunt

View the example at http://127.0.0.1:8000/example/