Real-time view on what entities are nearby with respect to geofence radius
Overview
Often when performing real-time geospatial analytics the objective is to gain a view of what entities are nearby such as friends, businesses, local interests, cell towers etc,. This processor provides the ability to perform such a function using a configurable search area and entities that may be of concern.
A geo search is performed against a spatial index using the passed event attributes which will return 0 or more nearby entities.
Example & DSL attributes
geo search:
name: nearbyCellTowers
search area: 8
spatial index:
top left coordinates: [ 0,0 ]
width: 512
area: 262144
max levels: 6
preferred max elements: 601
spatial entities:
parser: com.fractalworks.streams.processors.geospatial.domain.telco.CellTowerArrowParser
source: data/mini_cells.csv
Custom field name to place result of search lookup
String
Default: geoSearchResult
latitude field
Custom field name to gain latitude dimension
String
Default: latitude
longitude field
Custom field name to gain longitude dimension
String
Default: longitude
convertWGS84ToTileCoords
Flag to convert WGS84 coordinates to tile coordinates
Boolean
Default: true
spatial index
An area is set out as a search tree. The default area is a flattened world divided out in to rectangles.
spatial entities
Spatial entities to return on a successful search
Spatial Entities
These are entities that have the required location attributes that enable the search algorithm to be executed against. Since entities are specific to the use case and business domain and/or industry the ability to leverage these assets within Joule a parser API is provided. The parser translates existing entity structures, via a file, in to a support Joule data structure.
Parser example
/*
* Copyright 2020-present FractalWorks Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
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* See the License for the specific language governing permissions and
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package com.fractalworks.streams.processors.geospatial.domain.telco;
import com.fractalworks.streams.core.exceptions.TranslationException;
import com.fractalworks.streams.sdk.referencedata.serialization.ReferenceDataArrowParser;
import org.apache.arrow.vector.FieldVector;
import org.apache.arrow.vector.VectorSchemaRoot;
/**
* CellTower Arrow row parser.
* <p>
* Format
* - radio,mcc,net,area,cell,unit,lon,lat,range,samples,changeable,created,updated,averageSignal
* <p>
* Created by Lyndon Adams
*/
public class CellTowerArrowParser implements ReferenceDataArrowParser<CellTower> {
/**
* Parse provided vectorSchemaRoot to CellTower.
*
* @param row
* @return CellTower
*/
@Override
public CellTower translate(VectorSchemaRoot row) throws TranslationException {
CellTower cellTower = new CellTower();
for(FieldVector v : row.getFieldVectors()){
var str = v.getObject(0);
switch (v.getName().toLowerCase() ){
case "radio" -> cellTower.setRadioType(RadioType.getEnum(str.toString().intern()));
case "mcc" -> cellTower.setMcc( ((Long)str).intValue());
case "net" -> cellTower.setNet(((Long)str).intValue());
case "area" -> cellTower.setArea(((Long)str).intValue());
case "cell" -> cellTower.setCell(((Long)str).intValue());
case "unit" -> cellTower.setUnit( (str!=null) ? ((Long)str).intValue() : -1);
case "lon" -> cellTower.setLon((Double)str);
case "lat" -> cellTower.setLat((Double)str);
case "range" -> cellTower.setRange(((Long)str).intValue());
case "samples" -> cellTower.setSamples(((Long)str).intValue());
case "changeable" -> cellTower.setChangeable(((Long)str).intValue());
case "created" -> cellTower.setCreated((Long) str);
case "updated" -> cellTower.setUpdated((Long) str);
case "averagesignal" -> cellTower.setAverageSignal( (str!=null) ?((Long)str).intValue() : -1);
default -> throw new TranslationException(String.format("Unknown field '%s'", v.getName()));
}
}
return cellTower;
}
}
