Geo Shapes in Elasticsearch
Introduction
Geo shapes in Elasticsearch enable you to index and query complex geometric shapes such as polygons, multipolygons, lines, and circles. This is particularly useful for geospatial data analysis and location-based queries.
Setting Up Elasticsearch
To work with geo shapes, you need to have Elasticsearch installed and running. You can use Docker to quickly set up Elasticsearch:
docker run -d -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" elasticsearch:7.10.1
Mapping Geo Shapes
To store geo shapes, you need to define a mapping for your index. The geo_shape field type is used to index shapes.
PUT /geo_shapes_example
{
"mappings": {
"properties": {
"location": {
"type": "geo_shape"
}
}
}
}
Indexing Geo Shapes
You can index various types of geo shapes such as points, lines, and polygons. Here are some examples:
Indexing a Point
POST /geo_shapes_example/_doc/1
{
"location": {
"type": "point",
"coordinates": [13.400544, 52.530286]
}
}
Indexing a Line
POST /geo_shapes_example/_doc/2
{
"location": {
"type": "linestring",
"coordinates": [
[13.400544, 52.530286],
[13.402, 52.532]
]
}
}
Indexing a Polygon
POST /geo_shapes_example/_doc/3
{
"location": {
"type": "polygon",
"coordinates": [
[
[13.400544, 52.530286],
[13.402, 52.532],
[13.405, 52.533],
[13.400544, 52.530286]
]
]
}
}
Querying Geo Shapes
Elasticsearch provides various ways to query geo shapes. You can use the geo_shape query to find documents that contain shapes that intersect with a specified shape.
Intersection Query
POST /geo_shapes_example/_search
{
"query": {
"geo_shape": {
"location": {
"shape": {
"type": "polygon",
"coordinates": [
[
[13.400544, 52.530286],
[13.402, 52.532],
[13.405, 52.533],
[13.400544, 52.530286]
]
]
},
"relation": "intersects"
}
}
}
}
Within Query
POST /geo_shapes_example/_search
{
"query": {
"geo_shape": {
"location": {
"shape": {
"type": "polygon",
"coordinates": [
[
[13.400544, 52.530286],
[13.402, 52.532],
[13.405, 52.533],
[13.400544, 52.530286]
]
]
},
"relation": "within"
}
}
}
}
Conclusion
In this tutorial, we have explored how to work with geo shapes in Elasticsearch. We have covered the basics of setting up Elasticsearch, defining mappings, indexing various types of geo shapes, and querying them. Geo shapes are powerful tools for geospatial data analysis and can be used in diverse applications such as mapping, location-based services, and more.