10/4/2011 Sinkholes in Florida

I am in the process of purchasing a house in Spring Hill, Florida (Hernando County). In today’s discussion with the insurance company, they said “Well, of course, you need insurance for sinkholes.”

WHAT!!!!

Of course I have heard of sinkholes, but I thought they were very far-and-few-between – the stuff of headlines:

GERMANY - A giant sinkhole under a residential street opened up on Monday in central Germany. ...
GERMAN SINKHOLE link

GYPSUM (AP) - Sinkholes have been popping up near long-abandoned mines along a busy Lake Erie highway, and the state plans to fill in some of the tunnels before the holes reach the road. ...
Sinkholes near Gypsum prompt monitoring link

but, living here in relatively-geologically-stable New England, I think that “sinkhole insurance” is about as necessary as “elephant-through-your-living-room insurance”. But maybe Florida is different – let’s use our GIS resources and knowledge to investigate!

Because the tool is there, and so easy to use, let’s “Google Map” the house: 34606 Parlow Avenue, Spring Hill, FL:

And let’s zoom out to see the major highways on the east (589) and the west (19):


Also because it is easy to use, let’s Google “database of sinkholes”. Maybe Google knows I’m a GIS guy, or maybe I’m just lucky, but the first hit looks promising:

FGS, Sinkholes in Florida
webpage link

It is the Sinkholes page for the Florida Department of Environmental Protection – certainly a trustworthy source! Scroll down to the bottom, and in the Sinkhole Resources section, download and open Florida’s Sinkholes (Poster No. 11) Contact FGS to purchase this 24” by 36” poster


Depending on the size of your computer monitor, this is a pretty scary poster! Especially when you realize that Spring Hill is on the west coast just north of Tampa Bay! Let’s try to find some Good News.

First, though, what county is Spring Hill, Fl in? Wikipedia says that “Spring Hill is a census-designated place (CDP) in Hernando County, Florida”. We will see below that is a good assumption.

Back on the Sinkholes page, scroll down to the bottom, and in the Sinkhole Resources section, download and open Sinkhole type, Development and Distribution in Florida Map (Map Series 110). This is a beautiful thematic map of Florida, produced by the USGS in 1985, with soils divided into four areas related to sinkhole type:

Zoom in on Hernando County:


And we see that Hernando County has three-of-the-four areas:
Yellow is Area I – “Sinkholes are few, …”
Green is Area II – “… Sinkholes are few, …”
Blue is Area III – “… Sinkholes are most numerous, …”

So where is our property in Hernando County, in relation to these yellow/green/blue areas???

Open MapInfo, and open a County file, and open a Streets file, and zoom-in on Hernando County:


I have put a Gold Star in the area of the house. Comparing it with the USGS map, it looks like the house is in the green area under the “H” in “Hernando”. That’s Good News!

Maybe I should leave well enough alone/let sleeping dogs lie, but let’s see if there is a database of actual sinkhole locations. Back on the Sinkholes page, the left column has a Data & Maps link. Click it to get to the Data and Maps window:

By now, I realize that “sinkholes” are also referred to as “subsidence incidents”, which sounds much nicer. Click on the link for Subsidence Incident Reports to get to the Subsidence Incident Reports page:

Scroll down, and download the ESRI ArcGIS compatible shapefile. Unzip the file and bring it up in the MapInfo screen you worked on before:

Um, I don’t feel so happy anymore – there are sinkholes (“subsidence incidents”) all around the new house! Maybe the USGS should update its map/geologic database. Let’s make a copy of the sinkhole file (only County = “HERNANDO”, and only the oyear column [original reported year]), bring it up, and color the dots by oyear. This will allow us to see if the sinkholes happened back in the Sixties or Seventies, or if they are more recent:

Well, most happened in the 1990’s. Zoom-in on the house:

Using a radius tool, we see that the closest reported sinkhole is purple 0.4 miles to the west, and the closest red one is 0.6 miles to the northeast. I guess it is time to call the insurance company and get some “sinkhole insurance”.

10/1/2011 Red Sox September Swoon

(As a tip-of-the-hat to my Florida relatives and friends, this column could be called The Rays Astounding Ascent)

On the morning of September 4, the Boston Red Sox, at 84-54, although ½ game behind the New York Yankees, were nine games ahead of the Tampa Bay Rays (75-63) in the Wild Card race. Over the following 24 days
- the Red Sox went 6-18 (winding up at 90-72),
- the Rays went 16-8 (winding up at 91-71),
- and the Rays are in the Playoffs.

I pulled the 2011 American League East daily results into a Google Docs spreadsheet, and added their Motion Charts gadget (see my 1/2/2011 blog). Because the beginning-of-April results were so wacky from a percentage standpoint (the Baltimore Orioles won their first four games, and the Boston Red Sox and the Tampa Bay Rays both lost their first six games), I decided to look at the results beginning May 1.

Information can come in many formats, so I decided to see “the Swoon” in motion. Right-click this link and "Open in a new window"
http://www.dixonspatialconsulting.com/HTMLredsox.htm [NOTE: users without the capability to right-click should open a new window, go to this blog, and just click the link in that new window]
Please follow instructions to modify the Chart that appears

Change the x-axis from percentage to Time

In the upper-right, change Same color to Unique colors, and check the boxes for Boston Red Sox, New York Yankees, and Tampa Bay Rays. Then click the Play button in the lower-left, and watch the season unfold:

If you change the x-axis to Order: Alphabetical, and uncheck Trails, you get a good vertical display of the season:

But I feel the most effective visualization (well, maybe not most effective, but most tragic) comes when you click on the Bars tab
, then click Play. For almost all of the season, the two left columns are swapped between the Yankees and the Red Sox – it is only on the Last Day that the Rays replace the Red Sox in second place:

Too bad for Boston, but congratulations to Tampa Bay!