Thursday, February 28, 2013

Presenting property prices on maps

I came across an interesting post on Google Maps Mania blog pointing to a French real estate website with quite a novel approach to presenting property prices. While in Australia commentators focus only on median prices for capital cities, the French show the information at individual land parcel level (or close to it). Not to mention that they use “price per sqm” statistics - a much more useful measure for comparison and estimation of property values. The property prices map is a great example of presenting a huge volume of data in a very accessible and easy to digest format.  

The closest we came in Australia to such a map was a simple mapping app published by Fairfax on but unfortunately the map is no longer available. Creating a map similar to what accomplished would  be possible in Australia if you have access to price estimates as well as a full profile of each property – something only RP Data can afford in this country. In the past, I mapped property sales statistics for postcodes in Melbourne and Sydney but the information is not available on regular basis. So, in Australia, serious property hunters doing market research are limited to reading listings on real estate portals or buying property sales reports for individual suburbs.

Related posts:
Map of Melbourne house prices
Sydney house prices
WA housing affordability index
Aircraft noise maps
Mapping sun position anywhere

Tuesday, February 26, 2013

Great collaboration tool from TeamViewer

Imagine a situation when you are trying to ascertain why your software “doesn’t work as it should” on your client’s computer and your client is located on the other side of the world… What if you could login to that user computer and see the problem yourself?

Or imagine a situation that you are on the other side of the world and do not have access to a specialised software locally but that software happens to be installed on you home PC. What if you could login and use that software remotely?  

TeamViewer is a great tool that allows to “take over” a computer remotely, via the Internet. Host application requires installation but the other end, that runs on remote computer, is just a simple runtime executable. Users at both ends just need to synchronise connection by exchanging a line of digits representing a password. It is so simple and no programming skills or convoluted setup required…

Crime maps - complex stats visualisation

I am always on a lookout for good examples of maps presenting complex information in simple but very informative ways. The Washington Post map of Homicides in the District publicised on Google Maps Mania blog is a great example of a map summarising point data as coloured grid cells indicating counts of specific events in that location. Users can browse through multi-dimensional attribute data with simple drop-down selectors and the map is updated accordingly. It is a great way of demonstrating spatial distribution of events without undertaking complex spatial analysis, provided you input data is in a form of geocoded points that can be allocated to individual cells. 

An alternative way of presenting the information is to use “cluster marker” approach, as in this UK version of crime stats from the National Policing Improvement Agency.

The most basic approach is to provide summary information only for administrative polygons, as in this example from the Australian Capital Territory:

Related Posts:
UK crime statistics revisited

Mapping Crime in Canberra
MashupAustralia highlights

Friday, February 15, 2013

How not to build map portals

Anyone who tried to build a map based application or mapping portal will appreciate this light-hearted but very informative series of posts from Brian Timoney, titled Why Map Portals Don’t Work. There are 3 articles published so far, out of 5 planned on this topic. I share author’s views to the point but I will not even attempt to summarise the articles here - I could not possibly convey the message as well as Brian did. So, I will only limit the rest of my post to quoting a few gems:

…if you are building any public-facing interface you have exactly four requirements:

                   FAST  •  INTUITIVE  •  INFORMATIVE  •  FAST

Saying “no” to the premise of a single map portal serving both internal users and the general public is the prerequisite to building anything that will meet the four non-negotiable criteria stated above.

Map Portals Over-Focus on the Map, Under-focus on Text-Based Search and Discovery.

…build your simple single-topic maps to address the most common use cases…
single-topic maps get more than 3x the usage of [complex] portals.*

…slapping all of your layers on a single interface to placate the most demanding 3-5% of your audience sabotages the user experience of the vast majority.
* Based on a study undertaken by Brian Timoney of Local Government Maps for Denver

There are myriads of map portals and applications on the web that Brian’s comments directly apply to – some of my early applications as well. But I have learnt the lesson the hard way. If you are serious about saving time and cost, and creating great experience for your users, read the articles! Start your reading with this post that present results of a research “How the Public Actually Uses Local Government Web Maps: Metrics from Denver”. In itself it is quite telling piece of evidence of what works and what doesn’t work for map portals!

Direct links:
Why Map Portals Don’t Work – Part I
Paralysis of Choice: Why Map Portals Don’t Work, Part II
The Tyranny of “Requirements”: Why Map Portals Don’t Work, Part III

Thursday, February 14, 2013

Landsat 8 the newest bird in the sky

Big news this week was a successful launch of NASA’s latest Earth-observing satellite Landsat Data Continuity Mission (LDCM). The satellite will now undergo three months of testing in orbit after which all operational control will be transferred to USGS. From this moment the satellite will become known as Landsat 8. Data acquired by the satellite will continue to be collected by ground stations in South Dakota, operated by USGS, and in Alice Springs, operated by Geoscience Australia.

[Timeline showing lifespans of the Landsat satellites. Credit: NASA]

The Landsat mission began 40 years ago with the launch of Landsat 1 in 1972. The key objective was to study and monitor our planet’s land masses but with the advancement in science the range of potential uses of Landsat imagery expanded dramatically to cover many disparate disciplines, including study of climate, carbon cycle, ecosystems, water cycle, biogeochemistry, changes to Earth’s surface, effects of human activities on land surfaces, and much, much more.

Landsat 8 will orbit the Earth every 99 minutes and will be able to image Earth every 16 days. It carries two new sophisticated instruments, Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). These two sensors will provide seasonal coverage of the global landmass at a spatial resolution of 30 meters (visible, NIR, SWIR); 100 meters (thermal); and 15 meters (panchromatic). The OLI provides two new spectral bands, one tailored especially for detecting cirrus clouds and the other for coastal zone observations, and the TIRS will collect data for two more narrow spectral bands in the thermal region formerly covered by one wide spectral band on Landsats 4–7. The satellite is programmed to return 400 scenes per day (150 more than Landsat 7), increasing the probability of capturing cloud-free scenes.

All Landsat 8 data is free and will be available for download via Earth Explorer