Questions tagged [spatial-index]

In a database, a mechanism for optimizing access to data based on the spatial column(s) of a data table.

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Double indexing and looping over raster lists in R

I have a list of 63 rasters. They are the same extent, resolution, projection, etc. Because I extended 62 rasters to the maximum extent of the 63rd, I introduced NA values. However, these are relative ...
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Which collection data is suitable for calculating soil moisture index using Landsat 8?

I am trying to compute soil moisture index using Landsat 8 collection 1 level 1, but it seems that I am not computing it properly. My range is not 0 to 1, as it should. Values of my variables can be ...
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How to create a spatial index in a GeoPackage with GeoTools?

I want to write a GeoPackage file with GeoTools and create a spatial index in the end. After consulting the documentation and also the implementation I still can not figure out a way to do this using ...
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Shannon diversity index in ArcGIS Pro

As my data sets are very large I’ve been unable to compute anything in R. I’ve been successful doing things manually in ArcGIS Pro. Now I’m attempting to calculate the Shannon diversity index for ...
3 votes
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How to create a GIST index on locations within a JSONB array column?

I have a JSONB column with an array of locations. I want to do a Postgis GiST index on each of the array items. For example: [{ "location":{ "type": "Point", ...
3 votes
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Does GeoPandas generate a PostGIS spatial index automatically?

It is easy to save a GeoPandas dataframe to a PostGIS database using the gdf.to_postgis(...) command. But, it is not clear to me if it automatically generates spatial indices or if these need to be ...
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1 answer
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Same Spatial Query on nodes table gives different read time

I have created 2 databases. First one has PGSnapshot Schema which looks like this. On this I fire query select id,ST_AsText(geom) from nodes where ST_Intersects(geom , ST_GeomFromText('POLYGON ((-...
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Extending pyrtree to return input index of each matched bounding box

After some effort I finally got a working version (on Python 3.9) of pyrtree by merging a couple PRs onto my fork of the original repo. You can see the code here: Lightly updated version of pyrtree ...
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3 votes
2 answers
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Finding nearest polygon in PyQGIS using QgsSpatialIndex

I am trying to write a custom processing tool for QGIS which joins the nearest attributes with some conditions. Therefore I'd like to use a QgsSpatialIndex to increase performance. This works ...
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1 vote
0 answers
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Get map to use function-based spatial index (ST_GEOMETRY)

SDE.ST_GEOMETRY — Oracle 18c — ArcMap/EGDB 10.7.1: I have a view that returns the startpoint of lines as an ST_GEOMETRY column: create or replace view bc_atn_startpoint_vw as ( select objectid, ...
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GeoPandas spatial index - passing RTree parameters to index

I am quite familiar how to work with the Toblerity RTree library: import fiona import rtree with fiona.open(input_path,'r') as source: p = rtree.index.Property() p.filename = "index....
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Spatial indexes with RTree for polygons

I am trying to understand about how R-tree works for polygon data. In other words, polygon is a list of vertices (points), however, I am wondering how spatial index can recognize the order of points ...
3 votes
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Set a spatial index on a set of rows (without table) in PostGIS

I got a giant geometry that I retrieve from an API and I break it into smaller pieces with ST_Subdivide. Right after, I'm inserting it into a temporary table (which is indexed and only contains a ...
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Producing Shadow Indexes in Google Earth Engine using maximum values from a ImageCollection

I'm trying to generate a Shadow Index using the maximum values from a image composite (ImageCollection). Here is the link with the code: https://code.earthengine.google.com/...
6 votes
1 answer
616 views

Actual PostGIS query execution time MUCH slower than expected

I've run into a performance problem from which I'm not sure how to move forward. I have a table with ~150M rows. And I have a query that in EXPLAIN has a cost of just cost=0.55..209.36, but in EXPLAIN ...
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1 vote
1 answer
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Getting index of special pixel (x and y position) or transform lat/lon of pixel to index in Google Earth Engine

I am trying to find the index (x and y pixel position in an image) of a pixel (ex: the pixel with max DN value). however, it has been challenging for me. My code is: var geometry3 = ee.Geometry....
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1 answer
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How to speed up PyQGIS code for finding intersection of features in the same layer

I an deleting one of the intersecting polygons from a vector layer using PyQGIS code mentioned below. It is too slow as I have many features in the layer. Is there a way to speed it up? index= ...
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1 answer
466 views

Adding multiple Image using Google Earth Engine

I want to make NDBI indices to a certain location. But when I run the code it can only show part of it //####################### Import SHP ####################### var countries = Indonesia //Import ...
3 votes
0 answers
315 views

How do I use spatial index to speed up a model?

I want to process data with a model in QGIS. It works fine, but the bigger the datasets get, the longer it takes. The reason is, I use GeoJSON layers and they don't have a spatial index. That is why I ...
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1 vote
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Optimized query to find nearby locations

I am working with the GeoNames database which has around 10 million rows of locations including longitude and latitude. I have tested around 6 various nearby location queries including spatial indexes....
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4 votes
1 answer
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Parallelization of rtree index

Is it possible to share rtree index in memory with multiple processes? I have succeeded to use rtree in multiprocessing environment with joblib, but the problem is that each process has its own copy ...
4 votes
1 answer
194 views

Choosing appropriate index for PostGIS data

I have been reading this blog by Paul Ramsey, and considering my own data. https://blog.crunchydata.com/blog/the-many-spatial-indexes-of-postgis I have a regular grid covering an area of the world. ...
1 vote
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264 views

Understanding Rasterio index coordinates

So I read in a .tif image with rasterio and what I get out when printing dataset.read(1) is what I understood a coordinate system in the "red" band of the image. The coordinate system is in ...
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Index‐Based Built‐up Index (IBI) no in the specified range

I'm trying to calculate Index‐Based Built‐up Index (IBI). This index has been mentioned in A new index for delineating built‐up land features in satellite imagery. As mentioned in the paper, the range ...
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(QGIS 3.20) Adding features while spatial index is created makes them disappear

I am encountering a weird behaviour in QGIS 3.20 on Windows. Steps to reproduce: Create an empty project Create a SHP layer. Add a few features. Save the changes to disk At this point everything is ...
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5 votes
1 answer
258 views

Is a spatial index on a ST_Transformed geometry simply ignored when the transformation has the same target CRS than CRS of the geometry?

I have such vanilla index on a PostGIS table: CREATE INDEX polygons_gix ON public.polygons USING gist (geom); Because of this: If using more than one transformation, it is useful to have a ...
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7 votes
3 answers
864 views

Optimizing an intersection between a single massive multipolygon (WKT) and many features from PostGIS

Context I have a massive MultiPolygon (~90'000 vertices, super complex, spreading over 60km², with lots of holes and parts) resulting of some Python computation. This MultiPolygon is coming as a WKT ...
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2 votes
1 answer
439 views

How to use spatial indexes in SQL queries made on geopackages

I'm trying to learn how to write geopackage SQL queries so that the r tree index is used, but I can't seem to find any good information. I'm just trying to write a simple query in the qgis db manager ...
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3 votes
1 answer
870 views

PostGIS: Does re-creating a spatial index after inserts or updates affect performance?

Creating a spatial index on a geometry field is very important. The docs also state that you should perform a VACUUM ANALYZE after large update operations. But is it ever necessary to drop an existing ...
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2 votes
1 answer
740 views

GEE- Calculating Burned Area Index for Sentinel 2 (Filipponi et al. 2018) but getting binary result than index range

I am trying to calculate BAIS2 index for sentinel-2 collection over a study area in Google Earth Engine. I tried to create a function using expression but end result is binary image rather than index ...
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2 votes
1 answer
122 views

Grab/Index the raster bands before and after a unique band for each pixel (depth-wise) in a raster stack

I'm working with a time series stack of 28 raster bands. Each band is an image for a specific date, spanning all of the year 2020, and they are stacked in order. The stack (change_point_raster) is in ...
3 votes
0 answers
179 views

BRIN Index on PostGIS Geography

I have about 1.5 billion points in a geography column which represent topography. I'll be retrieving all the points that are within a certain distance of a given long/lat. I was able to create a GIST ...
4 votes
1 answer
312 views

Selecting features that intersect features of another polygon with spatial index

Based on the answer of @mgri here: https://gis.stackexchange.com/a/224954/164953 I tried to select the features of a multilines layer intersecting less or more than 2 features of a multipoints layer. ...
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2 votes
1 answer
162 views

PostgreSQL/PostGIS KNN query using <-> operator in ORDER BY clause not using index

I am trying to set up a KNN query using the <-> operator in the ORDER BY clause and the query planner does not appear to be using the spatial index as expected. I am not using bleeding edge ...
2 votes
1 answer
406 views

Creating indexes with PostGIS using all CPU cores

I have to run a whole bunch of GIST index creation, on some tables containing lots of records (scale of many countries, OSM data): CREATE INDEX CONCURRENTLY IF NOT EXISTS osm_footways_gist ON ...
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Creating Quadtree/Space Filling Curve Index atop GeoTiFF

I'm a complete beginner in GeoTiFF manipulation. I'd like to get some help in possible Java/Python/Scala project which performs spatial indexing (Quadtree, Space Filling Curves) atop given image(s). I ...
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4 votes
2 answers
409 views

PostGIS- slow spatial UPDATE queries on 50mil rows

PostgreSQL 11.8, AWS hosted RDS instance, SSD, 8GB RAM, 3.0 GHz Intel Scalable Processor. Plenty of storage space. I'm finding running updates on a large table using spatial queries is taking a very ...
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1 vote
1 answer
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Optimising PostGIS ST_DWithin across many tables for existence only

I have 13 tables containing MultiPolygons in the same projection (27700). I am trying to write an efficient query to get back a Boolean for: Is one polygon in table A within X meters of any polygon in ...
0 votes
1 answer
153 views

Can the QGIS spatial index be used to evaluate points contained in multiple polygons of shapefile layers using PyQGis?

I want to use the spatial index of QGIS to improve the performance in the spatial query of multiple points in multiple polygons, both are shapefiles, but has not given me good results in execution ...
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1 vote
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Using spatial indexes on point to polygon intersection query in SQL Server

I have a table (tab_point) with about 5 million points and another table with a few thousand polygons (tab_polyg). I need to find what points intersect with what polygon (to establish a count of ...
0 votes
1 answer
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ST_GEOMETRY: spatial column must appear immediately after spatial relationship function for spatial index to be used

The docs for SDE.ST_GEOMETRY have a blurb that says the following: When are spatial indexes used with ST_Geometry? ...the spatial column must appear immediately after the spatial relationship ...
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1 answer
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What is name of dataset in GEE to estimate level of urbanization for each county (district) in a country /region?

I am epidemiologist, not remote sensing expert. I am interested to find association between disease incidence /reported cases with urbanization (hypothesis " more bigger cities , more incidence&...
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Postgresql POSTGIS not using index field while having GIST index on geometry field [duplicate]

I have around 2M rows on my PostgreSQL table with GIST index on geo_point field but while I try to use ST_Distance or ST_DWithin it is not using the index instead it is doing Parallel Seq Indexed ...
1 vote
0 answers
343 views

PostGIS: Speed up intersect by filtering first

I have a table with 20 million polygons where queries take some time (with an gist index on the geometries). I thought I could speed up the queries by first filtering on an additional id (selectivity: ...
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2 votes
1 answer
197 views

Function-based spatial index: Use sdo_geometry() constructor instead of custom function?

I have an Oracle 18c table that has XY columns, but not a SHAPE column. I've created a query on the table that dynamically generates an sdo_geometry SHAPE column. sdo_geometry(2001, 26917, ...
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1 answer
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Determining area size of grid (reference grid) in ArcMap [closed]

How do I determine the area size (square kilometres) of a customised reference grid in ArcMap 10.7? I have tried Data Driven Pages and it is not working for me. The idea is to know the area size of ...
15 votes
2 answers
693 views

When not to create spatial index?

As I realized once again connected with this answer to Joining attributes by location using QGIS, creating a spatial index can result in huge performance improvements. However, I was wondering why ...
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0 votes
0 answers
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Spatial indexing of GeoTIFF images (Java Library)

I have a requirement to spatially index each pixel of GeoTIFF images and store them in a scalable database. I intend to perform this in the following manner. Divide each GeoTIFF into smaller tile ...
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515 views

Spatial Index warning from Spatial Query

I'm trying a spatial query using QGIS version 3.10 using a buffer layer and a set of species records. I wish to know how many species records fall within the buffer. When I perform the spatial query ...
1 vote
1 answer
116 views

Improving PyQGIS distance matrix efficiency

I have written a custom processing tool, which I use within a large graphical model in QGIS. I am looking for a way to speed it up. First step of this processing tool is to connect every point of one ...
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