Add -inf inf and nan (#8665)

docs/user_manual/processing_algs/qgis/rasteranalysis.rst

@@ -2869,16 +2869,18 @@ Basic parameters
      - ``MIN_FIELD``
      - [tablefield: numeric]
      - Field with the minimum value of the range for the class.
+       Use ``-inf`` to capture the lowest possible value.
    * - **Maximum class value field**
      - ``MAX_FIELD``
      - [tablefield: numeric]
      - Field with the maximum value of the range for the class.
+       Use ``inf`` to capture the highest possible value.
    * - **Output value field**
      - ``VALUE_FIELD``
      - [tablefield: numeric]
      - Field with the value that will be assigned to the pixels that
        fall in the class (between the corresponding min and max
-       values).
+       values). Use ``nan`` to set the value of the range to NoData. 
    * - **Reclassified raster**
      - ``OUTPUT``
      - [raster]
@@ -3004,6 +3006,8 @@ Basic parameters
      - A 3-columns table to fill with the values to set the boundaries
        of each class (``Minimum`` and ``Maximum``) and the new
        ``Value`` to assign to the band values that fall in the class.
+       The value ``-inf`` can be used as minimum, ``inf`` as maximum,
+       and ``nan`` can be used to set the output value to NoData.
    * - **Reclassified raster**
      - ``OUTPUT``
      - [raster]