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For the purposes of spatial interpolation, I have created a grid using "Create Fishnet" in ArcMap10.2 (I use the "label points", which have a spacing of 0,00833333 degrees). For every point (label point) I want to have the mean elevation (aspect,curvature) in 800m. around the point. Any ideas how this could be performed?

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4 Answers 4

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  1. Convert the fishnet to point centroids.
  2. Buffer the points by 800m.
  3. Zonal Mean with the raster as elevation and the zone as the buffers.

I find your approach highly unusual but I am sure you have your reasons.

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  • the spacing is approximately 1km at the equator, therefore the point buffer will overlap and this could be an issue with zonal mean
    – radouxju
    Aug 26, 2016 at 13:38
  • @radoxju absolutely. That's what I was getting at in the last sentence of the answer. The question has some logical flaws but as I said I'm sure they have their reasons. Focal has issues as well.
    – If you do not know- just GIS
    Aug 26, 2016 at 21:30
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with spatial analyst, you can use Focal statistics to compute the mean for every pixel, then extract value to point in order to get this value at your point.

If you have only a few points, then you can create a buffer around the points, then you use "zonal statistics as a table" to extract the mean for each buffer. Or maybe directly use zonal statistics with your fishnet, but then this is not exactly 800 m "around".

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  • I have tried Focal statistics and the result is not what I want. I want the mean elevation for every fishnet point, not every raster pixel of the elevation. Concerning Zonal statistics I have tried that also, creating a buffer of 800m. around each point (equivalent to 0,009381358 decimal degrees at the latitude of my region) and then using the buffer zones to determine the shape of the area in which I want my mean to be calculated. The problem is that there are overlapping buffers, and thus, there are "overlapping zonal statistics".
    – Maria Karypidou
    Jan 30, 2015 at 21:40
  • You missed the critical step of extracting the "pixel" values to the fishnet points. A focal approach is really the most computational efficient way to accomplish your task.
    – Jeffrey Evans
    Jan 30, 2015 at 23:33
  • Thanks @JeffreyEvans for your comment. Focal stat is the best solution in this case. I've added the link to extract value to point for information
    – radouxju
    Jan 31, 2015 at 15:27
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Have you considered resampling the raster to the target 800 m resolution instead (possibly using a snap raster) using the Resample or Integrate tools and then converting the raster to points (possibly after applying the slope, curvature or aspect functions)? The result will be a regular grid.

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You can create theissen polygons around each of your points, and then compute the zonal statistics.This would make sure that only the elevations only get assigned to it's "closest" point from your fishnet. This of course, assumes your 800m area of draw for the mean elevation isn't a hard parameter and all elevation assigned to a point only gets assigned to that point.

If the 800m parameter is a requirement, the previous poster's suggestion of buffer the point and extract zonal statistics is correct. Even if there are overlapping buffers, set a zone field (unique zone id) and generate the statistics that way.

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