Tags » PostGIS

How to make a great-circle linestring

The postGIS GEOGRAPHY type connects two points on the Earth’s surface by the shortest route (the great-circle line). Unfortunately when displayed in Quantum GIS, this will appear as the shortest route between two points in map-space (actually a… 47 more words


How to name your road

In Motorway or motornay? I coloured UK roads by the first number in their name. To make the nomenclature clearer I have grouped these roads into regions, then coloured the map below. 114 more words

Ordnance Survey

KNN with FLANN and laspy, a starting place

FLANN is Fast Library for Approximate Nearest Neighbors, which is a purportedly wicked fast nearest neighbor library for comparing multi-dimensional points. I only say purportedly, as I haven’t verified, but I assume this to be quite true. 502 more words


Drivetime analyses, pgRouting

We’ve got some quick and dirty pgRouting-based code up on github. I say quick and dirty because it directly references the table names in both of the functions. 410 more words


Importing Large Spatial Datasets into PostGIS

Is PostgreSQL/PostGIS suitable for Big Data? This is a question I have been asking myself for a while, and I now have the opportunity to test it with a PostgreSQL instance from Amazon Web Services (AWS); after all, if such a service… 1,015 more words


Installing Postgres and PostGIS on Centos 6.5

I had some issues with my install from the original instructions on the postGIS site. What follows is a fix that worked for me.

My install was performed with guidance from the… 142 more words

PostgreSQL Database Application

Hi Chuck,

I am researching online mapping services for a class project and found this:

National Wild Fish Health Survey Database.


It runs on PostgreSQL. 217 more words

Geospatial Data