Monday, April 16, 2012

Map of Melbourne house prices

Every time I come across a data table with information that can be referenced to a location I ask myself a question why the publisher did not consider adding a map? Data presented in spatial format is so much more informative than just plain tables. Yet, still not much “data journalism” is happening in Australia. Agree that more elaborate presentations are time consuming and expensive to create but these days adding a map to an article can be done almost in an instance.

For example, a few days ago I came across a post on propertyobserver.com.au which referenced information from the Real Estate Institute of Victoria on median house prices, and changes over time, for Melbourne suburbs. Since each suburb has well defined spatial extents, the information can be easily presented on a map. Numeric values relating to individual suburbs, such as median price or year-on-year change in price, can be represented with different colours on the map, giving the reader visual clues about how specific suburb compares to other suburbs.

I have created two separate maps with the data. The first shows median house prices by suburb and the second maps changes in prices over the year. There are many different ways how the data could be divided and categorised to present it on the map in a meaningful way. I opted for a very simple approach - median prices are divided into quartiles and changes in prices are split into 5% intervals. In particular, on the first map dark red indicates 25% of the most expensive suburbs (i.e. with median prices over $730,000) and the cream colour refers to 25% of the cheapest suburbs, with median prices under $420,000. The median value of median house prices is $577,000 (i.e. 50% of suburbs on the list have a lower median price than that).



The second map uses contrasting colours to present two extremes: suburbs where prices fell in the last 12 months (in various shades of blue) and suburbs where prices increased (warm colours from pale green, through yellow to dark red). The darker the colour the higher the decline/ increase. Although blue colours dominate on the map, implying more suburbs with declining median house prices than rising, those suburbs are distributed throughout the city without any obvious pattern.



Presenting information on Google Maps can add some interactivity to otherwise static articles and will help to engage the readers. Data journalism with presentation of information on interactive maps and charts has been proved very successful in the US, UK and Canada. Australia is yet to follow in any major way. I will be happy to assist!

Related posts:
Sydney house prices

Maps and property investment
WA housing affordability index
Aircraft noise maps
Mapping sun position anywhere
Gauging Australian property market

6 comments:

Anonymous said...

I agree about maps being so much more informative than plan data tables. This is one of the reasons why Council Map Server was created.

Arek said...

Welcome to All Things Spatial and thanks for your comment. Mapping applications still have only low exposure to users. Ongoing education about the benefits is so important...

Anonymous said...

I'm not sure if this is just a problem with my browser, but the maps aren't loading.

It's just a small image of the earth spinning around forever.

Arek said...

Unfortunately, since Google disabled maps v2, this application will not longer work. I am releasing an updated versions in the future but it will have different functionality. Please visit this blog in a few weeks...

Aamy said...

Hello Arek, have you updated your application. Btw, your work is awesome!

Arek said...

Not yet but your comment made me even more determined to finish it as soon as possible. Stay tuned!