If you are like me, you love writing spatial SQL. But what can you do if you have a geodatabase, some shapefiles, or any other data...

A friend recently asked me about the cool looking bivariate maps produced with ArcOnline, lamenting that the capability seemed lacking...

A friend is doing some research on estrogen and estrodial in water samples in Delaware. We have about 50 sub-watersheds that show the...

I wanted to revisit the taxi data example that I previously blogged about.  I had a 6GB file of 16 million taxi pickup locations and 260...

Do you have a set of lines that you need to determine if there are any “dangle” nodes?  A dangle is a line segment that overhangs another...

I was interested in creating mult-ring buffers but with a twist: I didn’t want the buffers to overlap one another.  In other words, if I...

She also has an innate ability to work with GIS, and pick up new things: one day she has never programmed in Python, and the next day,...

The Web GIS Duel: Final Thoughts This is a continuation of Mark Balwanz’s blog posts on his creation of web mapping sites using both ESRI...

#TUgis2017) is on March 20/21, 2017.  I first attended TUgis in 1990, and it is always a great conference.  It is not too large, so it is...

I’ve always been proud of our Salisbury University GIS students, and love to push them as far as their little minds can handle it.  You...

Today my students got to present some of their work at the Maryland Geographic Information Committee Quarterly meeting.  On Monday we...

Once again, I am continuing my role as a mentor in a National Science Foundation (NSF) Research Experience for Undergraduate program....

CLICK TO VIEW Jeff Scarmazzi presenting on h0w to create editing rules and triggers using Postgres and PostGIS Today I want to introduce...

The Open Source Implementation This is a continuation of Mark Balwanz’s blog posts on his creation of web mapping sites using both ESRI...

UMD provided me with enrollment numbers, and we are getting a pretty full class.  However, a few people on the “outside” have asked for a...

I am putting up a new course on udemy.com about learning GDAL – and, it is going to be FREE.  I’ve been so happy with the uptake and...

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...