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.