Saturday, March 31, 2012

Irish landed estates database 'heatmap'

I am involved with a project to catalog Irish landed estates in conjunction with the Moore Institute at the National University of Ireland, Galway. Right now the database covers the provinces of Muster and Connaught.

The web site includes an interactive map which visitors can use to browse for houses and estates of interest. I thought it might be interesting to make a 'heat map' of the areas which people found the most interesting.

Every time someone zooms into an area on the map, the database is queried for records matching that rectangular area. The web server logs record all these queries (anonymously of course).

The image on the right was generated by summing about half a million of these database queries. I had intended to super-impose the heat map on a Google map, but unfortunately I don't have the time to complete that right now. However one can see the distinct outline of the west and south of Ireland coast line with hot spots around the cities of Galway and Limerick. (Why there is no hot-spot around Cork city? I have no idea!)

Wednesday, March 14, 2012

The weight ratio of dry pasta to cooked pasta

It's not often you ask Google a simple question and you can't get a straight answer. My question was this: "what is the weight ratio of dry pasta to cooked pasta?"

There is plenty of discussion on this matter, with units such as ounces, cups, Fahrenheit, buschels and microfortnights bandied around. But not one answer that had the simple dimensionless ratio I was looking for.

So it's off to the lab (... well kitchen ...) to do an experiment:
  • 100g fusilli (Lid's finest)
  • 500ml water
  • Bring to boil and boil for 10 minutes
  • Strain pasta
  • Weigh pasta
So what is this magic ratio? Well, this is not an exact science. Obviously al dente pasta is going to be lighter than over cooked. And it's probable that the topology of the pasta will have some influence on it's ability to retain water. Pasta topologies with lots of surface area and enclosed spaces (eg pasta shells) are going to have more water clinging to the surface. These are experiments for another day.

Anyhow, as for fusilli, the cooked weight of 100g of dry pasta after 10 minutes boiling was 208g.  So the weight ratio of dry pasta to cooked pasta is

1 :  2.1

Thursday, March 8, 2012

Visualizing diurnal temperature variation

I've been logging temperature from a ZigBee temperature sensor (located in my shed in the back garden) since about November last year. I thought it would be interesting to see the diurnal (daily) temperature variation over time. On the x-axis are days (from about 10 November 2011 to 7 March 2012) and on the y axis is time-of-day, with midnight being at the very top and bottom. Temperatures vary from about -3C (deep blue) to +15C (red). Periods where there is no data are gray. Sorry no legend or axis markings.

The chart was constructed by averaging temperatures into 15 minute bins (with about 5 samples per bin) and plotting each bin as a rectangle in SVG. I then used rsvg to convert to a PNG image.

For comparison here is a chart for the same time period of my home office temperature. The color scale is different, deep blue being 12C and red 22C.