switch order of examples for clarity

base_classes/NXdata.nxdl.xml

@@ -142,7 +142,28 @@
 
  Note that `@x_indices` and `@y_indices` attributes can be omitted in this case. However it is strongly encouraged to provide them.
 
- `2. Multi-dimensional axes`
+ `2. Data dimensions spanned by more than one axis`
+
+ A common case is the need to specify alternative axes for the same dimension
+
+ .. code-block::
+
+ data:NXdata
+ @signal = "data"
+ @axes = ["eta", "q"]
+ data: float[10,20]
+ @eta_indices = [0]
+ @tth_indices = [1]
+ @q_indices = [1]
+ eta: float[10] --> coordinates along the first dimension
+ tth: float[20] --> coordinates along the second dimension (alternative)
+ q: float[20] --> coordinates along the second dimension (default)
+
+ Note that to recognize `tth` as an axis, `@tth_indices` must be present. Readers that do
+ not use :ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>` attributes will
+ have no way to understand that `tth` is an axis and simple ignore it.
+
+ `3. Multi-dimensional axes`
 
  When coordinates do not form a regular grid, multi-dimensional :ref:`AXISNAME </NXdata/AXISNAME-field>` fields
  can be used. Just remember that the shape of an :ref:`AXISNAME </NXdata/AXISNAME-field>` field must be equal to the shape
@@ -171,7 +192,7 @@
  This would be invalid since the shape `[10,20]` of `x` is not equal to the shape `[10]` of the spanned data dimensions.
 
  Omitting indices for multi-dimensional axes can only be done by repeating the :ref:`AXISNAME </NXdata/AXISNAME-field>`
- name in all positions of the :ref:`axes </NXdata@axes-attribute>` attribute which they span.
+ name in all positions of the :ref:`axes </NXdata@axes-attribute>` attribute which they span. For example
 
  .. code-block::
 
@@ -184,8 +205,6 @@
  Note that since ``NXdata`` does not describe how the data is to be plotted or even the dimensionality of the plot,
  a reader would probably treat this particular example as a 1D signal and plot it as such.
 
- `3. Dimensions spanned by more than one axis`
-
  In the case of multi-dimensional axes, single-dimensional axes are often introduced as default axes
  to support readers that does not use the :ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>` attributes
  or cannot handle multi-dimensional axes.
@@ -212,25 +231,6 @@
 
  Technically `@x_set_indices` and `@y_set_indices` can be omitted. However it is strongly encouraged to provide them.
 
- Another common case is the need to specify alternative axes for the same dimension
-
- .. code-block::
-
- data:NXdata
- @signal = "data"
- @axes = ["eta", "q"]
- data: float[10,20]
- @eta_indices = [0]
- @tth_indices = [1]
- @q_indices = [1]
- eta: float[10] --> coordinates along the first dimension
- tth: float[20] --> coordinates along the second dimension (alternative)
- q: float[20] --> coordinates along the second dimension (default)
-
- Note that to recognize `tth` as an axis, `@tth_indices` must be present. Readers that do
- not use :ref:`AXISNAME_indices </NXdata@AXISNAME_indices-attribute>` attributes will
- have no way to understand that `tth` is an axis and simple ignore it.
-
  `4. Axes without defaults`
 
  Expanding on the 2D scatter example, a stack of 2D scatter data where the stack dimension