I have the aspect (raster file) for the roof of buildings at the city scale. Now I want to calculate the area of each aspect group per building. I tied zonal statistics, zonal geometry and etc . Also reclassified the aspect layer and tried to add the Building ID. But I didn't get the desired result. Is there a way to do that? Kindly see the attached
to do it on a per building basis you need the individual 'zones' which can be accomplished using.
Region Group—Help | ArcGIS Desktop
the resultant would be your zone file, then a zonal count would give you the number of cells (times cell area) per aspect by building
You should also read this blog post...
Thanks Dan! I performed the region group, then displayed with the link value (shows exact values as for aspect.tif). Also did zonal statistic with the feature zone as the regiongroup.shp + the zone filed as count+ value raster (uploaded aspect.tif). But still didn't get the desired result . I think I am missing something , can you please illustrate the second step in more detail.
need to see what your desired result is in light of what you have.. it may need an interpretation suggestion or modification
After visualizing the product of Region Group , it seems that it is not giving the zone needed (top classification by value bottom classification by Link).
something doesn't look right. You need to regiongroup your original zones. Then you use that for the zonal statistics on your aspect. You don't regiongroup the aspect
Thank you for your time! I do agree with you, but I did regiongroup for the building footprint first but it didn't give what I needed. That is why in the second attempt I did the regiongroup for Aspect. It is worth to mention that both layers follow the same grouping pattern when I reclassify the value, with the exception of the No. of elements in the attribute table -which are different- .
regiongroup produces the zones for zonal statistics operations.
now you need to do the zonal statistics
I notice that you have an incredibly large number of zones, suggesting that your input raster wasn't cleaned up and you probably have a whole load of zones that consist of 1 or 2 cells. You could use nibble to fill those in with adjoining values, but I suggest that it might be worthwhile getting a clean vector file of the building footprints and start the zonal statistics from that