Higher Dimensionality Cleanup
The support for dimensions higher than X/Y is uneven as currently implemented. Most operations support clean handling of the Z dimension. A reasonable number of important functions do not support handling of the M dimension.
For example, the ST_MakeLine function does not build output lines that include the higher dimensions on the input points. The ST_Intersection function does not retain M-values that are on the inputs.
In general, any function that uses the GEOS library for functions will lose M-values, as they are not carried into the library.
This work item will catalogue all functions and their handling of higher dimensions, will improve the GEOS library to carry M-values through operations, and will improve operations to not lose higher dimension values where it is possible to retain them through operations.
For some operations that create new geometries (ST_Buffer(), ST_ConvexHull()) retention of extra dimensions is problematic, but in general most functions should be able to handle higher dimensions cleanly.
Funding
This roadmap item is currently unfunded.
Add your support for this item by contacting us for a quote and discussion of the particular features you need.
Get a quote now!
Get a quote or read more about core development to add your support to a road-map item.
Other Roadmap Items
The support for dimensions higher than X/Y is uneven as currently implemented. Most operations support clean handling of the Z dimension (but a few do not). A reasonable number of important functions do not support handling of the M dimension. This item would fix functions not handling higher dimensions.
The PostGIS spatial index currently works exclusively in the X/Y plane. For data such as fleet tracking the “Z” or “time” dimension can serve as a useful query restriction. Higher dimensional indexes are needed.
The LRS functions in PostGIS are a mismatched combination of functions that operate on measures and functions that use length as a proxy to measure. A re-work to formalize the LRS handling is needed.