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pagliasofia Jul 24, 2013 09:38 AM
I am checking the CLC data 2000-2006 in excel at NUTS3levels.
Regarding transport areas (a sum of roads, airports and ports), there are some NUTS3 levels that do not have any transport area whatsoever, (so the sum is equal to 0; e.g. AT124, AT125, BG425, DE218), while there are some (e.g. DE242, DE249, PT168, ITD54) that show an increase between 2000 to 2006 from 0 to some hectares of transport areas.
How is it possible? If the transport areas in 2000 are 0, does it mean that the transport areas (roads, airports or ports) at that time were not captured because they are below the 25 ha threshold? Or shall I treat these data as missing?

Thank you very much if you can help me with this.
sofia p.
Replies (3)
EEA Jul 26, 2013 10:37 AM
Dear pagliasofia,
Good point. The reason for no transport area may be that they are either under 25ha coverage or under 100m width (Minimum Mapping Unit) threshold.
The CLC is generally underestimating transport infrastructure due to those Minimum Mapping Units. There are some regional differences as some countries might have mapped transport areas that were close or even under the Minimum Mapping Unit limit whilst others have not ...

Best regards!
pagliasofia Jul 26, 2013 12:15 PM
Thank you very much for your reply. So what do you think could be the most appropriate way to treat the CLC data statistically? As 0s or missing? My choice would be to treat them as 0s but I am checking several sources to take a final decision. Thanks again.
EEA Jul 29, 2013 09:15 AM
Dear pagliasofia,
I sent your question to one of our experts. Please find his answer below:

Definitelly as 0s to be consistent - with referring to the data source CLC (disclaiming all its Minimum Mapping Units – 25 ha and 100 m).
There are other sources for transport infrastructure coverage – countries statistics or GIS layers as OpenStreetMap, EurogeographicMap or TeleAtlas (commercial).

Hope that helps.