Subscribe: Boston GIS Articles and Tutorials
http://www.bostongis.com/GISRss.aspx
Preview: Boston GIS Articles and Tutorials

Boston GIS Articles and Tutorials



Features the latest GIS tutorials on postgis, mapserver and other GIS technologies



 



Part 1: Getting Started With PostGIS: An almost Idiot's Guide (PostGIS 2.2)

2015-10-12

What Is PostGIS?

PostGIS is an open source, freely available, and fairly OGC compliant spatial database extender for the PostgreSQL Database Management System. In a nutshell it adds spatial functions such as distance, area, union




pgRouting: Loading OpenStreetMap with Osm2Po and route querying

2013-04-11

For this exercise we are going to demonstrate how to use OSM2PO and an OSM pbf to create a routing network. Much of this is borrowed from Anita Graser's tutorial O




Part 1: Getting Started With PostGIS: An almost Idiot's Guide (PostGIS 2.0)

2012-05-12

What Is PostGIS?

PostGIS is an open source, freely available, and fairly OGC compliant spatial database extender for the PostgreSQL Database Management System. In a nutshell it adds spatial functions such as distance, area, union




Part 3: Using your own custom built OSM tiles in OpenLayers

2011-06-19

In this third Part of our OpenStreetMap series we will demonstrate how to use the osm tiles we built in Part 2: Building Tiles with PostGIS OpenStreetMap data.

<



Part 2: Building Tiles with PostGIS OpenStreetMap data and Mapnik: Your Own OpenStreetMap

2011-05-19

This is a continuation of our Loading OpenStreetMap data in PostGIS. In this tutorial we will build a tile cache of the Massachusetts data we loaded in Part 1 and then




Part 1: Loading OpenStreetMap data into PostGIS: An Almost Idiot's Guide

2011-05-15

For this exercise, we will download Massachusetts OSM data and then load it into our PostGIS spatially enabled PostgreSQL database. The OSM data contains roads, points of interests, building footprints, administrative boundaries, addresses, and too man




PostGIS Concave Hull

2010-06-04

This is a work in progress, and demonstrates the ST_ConcaveHull function that will be available in PostGIS 2.0. The basic approach is that it first creates a convexhull of the geometry and then uses the ST_Clo




OSCON 2009: Tips and Tricks for Writing PostGIS Spatial Queries

2009-07-30

We gave a presentation on writing PostGIS spatial queries at OSCon 2009 last week. Slides will be available on the site, but you can download them PGCon2009: PostGIS 1.4, PostgreSQL 8.4 Spatial Analysis Queries, Building Geometries, Open Jump

2009-05-23

We gave a lecture at PGCon 2009. Below are the links and the generated data set. Some of the examples use features in PostgreSQL 8.4 and PostGIS 1.4, but most should be applicable to earlier versions. The data generation part does use PostgreSQL 8.4




Part 1: Getting Started with SpatiaLite: An almost Idiot's Guide

2009-03-28

What is SpatiaLite?

SpatiaLite is an SQLite database engine with Spatial functions added. You can think of it as a spatial extender for SQLite database engine which is similar in concept to what PostGIS does for the PostgreSQL Object-Rel




Part 3: Getting Started With SQL Server 2008 Spatial: Spatial Aggregates and More

2008-11-11

No Aggregates, what's a girl to do?

Those who read our PostGIS series may be wondering why the examples we chose were not the same as what we did for PostGIS. Sadly SQL Server 2008 does not have any built-in spatial aggregates such as those




Part 2: Getting Started With SQL Server 2008 Spatial: Reproject data and More Spatial Queries

2008-11-05

Bringing in Towns As Geography (Geodetic) -- Continued

In the first part we covered bringing in Mass Towns data as Planar geometry, but were stuck because we need to transform the data to a degree based projection (in particular one listed in




Part 1: Getting Started With SQL Server 2008 Spatial: An almost Idiot's Guide

2008-10-31

What Is SQL Server 2008?

Microsoft SQL Server 2008 is the first version of SQL Server to have built-in functionality for doing geographic spatial queries.

This tutorial is similar to our PostGIS ST_Dump, Dump

2008-06-23

What is ST_Dump, Dump

ST_Dump is a function that takes a geometry and returns a set of Postgis geometry_dump structure. Geometry_dump is composed of 2 properties. geom and path. The geom is a geometry and path is a mu




PLR Part 3: PL/R and Geospatial Data Abstraction Library (GDAL) RGDAL

2008-03-14

What is GDAL and RGDAL?

GDAL stands for Geospatial Data Abstraction Library and is a popular open source GIS library originally developed and maintained by Frank Warmerdam with contributions




PostGIS: ST_Translate

2007-10-16

ST_Translate, Translate

The ST_Translate function takes any geometry (linestring, multiline etc) returns a new geometry that is the original geometry moved by a vector defined by X,Y,Z. Note the units of measurement are always in the units




Intersects Intersection: PostGIS - ST_Intersects, ST_Intersection

2007-09-21

ST_Intersects, Intersects

ST_Intersects is a function that takes two geometries and returns true if any part of those geometries is shared between the 2. In PostGIS versions before 1.3 you would use the following syntax to utilize indexes <




Summary (pre 1.3.1 name), ST_Summary (+1.3.1)

2007-08-24

ST_Summary(geometry) gives you a brief summary of a geometry telling you how many simple geometries, rings and type of geometry it is.

select ST_Summary(the_geom) from neighborhoods; Output of the above ran from psql looks like



PostGIS Nearest Neighbor: A Generic Solution - Much Faster than Previous Solution

2007-08-01

A generic solution to PostGIS nearest neighbor

After some heavy brainstorming, I have come up with a faster and more generic solution to calculating nearest neighbors than my previous solutions. For the gory details on how I arrived at this s




Solving the Nearest Neighbor Problem in PostGIS

2007-07-21

A common problem encountered in GIS is the Nearest Neighbor problem. In a nutshell the problem is to find the x number of nearest neighbors given a geometry and n geometries of data.

The nearest neighbor crops up in other disciplines as wel