How to determine "write_slf_header" header variable "seek_head"

[KayShelton]

I am trying to write data to a .slf file using the "write_slf_variable" function. Before doing this, I need to create the file with "write_slf_header", providing the header information describing the contents of the file. One list value needed in the header is the "seek_head" effectively giving the length of the header. The documentation on this says this can be inferred from "read_slf_header" but as I am writing a new header with new information, I don't now how to specify the new seek_head. Please can you provide information on how I should determine the value for this?

[tpilz]

For writing you actually don't need the seek_head information. It should work just leaving it out. I admit that the function's doc is a bit unspecific here.

However, note that the write_slf_* functions are low-level functions. It is usually much more convenient to use the geo() or write_results() function which are basically wrappers around the write_slf_* functions.

[KayShelton]

Thanks @tpilz , good to know. I am trying to meteorological data (winds and pressure from ERA5) to the node points on a mesh for use by a colleague to run Telemac - I won't be running the model myself (and have no experience running it). They want all the met data in a single slf file as an input, so I figured this was the best way to go about it. Would you suggest otherwise?

[tpilz]

This depends on how these meteorological data have to be provided -- I have no experience here. When they have to be provided along with the mesh in the geometry file you can use function cas() as shown in this vignette for CN and DEM elevation when using the rainfall-runoff module. If it works differently for the module you (or your colleague) are using you are maybe right to go with the write_self_* functions.

[KayShelton]

Much appreciated @tpilz. I managed to get it all sorted with the write_self_* functions, and they seem to read back in correctly with the read_slf_* functions. Thanks for your confirmation on the requirements.