@davidhassell commented on this pull request.
> + +Adjacent interpolation subareas that are in different continuous areas never share tie point coordinates, as consequence of the grid discontinuity between them. This results in a different number of tie point coordinates in the two cases shown in <<interpolation_subarea_generation>>. + + + +For each interpolated dimension, the number of interpolation subareas is equal to the number of tie points minus the number of continuous areas. + +[[interpolation_subarea_generation, figure 1]] +[.text-center] +.Process for generating the interpolation subareas for a grid without discontinuities and for a grid with discontinuities. +image::images/ci_interpolation_zone_generation_process.svg[,100%,pdfwidth=50vw,align="center"] + +[[compression-by-coordinate-sampling-tie-points-attribute, Section 8.3.2, "Coordinate Interpolation Attribute"]] +==== Coordinate Interpolation Attribute + +To indicate that coordinate interpolation is required, a **`coordinate_interpolation`** attribute must be defined for a data variable. This is a string attribute that both identifies the tie point coordinate variables, and maps non-overlapping subsets of them to their corresponding interpolation variables. It is a blank-separated list of words of the form "__tie_point_variable: [tie_point_variable: ...] interpolation_variable [tie_point_variable: [tie_point_variable: ...] interpolation_variable ...]__". For example, to specify that the tie point coordinate variables `lat` and `lon` are to be interpolated according to the interpolation variable `bi_linear` could be indicated with `lat: lon: bi_linear`. ```suggestion To indicate that coordinate interpolation is required, a **`coordinate_interpolation`** attribute must be defined for a data variable. This is a string attribute that both identifies the tie point coordinate variables, and maps non-overlapping subsets of them to their corresponding interpolation variables. It is a blank-separated list of words of the form "__tie_point_coordinate_variable: [tie_point_coordinate_variable: ...] interpolation_variable [tie_point_coordinate_variable: [tie_point_coordinate_variable: ...] interpolation_variable ...]__". For example, to specify that the tie point coordinate variables `lat` and `lon` are to be interpolated according to the interpolation variable `bi_linear` could be indicated with `lat: lon: bi_linear`. ``` -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/pull/326*pullrequestreview-699771723__;Iw!!G2kpM7uM-TzIFchu!k9hIBnH8_eZ7n_aQ_H3H77YvVonwfyaWvXQ2sJUrwBB6kyVlxWqYyZAb3DiMV9uO8B5fbcjMhRg$ This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
