April 26th 2016 - SLUG Meeting DiGISt

The 28th Quarterly Salt Lake GIS Users Group (SLUG) meeting, held on April 26, 2016, from 11:30 am to 1:30 pm at Sandy City Hall.  There were about 65 in attendance.

This meeting was a brown-bagger; we did not have a lunch sponsor. If you have any contacts that would be willing to ‘sponsor’ a lunch by providing food/ drinks in exchange for their advertising at the meeting, contact Tom Toronto, SLUG Board member.


Tom Toronto, SLUG Board

·      The next SLUG meeting will be on Aug 10, 2016 at DNR in SLC. Hope you will be able to attend!

·      We are always in need of presenters. If you would like to present, or suggest someone who you’d like to see present, please contact Neal Fraser, SLUG Board member.

·      Has anyone had problems receiving SLUG emails?  There is an on-going tech issue between Mail Chimp and Gmail.

Dave Henrie, UGIC Board

Dave invited and encouraged everyone to attend the upcoming UGIC (Utah Geographic Information Council) conference in May at Bryce Canyon (see http://ugic.info/).



Addressing in Davis County

N. Jeffery Baker, Davis County GIS

Jeff talked about the many types of problems that can happen in address systems, and how best to spot them, using “Where’s Waldo” as a humorous theme.  He explained and showed several methods they use to identify problems.

These include: 

·      Using a Definition Query to find and display the pre-directions of address points in one quadrant (NSEW) at a time, any points that show up outside that quadrant are in error. 

·      Displaying address points using a color ramp (say, red to green) for the house numbers. (Just one axis at a time). For example, when examining N-S addresses, all points all the way across the map E-W have the same color. As you move North or south, points are shown in other colors.  Addresses with certain errors would have the wrong colors. 

·      Parity - formula to class all points as 0 or 1 for odd/even values.  Then color them by that value, to spot more easily those on the wrong side of the road.

·      The Fishbone model.  Uses two models to draw a line from every address point to the place it geocodes to on the centerlines. Errors show up as lines going to a wrong CL, or funny angles, or not having a line at all. Can help validate centerlines AND points at the same time.  TIP: When validating addresses, be sure to set all geocoders to use 100%.


Geography Humor Segment 

Ray Montgomery, SLUG Board

Ray showed a short video where people-on-the-street were asked three of the same questions as a class of children at a Geography Bee, cutting back and forth between the two. You can see most of the videos we’ve shown at SLUG meetings here: YouTube


Live to Ride, Ride to Kill

Brad Sorenson, Salt Lake City Mosquito Abatement District

Brad reported on the tremendous progress made in managing mosquito abatement efforts using their bicycle program and GIS. The SLC Abatement District was started in the 1920’s.  It covers 163 square miles, and is responsible to treat over 17,000 catch basins where mosquito's might reproduce.

Prior to the bike program, they were only able to treat about 800 sites per year.  The first year the bike program started, they made 26,550 treatments, some of the 17,000 more than once.  Now, the four-person bike team is treating all sites at least monthly. He explained how the program evolved from paper, through the old large GPS units to the current smaller GPS devices, utilizing GIS to create routes and track their progress.  They now use Collector for ArcGIS to easily and quickly document treatments done at each site. Additionally, they had to expand the types of treatment sites as new mosquito types arrive here. It is interesting that the treatments are performed using a bacteria harmful to the mosquito larvae, rather than toxic poisons.


Python Tips and Tricks for Automating Processes

Casey Sledge, Salt Lake County Recorder’s Office

Casey did some live Python programming.  He demonstrated several non-GIS automation tasks as a way to show how easy it is to automate routine things.

·      One was an application he built for a co-worker who was always being bothered by certain people who would stop to chat and never leave.  He used PYW to have it run with no console window. He made the script display a normal Browser logo, and actually fire up a website or program when clicked. But what it really did was, in the background, send emails to a couple of co-workers saying: “Help me, Obi-Wan Kenobi, you’re my only hope.”  That phrase tells them to call the co-worker, so she can tell the offender “Sorry, gotta take this call.”

·      Another was a script that would feed results of a webcam into an ERDAS PY library to convert to grayscale, then convert each pixel to an ASCII symbol; the darker the pixel, the fuller the symbol.  The resulting text-looking images were combined into a stream, so you ended up with a motion-picture in text symbols.

·      He also demonstrated a Python script that was GIS-oriented. He had the challenge during a recent upgrade of servers to change the SDE connections and MXD files used by all the users in his office, about 40, to see the new connections and data locations seamlessly. This he did by running a script after hours to edit their machines remotely, all executed in Python.


Thank you to our presenters and our venue. If you have any ideas for a presentation or any other matter, please contact a SLUG board member.  And thanks for your interest and support!