I am struggling with DWithin queries in geomesa.
I have ingested many geo points from OSM and want to make DWithin queries.
I have the following code for query:
val query = new Query("t1", ECQL.toFilter("DWITHIN(geo_point, POINT (14.453943 60.499611), 5000, meters)"))
I expect geomesa to answer with the points not far then 5000 meters from POINT (14.453943 60.499611) (points 2,3,4 on the map).
But geomesa gives me more points than expected.
All the points in the map (1,2,3,4,5,6) are returned for this query.
It seems that geomesa can't properly filter out the points for DWithin query since it does not have support for geodesic distance checks.
So, is there any way to make DWITHIN query work correctly (in a geodesic manner) with geomesa?
Thanks!
GeoMesa uses the geotools dwithin filter function for such queries. Unfortunately, the function only supports native distances (i.e. degrees in WGS84).
Currently, your best bet is to use the geotools GeodeticCalculator class to create a polygon covering your query area and use that in an intersects filter. Alternatively, you could post-filter the results using the Geodetic Calculator.
Going forward, I've created a ticket to handle this use case better in GeoMesa: https://geomesa.atlassian.net/browse/GEOMESA-2263
Related
In point cloud filtering, there is radius filtering, that is, filtering inside the sphere. I want to change the range of filtering from sphere to ellipsoid. How to achieve this.I want to do it in c++ or python.I have tried to read the code of RadiusOutlierRemove in PCL, but it is still not clear how to construct an ellipsoid for filtering, and whether the search strategy still uses knn.
RediSearch looks promising after reading https://redislabs.com/blog/search-benchmarking-redisearch-vs-elasticsearch/.
We use elasticsearch currently. We rely heavily on its polygon query feature https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-geo-polygon-query.html.
I couldn't find polygon query in RediSearch. Is it there under different name? Is there anyone out using RediSearch for polygon query? How do you achieve that?
For now, only option I see is to use Geo filter to get points in different circles, and then find intersection of those with my polygon in application code.
I'm in the exact same boat, and it seems like as of v1.4.8 geo filters are limited to geo radius filters. However, it does look like an issue was created to add support for geo polygon filters:
https://github.com/RedisLabsModules/RediSearch/issues/680
I have a data set of about 20 million coordinates. I want to be able to pass in a latitude, longitude, and distance in miles and return all coordinates that are within the mile range of my given coordinates. I need the response time to ideally be sub 50ms.
I have tried loading all coordinates in memory in a golang service which, on every request, will loop through the data and using haversine filter all coordinates which are within the given miles distance of my given coordinate.
This method sees the results return in around 2 seconds. What approach would be good to increase the speed of the results? I am open to any suggestions.
I am toying around with the idea of grouping all coordinates by degree and only filtering by the nearest to the given coordinates. Haven't had any luck improving the response times yet though. My data set is only a test one too as the real data could potentially be in the hundreds of millions.
I think that this is more of a data structure problem. One good way to store large sets of geospatial coordinates is with an R-tree. It provides logn M search. I have limited knowledge of Go, but I have used an R-Tree to great effect for similarly sized datasets in a similar use case in a JS application. From a quick search it appears as though there are at least a couple Go R-Tree implementations out there.
Idea would be to have a "grid" that partitions coordinates, so that when you do need to do a lookup you can safely return all coordinates in particular cell, do not return any from the cells too far away from target, and only do per coordinate comparison for coordinates that are in the cells that contains some coordinates within distance and some outside the distance.
Simplified to 1D:
Coordinates are from 1 to 100
you partition into 5 blocks of 20
When somebody looks for all coordinates within distance 25 from 47
you return all coordinates in blocks [30,39], [40,49],[50,59],[60,69] and then after doing per coordinate analysis for blocks [20,29] and [70,79] you additionally return 22,23,24,25,26,27,28,29, 70,71,72.
Unfortunately I have no realistic way to estimate speedup of this approach so you would need to implement it and benchmark it by yourself.
MongoDB has various geographic searches $geoNear will allow you to search for points within a specific distance from a point or within a shape.
https://docs.mongodb.com/manual/reference/operator/aggregation/geoNear/
PostGIS for Postgres has something similar, but I am not too familiar with it.
How to search geo-point with polygon across dateline(International Date Line,or 180 and -180 longitude) use java api?
Hello everyone:
I use ElasticSearch 2.1 and its java api, I want to search documents with polygon geo filter(the polygon is rectangle usually),but when the polygon across the dateline (International Date Line,or 180 and -180 longitude),it go wrong. For example:
My code:
BoolQueryBuilder mustQuery = QueryBuilders.boolQuery().must(QueryBuilders.matchAllQuery());
......
GeoPolygonQueryBuilder qb = QueryBuilders.geoPolygonQuery("description.device_location.es_geo");
qb.addPoint(0,100);//the left down vertex of the polygon(rectangle),patams is (lat , lon)
qb.addPoint(0,-170);//right down
qb.addPoint(80,-170);//right up
qb.addPoint(80,100);//left up
qb.addPoint(0,100);//left down,same to the first vertex
mustQuery = mustQuery.must(qb);
SearchResponse searchResponse = EsClient.getClient().prepareSearch(Config.indexName)
.setTypes(Config.typeName)
.setSearchType(SearchType.DFS_QUERY_THEN_FETCH)
.setQuery(mustQuery)
.setFrom(0).setSize(size).setExplain(true)
.execute()
.actionGet();
diagrammatic sketch:
I want search in A areaļ¼but ES search in B area in fact
As the picture above, I provide ES points [0,100],[0,-170],[80,-170],[80,100],[0,100] to describe A area,and I want docs in A area, A area across dteline.
But according to the result, there is longitude 82,98,-121 etc., but no docs between [100,180]and between [-180,-170],so I suppose ES search in B area in fact(It analyze the polygon in error).
I search for the solution , on the ES's website, I found some words about this problem:
(form www.elastic.co/guide/en/elasticsearch/reference/2.1/geo-shape.html)
IMPORTANT NOTE: GeoJSON does not mandate a specific order for vertices thus ambiguous polygons around the dateline and poles are possible. To alleviate ambiguity the Open Geospatial Consortium (OGC) Simple Feature Access specification defines the following vertex ordering:
Outer Ring - Counterclockwise
Inner Ring(s) / Holes - Clockwise
For polygons that do not cross the dateline, vertex order will not matter in Elasticsearch. For polygons that do cross the dateline, Elasticsearch requires vertex ordering to comply with the OGC specification. Otherwise, an unintended polygon may be created and unexpected query/filter results will be returned.
The following provides an example of an ambiguous polygon. Elasticsearch will apply OGC standards to eliminate ambiguity resulting in a polygon that crosses the dateline.
But this is for geo-Shape datatype, and my docs' location is geo-point, I can't found similar words on geo-points's webpage(www.elastic.co/guide/en/elasticsearch/reference/2.1/geo-point.html).
I hava try some way:
1. Counterclockwise and clockwise vertex order;
2. start from every vertex of rectangle;
3. replace -170 lon with 190 lon;
but these ways all don't work.
Does anyone know how to search with a polygon across dateline ?
Thanks!
(sorry, I'm a Chinese developer and I can't speak English well, if there is solecism,please give me advice or comments, thank you.)
Here is the translated text of Chinese.Chinese characters couldn't be insert to question direct.
I'm the asker, and I have an answer already.
I have ask this question at https://discuss.elastic.co/t/search-geo-point-with-polygon-across-dateline/39103/3 ,and get answer there.
Before,I have ever think if there isn't perfect solution,I can split the polygon into 2 by dateline.I have know ES don't suport to search geo-point with polygon across dateline now:
At the moment geo_polygon queries for geo_point types do not work
across the dateline. You will either have to:
manually split the polygon into 2 and combine them using a boolean AND;
reindex the geo_points as geo_shapes (recommend setting points_only = true) and using a geo_shape (www.elastic.co/guide/en/elasticsearch/reference/2.1/geo-shape.html) query.
But if you know the polygon is a
rectangle, you can use a geo_bounding_box (www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-geo-bounding-box-query.html) query which will properly
handle the dateline (as in your example).
Thanks for #nknize and #medcl1 (at discuss.elastic.co)!
I am working on a application that is filtering a point cloud from a laser distance measuring device. Its a small array only 3x176x132 and Im trying to find parts inside a bin and pick the top most. So far I have played around with filtering the data into a way that can be processed by more traditional vision algorithms. I have been using the Sobel operator on the distance data and normalizing it and this is what I came up with
The Same filter applied to the PMD amplitude
My problem is I feel like I am not getting enough out of the distance data. When I probe the actual height values I see a drop the thickness of a part around the edges but this is not reflected in the results. I think it has to do with the fact that the largest distance changes in the image are 800mm and a part is only 10mm but Im sure there must be a better way to filter this.
Any suggestions