Vector tiles buffer is used to include data that is just outside of the tile. This data is used to prevent border effects when rendering the geometries. It is currently [hardcoded to 5 pixels](https://github.com/elastic/elasticsearch/blob/de2781f98696c1e6cfad2b5bf46fe752a5e3edbb/x-pack/plugin/vector-tile/src/main/java/org/elasticsearch/xpack/vectortile/feature/FeatureFactory.java#L63) but it should probably need to be user configurable by adding a new property on the vector tiles API which can change the value.




x-pack/plugin/vector-tile/src/main/java/org/elasticsearch/xpack/vectortile/rest/VectorTileRequest.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */
package org.elasticsearch.xpack.vectortile.rest;
import org.elasticsearch.common.Strings;
import org.elasticsearch.core.Booleans;
import org.elasticsearch.core.CheckedFunction;
import org.elasticsearch.geometry.Rectangle;
import org.elasticsearch.index.query.AbstractQueryBuilder;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.script.Script;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.PipelineAggregationBuilder;
import org.elasticsearch.search.aggregations.bucket.geogrid.GeoTileUtils;
import org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.MetricsAggregationBuilder;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.FieldAndFormat;
import org.elasticsearch.search.sort.ScriptSortBuilder;
import org.elasticsearch.search.sort.SortBuilder;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.xcontent.ObjectParser;
import org.elasticsearch.xcontent.ParseField;
import org.elasticsearch.xcontent.XContentParser;
import java.io.IOException;
import java.util.ArrayList;