This heat map created is a graphical two-dimensional representation of the data census figures from 2011 with the random distribution of counties and their boundaries across Ireland, their values are represented by colours. This fairly simple heat map provides an immediate visual summary of information. I have used colour to communicate relationships between the two data values that would be much harder to understand if presented numerically. Ok in the, Irish population example, I got two tables: one contains county-by-county population figures, the other one contains geographic information of each state and its borders and I uploaded them to fusion tables, were I merged the two tables. I was able to then visualize the new merged table on a map and subsequently applied a style to the map. The fusion table was able to pull county names, population figures and border information and outline the facts onto a base map.
Counties are coloured and categorized according to their population density. The graduated colour scheme allows for a quick and easy analysis of this data. It is evident from the map that the yellow coloured counties (e.g. Dublin, Galway and Cork) are the most densely populated areas with more than 250,000 people living in these counties. It is also apparent that the orange coloured counties (e.g. Leitrim) are the least densely populated with between (15,000 and 55,000) living in these areas. It is also therefore easy to surmise that the population density of the light green shows a big concentration of between (55,000 and 87,000) right up through the midlands and into Sligo.
By using the filter option on heat maps you can isolate different values take total population for instance this can be selected and used to see these values mapped in relation to Ireland. Secondly heat maps can be sorted in ascending or descending order. This is useful when trying to decipher quickly which areas have the lowest and highest values (e.g. figure out which county has the most females), or it is excellent when trying to quickly search for areas with specific values (you want the results on male population in Ireland so that counties with between 65,000 and 150,000 males are only displayed on the map, as shown below. This map could also provide an interactive and visualization aid for the distribution of the elderly population across Ireland.
From a conceptual point of view the preparation of heat maps can now cover a wide range of variables, not just population figures and distribution of counties. Areas like religion, nationality, education, social class, industry of employment, occupation, housing, cars per households and health and disability all fall under this theme, you could even have a scenario were you have a number of different variables to show the percentage of households with central heating powered by peat and map them accordingly, you might even be able to elaborate on the type of fuel used, the type of sewage system, the tenure(is it owner occupied or rented) or the actual type of housing unit(detached, one bed apt etc.). The possibilities are endless and one thing is for sure it without doubt shows very clear patterns throughout the country for whatever geo-spatial mapping you require.