The Trend Surface operation is a point interpolation which requires a point map as input and returns a raster map as output. One polynomial surface is calculated by a least squares fit so that the global surface approaches all point values in the map. The calculated surface values are assigned to the output pixels.
The trend surfaces in this operation range from a simple plane to complex polynomial surfaces. You can usually select a first or second order function to calculate the surface, as these are the least sensitive to produce extreme values. For more information on the available functions which calculate surfaces, see Trend surface : algorithm.
Input map requirements:
The input point map should be a value map. Furthermore, when a point map uses a class or ID domain and the map is linked to an attribute table, you can also use such a point map and select a column with a value domain from the map's attribute table.
Domain and georeference of output map:
The output raster map uses the same value domain as the input point map or the attribute column. The value range and precision can be adjusted for the output map. The georeference for the output map has to be selected or created; you can usually select an existing georeference corners.
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