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 masthead says “no opinions – just code”, but I have to give one quick opinion of my daughter: she graduates college tomorrow and I am...

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...

Over the next week I am going to illustrate how to create the ESRI ARC/INFO commands of ERASE, INTERSECT, IDENTITY, and UNION (for you...

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...

Today I am cheating a little. In the last post, we created a symmetrical distance matrix using strict distances between 6 cities.  I...

Today I am at #delmarvagis. One of my other hats at Salisbury University is that of the Technical Director of the Eastern Shore Regional...

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...

I wrote a paper in 2006 about using SQL for the Modifiable Area Unit Problem (MAUP).  The example was an agricultural experiment field,...

OK, I admit it, this post really isn’t about “spatial”.  It’s more about descriptive statistics, but I wanted to introduce the ability to...

In our last post, we looked at a simple random point distribution.As you recall from my book, a single random sample may in fact not be...

This post is part of a series entitled Spatial is not Special, where I will illustrate how spatial constructs in SQL provide us with a...

I love the Tabulate Area command in ArcGIS.  The ability to create a cross tabulation of two feature datasets is very cool.  SQL has...

I can’t help myself, once I get started writing SQL, I always go on tangents, because its so cool to try out new things.  In our last...