Matthias used the class '_active' to classify the highest object in all available 'urban' objects. In a loop, he fused this '_active' object with the neighbor objects using the 'image object fusion' algorithm.

The '_active' class will be used by the 'find domain extrema' algorithm.

Hi Nikhil,

Yes! Christian is correct.

I use this temporary class in the "find domain extrema" alg.. In the provided rule set it looks into the class "urban" and assigns the class "_active" to the object with the highest value in the "DSM". Afterwards this "_active" object is used in the image object fusion alg. as a "seed-object" to grow from. This allows me to work my way through all "urban" objects from top (highest) to bottom (lowest in DSM). Afterwards I simply reclassify the "_active" class into "building" and then after the loop is finished it starts again, with assigning the class "_active" to the highest "urban" object, followed by the image object fusion and so on.

Cheers,
Matthias