Tags » PostGIS

The Northwest Bushwick Community Map Redesign

The Northwest Bushwick Community Map is meant to be a resource for local community organizations and tenants rights groups to easily access disparate information around land use, housing and urban development for the neighborhood of… 559 more words

Interactive Cartography

The North-South divide (according to population density)

All Englishmen have an opinion on where The North starts (and how to get there, which service stations to stop at on the way and why you shouldn’t be going in the first place). 64 more words

PostGIS

Postgis plpgsql function that generates an arbitrary number of random points

The following plpgsql function, stolen together from various places over the internet generates an arbitrary number of random points within a rectangle. Great if you need test data. 114 more words

A new QGIS tool (based on ogr2ogr) to import vectors in PostGIS, the fast way

In QGIS there are many tools that can be used to import vectors inside a PostGIS database, each one has pros and cons:

  • SPIT core plugin: available since long ago but now seems to be a unmaintained tool and therefore will be probably removed in a future QGIS release.
  • 528 more words
QGIS

Functions in Postgis for generating grids.

The following is a modification of the CreatFishNet() function proposed in the thread of gis.stackexchange

The difference is that I’m using an index (called gid) which can be used as a primary key and instead of using geometric types I’m using geography. 125 more words

Postgis

Using geography types in POSTGIS

Why do someone has to bother in choosing either geometry or geographic types (columns) in Postgis or any other geospatial database?

The answer for this is a geometrical reason. 415 more words

Postgis

points to line (postgis)

My first query should be the “snap points to lines” problem.

select
#unique ID for each row
row_number() over (order by points.gid) as gid,
#ID from points… 276 more words

Qgis