How to create a rail query in PostGIS?

How to create a rail query in PostGIS?

I create a query in PostGIS using ‘where’ clause, and with that a table. now I want to use those attributes to create a intersection with other table… but I don’t know how to call the attributes, because is always asking for the original table and like that it will skip the query First query to get Rail features:

When to skip the St _ intersection call in PostGIS?

In many situations you know the intersection of 2 geometries without actually computing an intersection. In these cases, you can skip the costly ST_Intersection call. Cases like this: This kind of question comes up a lot: As discussed in stackexchange Acquiring ArcGIS speed in PostGIS

Why do you need PostGIS for spatial queries?

The raison d’etre of spatial databases is to perform queries inside the database which would ordinarily require desktop GIS functionality. Using PostGIS effectively requires knowing what spatial functions are available, how to use them in queries, and ensuring that appropriate indexes are in place to provide good performance.

Is there a St reclass function in PostGIS?

This raster question comes up quite a bit on PostGIS mailing lists and stack overflow and the best answer often involves the often forgotten ST_Reclass function that has existed since PostGIS 2.0.

Which is the best tool for bounding box in PostGIS?

You would have to box the relevant bits (say the Canadian and French components) separately. The best tool for this in PostGIS is the geometry accessor ST_GeometryN (geometry,int) (reference: http://postgis.refractions.net/docs/ST_GeometryN.html ).

When to use bounding box in a multipolygon?

This works fine for multipolygons containing only one polygon, but some rows have polygons very spread apart, hence the bounding box is not relevant when the multipolygon contains one polygon in Europe and one in Canada for example. So I would need a way to get one box2d per polygon per multipolygon, but I haven’t found how just yet.

When do you need a SRID in PostGIS?

The SRID is required when creating spatial objects for insertion into the database. Input/Output of these formats are available using the following interfaces: bytea WKB = ST_AsBinary(geometry); text WKT = ST_AsText(geometry); geometry = ST_GeomFromWKB(bytea WKB, SRID); geometry = ST_GeometryFromText(text WKT, SRID);

How to create a spatial table with PostGIS?

Creating spatial tables with PostGIS. In the PostGIS documentation it says that there are two steps to creating a spatial table with SQL: Create a normal non-spatial table. Add a spatial column to the table using the OpenGIS “AddGeometryColumn” function.

How does St _ intersection-PostGIS work in GEOS?

If the optional gridSize argument is provided, the inputs are snapped to a grid of the given size, and the result vertices are computed on that same grid. (Requires GEOS-3.9.0 or higher) Geography: For geography this is really a thin wrapper around the geometry implementation.

What are the functions of PostGIS in OGC SFS?

To make it easy to determine common spatial relationships, the OGC SFS defines a set of named spatial relationship predicates. PostGIS provides these as the functions ST_Contains, ST_Crosses, ST_Disjoint, ST_Equals, ST_Intersects, ST_Overlaps, ST_Touches, ST_Within.

https://www.youtube.com/watch?v=B9eEnjSiUAw