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pagliasofia Feb 14, 2014 01:37 PM
Good morning, I am working in Stata and ArcGis with LUZ and Corine Land Cover Data. I intersected 2009 LUZ boundaries with CLC data for 2000 and 2006, and then confronted them with land uses classes included in the 2009 LUZ dataset. I found discrepancies in the land cover classes, which then result in discrepancies in the measured total hectares. For instance, the Barcelona 2009 LUZ area amounts to 52.976 ha, while it amounts to 51.089 and 56.219 if intersected with 2000 and 2006 CLC, respectively. Similarly, for Milan, the difference is even higher, as 2009 LUZ area amount to 30.113 ha, while reaching 50.776 ha and 53.248 ha if intersected with 2000 and 2006 CLC, respectively. Differences can not be explained by assuming that land uses (generally) increased from 2000 to 2009. Could you help me please identify the mistake I do (although I re-checked the ArcGis and Stata procedures several times, also with the help of an expert) or the reason why it is so? Thank you very much for your kind help, sofia p.
Replies (6)
EEA Feb 17, 2014 12:42 PM
Hi Sofia P,
In principle, there’s no correlation between the two datasets. But could you provide us with the dataset location to be sure about the versions your are working on?
pagliasofia Feb 17, 2014 03:33 PM
Hello! Thanks a lot for your reply. I downloaded the LUZ data from http://www.eea.europa.eu/data-and-maps/data/urban-atlas (just for Barcelona and Milan), and I made a table of the total hectares per each land use. In ArcGis, I dissolved the LUZ boundaries for both cities, and intersected them (and later recalculated in hectares in ArcGis) with the CLC data I got from from http://www.eea.europa.eu/da[…]seamless-vector-database-4, for 2000, and from http://www.eea.europa.eu/[…]/clc-2006-vector-data-version-2, for 2006, using ONLY the 11 artificial land use classes.
Although I only used the 11 artificial land use classes for CLC data, and despite LUZ 2009 data include agricultural, semi-natural areas, forests, and water bodies, I was expecting similar values for the artificial surfaces.
Thank you very very much for your kind help, and thank you in advance for your time,
Have a nice day,
sofia p.
EEA Feb 26, 2014 03:59 PM
Urban Atlas (UA) and Corine Land Cover (CLC) are different datasets, obtained with different techniques and different input data: UA is derived from very high resolution imagery, while CLC is derived by high resolution imagery. Unfortunately, there’s no direct correlation between the two datasets, therefore some differences might arise.
pagliasofia Mar 04, 2014 05:58 PM
Thank you very much for the clarification.
pagliasofia Mar 04, 2014 06:02 PM
...So is it possible to say that, deriving from very high resolution imagery, UA data are more reliable?
EEA Mar 11, 2014 03:29 PM
UA input data are more detailed (qua very high resolution). Reliability of UA and CLC is difficult to assess in isolation from a given interest/use.