PostGIS is a spatial database extender for PostgreSQL object-relational database. It adds support for geographic objects allowing location queries to be run in SQL.
FROM city, superhero
WHERE ST_Contains(city.geom, superhero.geom)
AND city.name = 'Gotham';
In addition to basic location awareness, PostGIS offers many features rarely found in other competing spatial databases such as Oracle Locator/Spatial and SQL Server. Refer to PostGIS Feature List for more details.
The last couple weeks have seen two interesting updates in the world of PostgreSQL “foreign data wrappers” (FDW). Foreign data wrappers allow you to access remote data inside your database, exactly like other tables. PostgreSQL ships with two example implementations, one for accessing text files, and the other for accessing remote PostgreSQL servers.
The two updates of interest to PostGIS users are:
Now you can access your PostGIS data without even going to the trouble of importing it first!
The 2.1.5 release of PostGIS is now available.
The PostGIS development team is happy to release patch for PostGIS 2.1, the 2.1.5 release. As befits a patch release, the focus is on bugs, breakages, and performance issues
The 2.1.4 release of PostGIS is now available.
The PostGIS development team is happy to release patch for PostGIS 2.1, the 2.1.4 release. As befits a patch release, the focus is on bugs, breakages, and performance issues
It has come to our attention that the PostGIS Raster support may give more privileges to users than an administrator is willing to grant. These include reading files from the filesystem and opening connections to network hosts.
PostGIS raster has so so many functions and probably at least 10 ways of doing something some much much slower than others. Suppose
you have a raster, or you have a raster area of interest — say elevation raster for example, and you want to know the distinct pixel values in the area.
The temptation is to reach for
ST_Value function in raster, but there is a much much more efficient function to use, and that is the
ST_ValueCount function is one of many statistical raster functions available with PostGIS 2.0+. It is a set returning function that returns 2 values for each row: a pixel value (value), and a count of pixels (count) in the raster that have that value. It also has variants that allow you to filter for certain pixel values.
This tip was prompted by the question on stackexchange How can I extract all distinct values from a PostGIS Raster?
The Institut Géographique National (IGN) is the national mapping agency for France, with 1800 employees and a mandate to collect, integrate, manage and distribute reference geographical information for the whole country.
Infoterra has been in the geospatial business for over 25 years, since its founding in 1980 as the UK National Remote Sensing Centre. In that time, NRSC grew, formed international partnerships with space agencies, expanded into aerial data collection, and was eventually privatized and re-named “Infoterra” in the late 1990s.