added more information to docs, /close #272

docs/_source/customise.rst

@@ -286,6 +286,35 @@ Custom Data Handler
   method is modified (see previous bullet).
 * (optionally) Overwrite the base class :py:`self.get_coordinates()` method to return coordinates as dictionary with
   keys *lon* and *lat*.
+* (recommended) It is highly recommended to stay with our naming convention of data axis for an better integration into
+  MLAir. In principle, the naming can be set from outside and changed to any naming, but this must be done consequently.
+  We recommend therefore to use the following convention:
+
+============== =========== =============================================================================================
+dimension name default     meaning
+============== =========== =============================================================================================
+time_dim       "datetime"  temporal axis, every new entry along this axis is assumed to be a new sample
+iter_dim       "Stations"  iter axis that is a collection of different data "sources", this could be a collection of
+                           stations or also a temporal split for a single year.
+window_dim     "window"    this axis is the "2nd" dimension of each samples. This could be 2D data if only a single
+                           timestamp is provided for each sample. In the default data handler, we use this dimension to
+                           provide lagged data in each sample.
+target_dim     "variables" the target dim indicates where to find the target vector. Furthermore, this also contains
+                           information on the "3rd" dimension of each sample. On input site, this can be used to provide
+                           different channels (e.g. color channels). On target site, this indicates the dimension along
+                           the target variable can be found. In the default data handler this dimension is used to flag
+                           different variables.
+filter_dim     "filter"    This is a custom dimension, which is used by some specific data handlers implemented by the
+                           authors. It could be described as the "4th" dimension. It is always possible to define a
+                           custom 4th dimension, but it could happen, that some parts of the code will not work very
+                           well with this additional dimension. But have a try and otherwise report a bug.
+============== =========== =============================================================================================
+
+
+.. note::
+
+    The following code snippets are not up to date currently. Please read the requirements above for in-depth
+    information what MLAir is expecting from a custom data handler!
 
 .. code-block:: python