Node-RED block in Snap4City Microservice library node-red-contrib-snap4city-user is "event-search-within-circle">
    <p>It allows to retrieve the geolocated entities (not only services) that match with a list of keywords. The results can
        be possibly filtered to be within a specified distance from a GPS position./p>

        <h3>Inputs</h3>
        A JSON with these parameters:

        <dl class="message-properties">
            <dt>latitude
                <span class="property-type">number</span>
            </dt>
            <dd> latitude of a GPS position</dd>
            <dt>longitude
                <span class="property-type">number</span>
            </dt>
            <dd> longitude of a GPS position</dd>
            <dt>range
                <span class="property-type">string</span>
            </dt>
            <dd> time range for the events to be retrieved, it can be ‘day’ for the events of the day of the request, ‘week’ for
                the events in the next 7 days or ‘month’ for the events in the next 30 days (if omitted ‘day’ is assumed).
                <dt>maxdistance
                    <span class="property-type">number</span>
                </dt>
                <dd> maximum distance from the GPS position of the services to be retrieved, expressed in Km (0.1 is used if parameter
                    is missing) if it is equal to “inside” it searches for services with a WKT geometry that contains the
                    specified GPS position (e.g a park)</dd>
                <dt>maxresults
                    <span class="property-type">number</span>
                </dt>
                <dd> maximum number of results to be returned (if parameter is missing 100 is assumed), if it is 0 all results
                    are returned</dd>
        </dl>

        <h3>Outputs</h3>
        <ol class="node-ports">
            <li>ServiceUri Array
                <dl class="message-properties">
                    <dd> Returns an array containing the servicesUri of each service found</dd>
                </dl>
            </li>
            <li>GeoJSON Results
                <dl class="message-properties">
                    <dd> the results format is a GeoJSON “FeatureCollection” with the matching events. For each “Feature” a set
                        of properties is provided.d</dd>
                </dl>
            </li>
        </ol>

        <h3>Details</h3>
        <p>The node can receive a JSON with the parameters described in the Inputs section and with them generate the output
            JSON. If the values are not present in the input JSON, these are read by those in the configuration. If they
            are not present in either part, an error is generated for the necessary parameters.</p>