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Hi,

 

I will calculate the average z-value of a ground surface based on a point cloud.

So at the moment I am using SurfaceDraper to drap the ground on the surface. After that I am using BoundsExtractor. But here I have only the possibility to get the min_zvalue. I will get the average z-value calculated on all z-values of the polygon.

image 

How can I do this? I saw thatt there is also an elevation extracotr. But this transformer only extract the first z-value of the first coordinate. I cannot calculate the average on al z-values. Can anyone give me some help or hints?

You can use a PointCloudStatisticsCalculator for that.

But for this I calculate the average z value for the hole pointcloud?

I will calculate average z-value for the drapedfeatures (ground surface of a building) after using surface drapper.

I have an idea. Maybe I can use AttributeCreator and add z-value by using fme feature functios (@ZValue()). After that I could calculate the average with the statistic calculator. But the feature function (@ZValue()) return only one z-value but I need all to calculate the average...

But for this I calculate the average z value for the hole pointcloud?

I will calculate average z-value for the drapedfeatures (ground surface of a building) after using surface drapper.

Just clip the pointcloud by the building footprint and use inside in PointCloudStatisticsCalculator 

Just clip the pointcloud by the building footprint and use inside in PointCloudStatisticsCalculator 

Ok than I would calculate the z-mean for all points inside the groundpolygon. Is it possible to calculate the z-mean limited on the ground vertices?

I have an idea. Maybe I can use AttributeCreator and add z-value by using fme feature functios (@ZValue()). After that I could calculate the average with the statistic calculator. But the feature function (@ZValue()) return only one z-value but I need all to calculate the average...

Hello @limo​, just a thought (not tested), it may be easier to convert the ground surface to a point cloud using the PointCloudCombiner, and then try using a PointCloudStatsCalculator to get average? Best, Kailin

Hello @limo​, just a thought (not tested), it may be easier to convert the ground surface to a point cloud using the PointCloudCombiner, and then try using a PointCloudStatsCalculator to get average? Best, Kailin

Yes this works for me. But I think I do not have to convert the ground surface to a point cloud. Because after clipping point cloud by ground polygon the result is already the ground as pointcloud. So this works for me fine. Thanks @caracadrian​  and @kailinatsafe​ 

I was just thinking only to calculate the average of the vertices of the ground polygon.

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