Data — Land cover database CIGAL 2011/2012 v2 (BdOCS20112012-CIGAL v2) — Alsace

The land cover spatial database CIGAL 20112012 v2 originated from the update of the CIGAL 2008 v2 soil octcuaption database by photointerpretation of the Alsace region at nomenclature level 3 and 4. The thematic and geometric reference images are the CIGAL orthophotographs of resolution 20 cm of 2011 for the Bas-Rhin and 2012 for the Haut-Rhin. The creation of the BdOCS20112012-CIGAL v2 s' is based on the existing limits of BdOCS2008-CIGAL v2. Only the contours and/or codes of the land use change zones between the 2 dates have been modified. This data set has been produced to allow optimum exploitation on the scale 1/10 000. The study area represents an area of 8 330 km² and covers Alsace. The information layers have also been generalised and are available for exploitation at 1/50 000th (level 2 of the nomenclature) and 1/250 000 (level 1 of the nomenclature). __Origine__ The land cover spatial database CIGAL 2011/2012 v2 was produced by Computer Assisted Photo-Interpretation (PIAO), i.e. directly on the screen by scanning objects of land cover on the various aerial photographs at 20 cm in the study area, according to the BdOCS nomenclature established by the CIGAL partnership. The PIAO builds on the many exogenous data that are pre-existing and made available. The so-called CORINE Land Cover nomenclature comprises 4 hierarchical levels, comprising 4 themes at the general level and 55 typology posts of land cover at the most detailed level. The digitisation and interpretation scale is 1/8 500 for a recommended operation at a scale less than or equal to 1/10 000. The minimum interpretation width of linear objects is 12 metres. To ensure good reliability of the BdOCS20112012-CIGAL v2, two quality controls have been established. One in-house (CQI) performed by SIRS, the database producer, and the other externally (EQC). In addition, confusion matrices by department were carried out. The reliability rate is qualified in the “Reliability” attribute of the GIS data. The overall reliability rate is 85 % throughout the country. The information layers have also been generalised and are available for exploitation at 1/50 000th (level 2 of the nomenclature — 11 posts) and at 1/250 000th (level 1 of the nomenclature — 4 posts). __ Partner Organisations__ CIGAL, SIRS __Links annexes__ * [methodological report](https://www.geograndest.fr/metadata/geograndest/FR-236700019-BdOCS20112012-CIGAL-V2/CIGAL_BdOCSv2_RapportMethodologique_v130614.pdf) * [user guide](https://www.geograndest.fr/metadata/geograndest/FR-236700019-BdOCS20112012-CIGAL-V2/CIGAL_BdOCSv2_GuideUtilisateur_v131122.pdf) * [license](https://www.geograndest.fr/metadata/geograndest/FR-236700019-BdOCS20112012-CIGAL-V2/Etalab_Licence-Ouverte-Open-Licence.pdf) [See this sheet on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/f7f668a51a4316d3cc01010518e9b86c6ee123a2)