Tags » PostGIS

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


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


points to line (postgis)

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

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


getting Postgis to run (ubuntu 14.04)

I’m starting to learn postgis, too. Apparently, there a lot of data juggling can be done, too.


#install the packages

sudo apt-get install postgres postgis postgresql-9.3-postgis-scripts…

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NYC Property Data Extractor web app prototype

I refined the prototype for the NYC Property Extractor web app a bit more with some minor UI / UX changes. The app now only lets the user select an area when they are zoomed into the neighborhood scale (greater than or equal to zoom 16). 70 more words

Interactive Cartography

Airspace -- A deep rabbit hole

In previous maps we looked at Class B, C, and D airspace. Let’s add in Class E0 and E5… (not yet in 3D):

(Map tiles by… 33 more words


Airspace is complicated -- and so I abuse PostGIS once again -- Reprise...

In the previous post: http://smathermather.wordpress.com/2014/10/25/airspace-is-complicated-and-so-i-abuse-postgis-once-again/ we explore the 3D shape and complexity of controlled airspace.

Now here’s the rest of the code. We’ll add our affine transformation ala Seth Fitsimmons: 204 more words