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I need to identify the roofs of buildings using a satellite image, something like what is available in OSM something like that (something like the image).

Is there anyway to do this in Qgis, R, Arcmap?

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    Vote to close as too broad - the answer is somewhere between Msc and PhD thesis in size. – Mikkel Lydholm Rasmussen May 29 '18 at 16:11
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    I'm not sure where you have seen MsC or PhD doing this. We have done supervised classifications like this (with fairly high degree of accuracy) in an introductory Remote Sensing course. Where is the line to get the PhD? In all seriousness though, this is something that can be accomplished by any person with RS background in a day (given the imagery). – Ruslan May 29 '18 at 19:34
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Especially through OSM, these types of features are typically digitized. Otherwise, it would likely take developing an intensive script/algorithm to process imagery tiles, orthophotos, and obliques.

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Try using Image Classification in the Spatial Analyst extension (in ArcMap).

Open the Image Classification toolbar, you will create training samples of roofs. In the Training Sample Manager, the training samples will list and can be renamed to what you are identifying (ie. rooftops). Sample a few different colored rooftops, and then merge the training samples into one in the manager window.

Use the Maximum Likelihood Classification tool or Interactive Surpervised Classification tool to classify the image. Look over the results to see if you need to reclassify the image samples to clean up the result (if something else in the imagery appears to be the same color as the rooftops, the tool can misclassify).

This tool can be helpful but is only as good as it's inputs and may take a few tries. Hope this helps.

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