[GRASS-dev] [GRASS GIS] #3415: Mark raster NULL values as None in PyGRASS

[GRASS GIS]

#3415: Mark raster NULL values as None in PyGRASS
--------------------------+-------------------------
  Reporter:  marisn       |      Owner:  grass-dev@…
      Type:  defect       |     Status:  new
  Priority:  normal       |  Milestone:  7.4.0
 Component:  PyGRASS      |    Version:  unspecified
Resolution:               |   Keywords:
       CPU:  Unspecified  |   Platform:  Unspecified
--------------------------+-------------------------

Comment (by zarch):

 Replying to [ticket:3415 marisn]:
 > At the moment PyGRASS is providing raster NULL values as is (i.e. for
 CELL type they are marked as -2147483648). There is no function to check
 if value is NULL (in C it is done with Rast_is_c/f/d_null_value).
 >
 > The best would be to replace raster NULL values with None when raster is
 read and None with NULL representation when it is written back. Such
 approach would greatly simplify use of rasters in PyGRASS (i.e. "if
 myrast[row][col] is not None:")

 Well, but then for CELL raster instead to have an array of integer you
 will have an array of objects, I did not perform any benchmark but it
 seems not very intuitive as well.
 Perhaps we can define a `CELL_NULL` variable, and then you can write code
 as: `if myrast[row] != CELL_NULL:` or an equivalent function instead of
 `numpy.isnan` get `pygrass.raster.isnull`.
 What do you think?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/3415#comment:1>
GRASS GIS <https://grass.osgeo.org>