Data Policy

The economic half life Geodata

At the ESRI UC Executive submit this weekend, Dirk Kempthorne the US Secretary of the Interior announced that the 35 year old archive of Landsat Imagery held by the USGS would be made available for free public access via the web. Of course how federal data is made available in the US has always been something we Europeans looked upon with some envy despite it’s sometimes poor quality, but it’s important to remember that Remotely Sensed Imagery has always been slightly different, and a less permissive licensing regime has existed around what was seen as a more commercial data set.

So this is great news, but it illustrates an interesting question ? What is the economic half life of geodata, over what period of time does the value of geodata decay ? The Landsat archive is in many ways different to “mapping” data in that the empirical value of data in the form of raw pixel values is still of considerable interest to the scientific community, but from the perspective of visual interpretation how much less valuable is a view of Las Vegas from the late 1980’s compared to one of today.

From a mass-market perspective there is a clear difference in usefulness, for providing a synoptic view of the world today to provide context for other types of information clearly geodata needs to be as current as possible, 10 year old imagery particularly for urban areas is much less useful. But financially how much less valuable.

For most types of commercial geodata this value decay curve is impossible to establish, because of the combination of software like licenses and copyright, so for example Ordnance Survey data in the UK has the same commercial value when it is one day old, one year old and 49 years old, but it then drops to zero as it drops out of copyright.

Alongside the broad argument around making public sector information more open, perhaps it would also be useful to think about the data that will always be commercial, but has a value which decays over time.

Written and submitted from the Google Office, London.

4 replies on “The economic half life Geodata”

This is an interesting article and provoked me to write. There’s long been contention about the cost/quality (and therefore value) of EU data – OS in particular – versus the US model. I can see the value of data is similar, although inverse, to the ‘price/performance’ graphs of IT in general – though in this case, ‘time/relevance’.

Though, I don’t see this as a linear graph – somewhere there’s a value point where it would be economically viable for the data vendor to still make money, whilst being of good use to the market. This would make more sense, surely, than the drop-off price point at 50 years.


The question you raise is interesting though has always been an obvious issue in regards to Remotely Sensed data. But, you’re also raising this question in reference to a mid-resolution source which is very typically only used in visualization environments as a texture-layer. Thus, it would be wiser, and based on my own experience with the data and application — is that the question be more specifically pointed toward higher resolution sources, and not Landsat, as Landsat will always retain a very high level of value due to its use as said.

I can take the USGS dataset and produce the best ever base-map of the entire world. The question is — do I really wish to do it again?

And an added criticism or whatnot to add suggestion: One must keep in mind that some of we Americans did not sign the document that the ASPRS sent out for member signature, so that this current Administration could plan for the upcoming Landsat Continuity Mission to become ‘commercialized’ through the USGS.

The irony being — that the acts that Clinton had signed into legislation were to boost an industry based on the premise that public domain datas would be beneficial to the industry to create ‘derived products’ from them, as well as affordable to access for scientific purposes and institutions. Unfortunately, this President doesn’t see it that way — and instead sees the dollar signs, that I would argue will only serve to limit the industry due to the massive costs associated.

I mean, we can sit here and argue tooth and nail about what legislation was passed and who was responsible for setting up a system wherein this data would have been freely available to society in a more immediate fashion — or we can pat the USGS on the back once again for not getting the job done the way they were required to from day one. It’s really up to anyone in the discussion to place everyone in check, in the hope that everyone begin doing the right things for once.

With ground level imagery I think the value will decline in the immediate term, but then increase as the historic aspect of the image becomes more relevant.

For example:

are images of Cleveland Street in central London. The Middlesex Hospital was still standing when the images were captured. As the site has now been demolished so these ‘viewsheds’ can no longer be created, thus making the images unique. Obviously the concept of value is always relative. With the move to digital imagery (and storage) there is also the bigger issue of whether we will be able to retrieve and view images captured in 2008 on a computer in 2028, but thats another (big) issue.


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