How I used SQL to generate an accumulated sum of spatial data My friend Tomas does work with business analytics, and wanted to find a way...

A friend recently asked me to help him generate polyline shapefiles with Z and M values that he could deliver to a customer.  The problem...

As most of you know, I am a big fan of spatial SQL.  It is my go-to tool whenever working with GIS.  But, I have seen too many people...

My good friend Stuart Hamilton gave me a fun conundrum to try out. He has a file of province boundaries (400 areas) and lidar derived...

I have two new books out – How do I do that in PostGIS, and How do I do that in Manifold SQL. From the back cover of How do I do that in...

In previous posts, I showed how to create ARC/INFO functions in SQL using Manifold 8.  While I love SQL, it is somewhat frustrating to...

In addition to SQL, I also am interested in processing large volumes of spatial data.  One of the newest rages in “big data” is Hadoop....

In our book we illustrated the use of quadrat analysis for determining whether points were random, clustered, or distributed.  Figure...

It is nice to get back to the book, and start talking about Statistical Problem Solving in Geography again.  Today we are going to look...

Dale posted a request to see Line Density recreated in SQL.  Please take a look at the ESRI help topic for line density. I will warn you,...

I was recently asked by danb to illustrate the ARC/INFO function symmetrical difference. We basically want to find those areas in layer A...

We are going to conclude our overlay posts with the ARC/INFO UNION command.  This should be a lot easier than it actually is.  I think...

The ARC/INFO IDENTITY operation seen here is sometimes confusing because it takes ALL of the Input feature, and the part of the IDENTITY...

I promised you that I would address the attributes.  Remember, our previous query only performed the ClipSubract for the geometries, and...

Today we are beginning another four-part session on the classical ESRI topological overlay functions of Erase, Intersect, Identity, and...

We’ve spent some time looking at how to create spatial interaction models using PIVOT tables and spatial constructs in SQL.  The one last...

We recently looked at spatial interaction in the form of inverse distance weighting.  However, some spatial interaction matrices are...

In my book Introduction to Statistical Problem Solving in Geography, we talk about relationships among geographic objects. These...

Every geographer knows Tobler’s Law.  Near things are more similar to things that are far away.  From this, we often begin our...