Tuesday 30 June 2015

A little more on the "omission error" for the woodland areas

To have a bit more of a look at the areas that are woodland in OS VectorMap and not classed as woodland in the classification, I here show where these areas are on the satellite images, and the classes that these areas are in fact assigned.

June 2006


Showing the areas indicated as woodland in OS VectorMap but not by the classification outlined in black, overlaid on the Landsat 7 image from 9th June 2006 (bands 5,4,3). large version

Showing the actual classifications the "omission error" areas were assigned. large version

March 2007


Showing the areas indicated as woodland in OS VectorMap but not by the classification outlined in black, overlaid on the Landsat 7 image from 24th March 2007 (bands 5,4,3). large version

Showing the actual classifications the "omission error" areas were assigned. larger version

September 2013

Showing the areas indicated as woodland in OS VectorMap but not by the classification outlined in black, overlaid on the Landsat 8 image from 24th September 2013 (bands 6,5,4). Some areas that display in pink here appear to be recently felled forest areas that have a weak reflectance in NIR (shown in green), but strong in SWIR1 (shown in red) with some reflectance in red (shown in the blue channel here). large version

Showing the actual classifications the "omission error" areas were assigned, and the 'cloud' areas. Some shaded areas are spuriously being classified as water. large version

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