Sample chapter from ArcPy and ArcGIS: Second Edition

In celebration of GIS Day 2017, I’m sharing Chapter 13 from my new book, ArcPy and ArcGIS: Second Edition. Download the chapter here. The accompanying code is available here.

This chapter, Python and ArcGIS Enterprise, explores how to create an enterprise GIS workflow using ArcPy. This takes you from downloading web GIS data using ArcREST, to data editing on an enterprise geodatabase and publishing the data using ArcPy.

Find the whole book here, and enjoy your GIS Day!!!

Geospatial for Python 3

After the fun of completing ArcPy and ArcGIS: Second Edition, I’m pleased to announce that I am working on a new book for Packt Publishing: Geospatial for Python 3.

Python 3 has become mature and is supported by all major modules written to process and analyze geospatial data. To celebrate the maturation of Python 3, Geospatial for Python 3 will be written specifically to highlight how to use Python 3 as a GIS professional.

This wide-ranging book will cover open-source and commercial geospatial technologies, all of which have Python bindings or are written in pure Python. From GeoDjango to GeoPandas to spatial SQL & geodatabases, and even machine learning, this new book will introduce and explore all kinds of ways to perform analysis and create data insights.

I’m pleased to be joined in this effort by two experience GIS professionals with books to their name. Paul Crickard, author of Leaflet.js Essentials, is a GIS expert located in New Mexico. Eric Van Rees is an educator, writer, and analyst located in Spain. He has written trainings and articles about GIS for years; check out his writings here.

This book is slated for release in late February, 2018. I’m excited about this new effort and look forward to announcing its official release. I will be releasing sample chapters here as we get closer to publication.

Published: Arcpy and ArcGIS, Second Edition

Hot off the presses, the new version of ArcPy and ArcGIS is available now from Packt and Amazon and many others.

With six new chapters (in the e-book; five in print), this book covers the use of three Python modules for ArcGIS: ArcPy, ArcREST, and ArcGIS API for Python. Script samples and lessons show how to automate the analysis, management, publication and updating of geospatial data.

Dara O’Beirne and I worked hard to revise and update the existing book, while expanding and improving the coverage of Python modules for ArcGIS for Desktop, ArcGIS Online, and ArcGIS Enterprise.

I believe that this book is the most up to date Python book for ArcGIS. I hope you enjoy learning how to become an ArcPy powerhouse!



ArcPy course at the GIS Education Center for CCSF

I’m excited to announce that I will once again be teaching the Python for ArcGIS course for the GIS Education Center at City College of San Francisco.

Early birds get a 30 percent discount so please sign up early, but even late-sign ups will be pleased with the low cost of the 4 week/4 session course, which will cover chapters from ArcPy and ArcGIS.  I will also be introducing some material from the second edition of ArcPy and ArcGIS, which is underway and will be out in May,

I’m excited to meet more professionals and students who want to learn how to automate the analysis of location information. Contact me to discuss more about the class and the material!


  • by Silas Toms, President of Loki Intelligent Corporation



GIS Day 2016


I had the pleasure of speaking (remotely) to students at my alma mater, Humboldt State University. It meant a lot that the students asked if I could attend, or at least appear, and I was excited to speak to them.

Earlier in the year, I went to HSU to speak in person to these same students. I wanted them to know that geography and GIS are great topics to learn, and that there are a lot of jobs with companies large and small in the Bay Area and beyond. It was important for them to hear about how location information (or loki) has become a major industry, as not enough people know about it- yet.

Thanks so much to Professor Amy Rock and to student organizer Eric Daniels for having me speak!

Recognized by the White House

The award-winning common operational picture used at Levi’s Stadium was recognized by the White House for the unique collaboration between local, state, and federal governments it allowed.

This sentence in particular made me very proud:

“For the first time, law enforcement, NFL security, transit authority, and city leaders will have access to the same real-time security data in a consolidated visual platform. ”


Special Achievement in GIS Award, Esri UC 2015

I was proud to get the opportunity to met Jack Dangermond, President of Esri, and to receive recognition for the role I played in designing the Levi’s Stadium Common Operational Picture (COP) for the Santa Clara Police Department. I’m pictured with Sgt.  Ray Carreira (right) of the SCPD and my friend and co-designer, Gabriel Paun of Arini Geographics.

My first handshake with a billionaire, I believe.

Raising one finger in recognition of the life saved by SCPD while using the real-time COP at Levi’s Stadium.