New answers tagged spatial-index
Yes. It does as it appears from looking at the source code for the Spatialite Data Provider. The QgsSpatiaLiteFeatureIterator class is the one that supplies the features to the map upon sending a rectangle extent. You can just search for 'spatialIndex' in that class to see they actually use the index if available.
I just went through a week of back-and-forth with ESRI Tech Support about this issue. I have found two parameters in the Defaults Keyword in the dbtune table: Parameter: A_MS_SPINDEX; Value: "GRIDS = (MEDIUM, MEDIUM, MEDIUM, MEDIUM), CELLS_PER_OBJECT = 16" Parameter: B_MS_SPINDEX; Value: "GRIDS = (MEDIUM, MEDIUM, MEDIUM, MEDIUM), CELLS_PER_OBJECT = 16" ...
You can also use: the Python module PySAL: Spatial Autocorrelation. You can use it in the Python console of QGIS or in a script in the Processing Toolbox R (Applied Spatial Data Analysis with R: analysis with R, “The Problem of Spatial Autocorrelation:” forty years on, Geary's C test for spatial autocorrelation, for example, but there are many others) ...
You might want to take a look at this question (How to implement Spatial Autocorrelation using QGIS or PostgreSQL (or any free application)?) and look at programmatic solutions like R. QGIS may be another option as well. This website outlines different formulas and measures for spatial autocorrelation that may also be of interest to you
There's two things going on here: the GIST API in PostgreSQL and the bindings of types to that API for the purposes of building an R-Tree. PostGIS necessarily uses the PostgreSQL GIST API. That's what it's for. That way we don't have to worry about transaction management or writing things to disk or all the other messy important things involved in ...
In the PostGIS documentation it says: PostgreSQL supports three kinds of indexes by default: B-Tree indexes, R-Tree indexes, and GiST indexes. ... GiST (Generalized Search Trees) indexes break up data into "things to one side", "things which overlap", "things which are inside" and can be used on a wide range of data-types, including GIS ...
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