[GRASS-dev] Temporal framework: Proper way to register new maps from a python module?

[Sören Gebbert]

Hi Laurent,

2015-10-13 11:26 GMT+02:00 Laurent C. <lrntct at gmail.com>:
> Hi Sören,
>
> Thank you for your answer. I've made some tests with the second option
> and it seems to works well. It looks like I don't need to use
> .update() or .insert() before registering the RasterDataset list in
> the DB. Could you please confirm that it is unnecessary?

You don't need to perform any insert() or update() yourself, the
register function takes care of that.
You only need to set the name, mapset and timestamp for the
RasterDataset objects, put them into a list and pass them to the
register function.

Have a look at this code from the temporal aggregation:
https://trac.osgeo.org/grass/browser/grass/trunk/lib/python/temporal/aggregation.py#L287

Line 287 to 296

Best regards
Soeren

> Regards,
> Laurent
>
>
> 2015-10-09 22:45 GMT+01:00 Sören Gebbert <soerengebbert at googlemail.com>:
>> Hi Laurent,
>> please do not use the legacy r.timestamp module to set the time stamp
>> for maps. The feature to use time stamps set by r.timestamp was only
>> implemented, to migrate from old grass locations with time stamped
>> maps to the temporal framework approach more easily. I am not sure if
>> this works well with relative time.
>>
>> The easiest way is to generate a text file with name, start time and
>> end time. If you insist to avoid using text files, then generate a
>> list of RasterDataset[1] objects, set the time for these objects
>> (set_absolute_time() or set_relative_time()) and use
>> register_map_object_list() [2] to register them in a space time raster
>> dataset.
>>
>> [1] https://grass.osgeo.org/grass70/manuals/libpython/temporal.html#temporal.space_time_datasets.RasterDataset
>> [2] https://grass.osgeo.org/grass70/manuals/libpython/temporal.html#temporal.register.register_map_object_list
>>
>> Best regards
>> Soeren
>>
>> 2015-10-09 17:13 GMT+02:00 Laurent C. <lrntct at gmail.com>:
>>> Hello,
>>>
>>> I'm writing a module that generates raster maps and register them in
>>> newly created strds.
>>> The temporal type of the generated strds depends on the entry values
>>> of the module.
>>> I've seen in the documentation that
>>> register_maps_in_space_time_dataset() can read the timestamp from the
>>> GRASS raster, so my module is currently doing the following:
>>>  - writes maps
>>>  - assign timestamp, either absolute or relative with r.timestamp
>>>  - at the end, register all the generated maps from a list using
>>> register_maps_in_space_time_dataset()
>>>
>>> But I end up with the following error with relative time:
>>> File "/home/lo/Programación/t_sim_flood/gis.py", line 286, in
>>> register_maps_in_strds
>>>     strds_id, maps=map_lst_str, unit='seconds')
>>>   File "/usr/lib/grass71/etc/python/grass/temporal/register.py", line
>>> 289, in register_maps_in_space_time_dataset
>>>     statement += map.insert(dbif=dbif, execute=False)
>>>   File "/usr/lib/grass71/etc/python/grass/temporal/abstract_map_dataset.py",
>>> line 273, in insert
>>>     self.write_timestamp_to_grass()
>>>   File "/usr/lib/grass71/etc/python/grass/temporal/space_time_datasets.py",
>>> line 242, in write_timestamp_to_grass
>>>     self._convert_timestamp())
>>>   File "/usr/lib/grass71/etc/python/grass/temporal/abstract_map_dataset.py",
>>> line 124, in _convert_timestamp
>>>     start = datetime_to_grass_datetime_string(start_time)
>>>   File "/usr/lib/grass71/etc/python/grass/temporal/datetime_math.py",
>>> line 817, in datetime_to_grass_datetime_string
>>>     if dt.tzinfo is not None:
>>> AttributeError: 'NoneType' object has no attribute 'tzinfo'
>>>
>>> The grass timestamp are well written and are visible with r.info.
>>> If I give a start=0 to register_maps_in_space_time_dataset(), all the
>>> maps are registered in the strds without generating errors, but they
>>> all starts and ends at 0:
>>>  +-------------------- Relative time -----------------------------------------+
>>>  | Start time:................. 0
>>>  | End time:................... 0
>>>  | Relative time unit:......... seconds
>>>  | Granularity:................ 0
>>>  | Temporal type of maps:...... point
>>>  +-------------------- Spatial extent ----------------------------------------+
>>>
>>> And the raster timestamps are overwritten.
>>> I haven't tried yet with absolute type.
>>> How should I proceed? Is there a way to avoid generating a temporary
>>> text file to feed register_maps_in_space_time_dataset()?
>>>
>>> Regards,
>>> Laurent
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