Difference between revisions of "Import of kNN"
(New page: '''The ''k''NN-Sweden data''' consist of pixelwise estimates of forest states.) |
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| − | '''The ''k''NN-Sweden data''' consist of pixelwise estimates of forest states. | + | '''The ''k''NN-Sweden data''' consist of pixelwise estimates of forest states. A complete coverage is possible by using remotely sensed information, usually satellite image data. Sensors onboard, e.g., a SPOT satellite obtain spectral signatures in different wavelength bands (usually IR, R, G, and B) in each pixel, with a ground resolution approx. corresponding to 25 by 25 meters. Geo-referenced, previously inventoried NFI-plots will serve as reference data. In the feature space, defined by the satellite image, the ''k'' Nearest Neighbours (usually with ''k'' = 10) are found among the reference plots. Estimations of volume, age, tree species composition, etc. are then derived as weighted mean values (e.g. weighted inversely proportional to the distance in the feature space). |
Revision as of 16:45, 8 September 2009
The kNN-Sweden data consist of pixelwise estimates of forest states. A complete coverage is possible by using remotely sensed information, usually satellite image data. Sensors onboard, e.g., a SPOT satellite obtain spectral signatures in different wavelength bands (usually IR, R, G, and B) in each pixel, with a ground resolution approx. corresponding to 25 by 25 meters. Geo-referenced, previously inventoried NFI-plots will serve as reference data. In the feature space, defined by the satellite image, the k Nearest Neighbours (usually with k = 10) are found among the reference plots. Estimations of volume, age, tree species composition, etc. are then derived as weighted mean values (e.g. weighted inversely proportional to the distance in the feature space).