t.info: add format option and JSON output support

general/g.parser/standard_option.c

@@ -88,7 +88,8 @@ static char *STD_OPT_STRINGS[] = {"G_OPT_UNDEFINED",
                                   "G_OPT_T_SUFFIX",
                                   "G_OPT_T_TYPE",
                                   "G_OPT_T_WHERE",
-                                  "G_OPT_T_SAMPLE"};
+                                  "G_OPT_T_SAMPLE",
+                                  "G_OPT_F_FORMAT"};
 
 struct Option *define_standard_option(const char *name)
 {

python/grass/script/utils.py

@@ -19,6 +19,8 @@
 
 from __future__ import annotations
 
+import datetime
+import json
 import os
 import shutil
 import locale
@@ -693,3 +695,32 @@ def append_random(name, suffix_length=None, total_length=None):
     # The following can be shorter with random.choices from Python 3.6.
     suffix = "".join(random.choice(allowed_chars) for _ in range(suffix_length))
     return "{name}_{suffix}".format(**locals())
+
+
+class TemporalJSONEncoder(json.JSONEncoder):
+    """Custom JSON encoder with datetime support for GRASS GIS.
+
+    Handles serialization of datetime objects to ISO 8601 format strings.
+    Can be used across GRASS modules that need JSON output with temporal data.
+
+    Example:
+
+    .. code-block:: pycon
+
+        >>> import json
+        >>> from datetime import datetime
+        >>> data = {"timestamp": datetime(2024, 1, 15, 10, 30)}
+        >>> json.dumps(data, cls=TemporalJSONEncoder)
+        '{"timestamp": "2024-01-15T10:30:00"}'
+    """
+
+    def default(self, obj):
+        """Override default JSON encoding for datetime objects.
+
+        :param obj: Object to encode
+        :return: ISO 8601 formatted string for datetime objects,
+                 or calls parent encoder for other types
+        """
+        if isinstance(obj, datetime.datetime):
+            return obj.isoformat()
+        return super().default(obj)

python/grass/temporal/Makefile

@@ -8,7 +8,7 @@ GDIR = $(PYDIR)/grass
 DSTDIR = $(GDIR)/temporal
 DSTDIRPLY = $(DSTDIR)/ply
 
-MODULES = ply/__init__ ply/lex ply/yacc base core abstract_dataset abstract_map_dataset abstract_space_time_dataset space_time_datasets open_stds factory gui_support list_stds register sampling metadata spatial_extent temporal_extent datetime_math temporal_granularity spatio_temporal_relationships unit_tests aggregation stds_export stds_import extract mapcalc univar_statistics temporal_topology_dataset_connector spatial_topology_dataset_connector c_libraries_interface temporal_algebra temporal_vector_algebra temporal_raster_base_algebra temporal_raster_algebra temporal_raster3d_algebra temporal_operator
+MODULES = ply/__init__ ply/lex ply/yacc base core abstract_dataset abstract_map_dataset abstract_space_time_dataset space_time_datasets open_stds factory gui_support list_stds register sampling metadata spatial_extent temporal_extent datetime_math temporal_granularity spatio_temporal_relationships unit_tests aggregation stds_export stds_import extract mapcalc univar_statistics temporal_topology_dataset_connector spatial_topology_dataset_connector c_libraries_interface temporal_algebra temporal_vector_algebra temporal_raster_base_algebra temporal_raster_algebra temporal_raster3d_algebra temporal_operator utils
 
 CLEAN_SUBDIRS = ply
 

python/grass/temporal/__init__.py

@@ -190,6 +190,7 @@
     print_gridded_dataset_univar_statistics,
     print_vector_dataset_univar_statistics,
 )
+from grass.script.utils import TemporalJSONEncoder
 
 __all__ = [
     "AbsoluteTemporalExtent",
@@ -253,6 +254,7 @@
     "TemporalAlgebraLexer",
     "TemporalAlgebraParser",
     "TemporalExtent",
+    "TemporalJSONEncoder",
     "TemporalOperatorLexer",
     "TemporalOperatorParser",
     "TemporalRaster3DAlgebraParser",

python/grass/temporal/abstract_dataset.py

@@ -12,11 +12,14 @@
 
 from __future__ import annotations
 
+import json
 from abc import ABCMeta, abstractmethod
 
 from .core import get_current_mapset, get_tgis_message_interface, init_dbif
 from .spatial_topology_dataset_connector import SpatialTopologyDatasetConnector
 from .temporal_topology_dataset_connector import TemporalTopologyDatasetConnector
+from grass.script.utils import TemporalJSONEncoder
+
 
 ###############################################################################
 
@@ -218,6 +221,54 @@ def print_info(self):
     def print_shell_info(self):
         """Print information about this class in shell style"""
 
+    def print_json(self) -> None:
+        """Print dataset metadata as JSON to stdout.
+
+        Outputs complete metadata in JSON format by merging all internal
+        data dictionaries. This automatically includes all metadata fields
+        without manual enumeration, ensuring parity with shell output.
+
+        The output can be parsed by any JSON-compatible tool or library.
+        """
+        data = self._to_json_dict()
+        print(json.dumps(data, cls=TemporalJSONEncoder, indent=4))
+
+    def _to_json_dict(self):
+        """Build a dictionary from internal metadata storage for JSON output.
+
+        Uses dict merging to automatically capture all metadata from the
+        internal D dictionaries. This approach ensures:
+
+        - Complete metadata coverage (no missing fields)
+        - No manual key enumeration required
+        - Automatic updates when new metadata fields are added
+        - Parity with print_shell_info() output
+
+        :return: Complete metadata dictionary ready for JSON serialization
+        """
+        # Merge all internal data dictionaries.
+        # Each component (base, temporal_extent, spatial_extent, metadata)
+        # stores its data in a D dict that gets merged here.
+        data = {}
+
+        # Add base metadata (id, name, mapset, creator, etc.)
+        if hasattr(self, "base") and hasattr(self.base, "D"):
+            data.update(self.base.D)
+
+        # Add temporal extent metadata (start_time, end_time, etc.)
+        if hasattr(self, "temporal_extent") and hasattr(self.temporal_extent, "D"):
+            data.update(self.temporal_extent.D)
+
+        # Add spatial extent metadata (north, south, east, west, etc.)
+        if hasattr(self, "spatial_extent") and hasattr(self.spatial_extent, "D"):
+            data.update(self.spatial_extent.D)
+
+        # Add general metadata (title, description, etc.)
+        if hasattr(self, "metadata") and hasattr(self.metadata, "D"):
+            data.update(self.metadata.D)
+
+        return data
+
     @abstractmethod
     def print_self(self):
         """Print the content of the internal structure to stdout"""

python/grass/temporal/abstract_map_dataset.py

@@ -341,6 +341,24 @@ def print_shell_info(self) -> None:
         if self.is_topology_build():
             self.print_topology_shell_info()
 
+    def _to_json_dict(self):
+        """Build a dictionary from internal metadata storage for JSON output.
+
+        Extends the base implementation by adding information about
+        space-time datasets that this map is registered in.
+
+        :return: Complete metadata dictionary including STDS registration info
+        """
+        # Get base metadata from parent class (uses dict-merge approach)
+        data = super()._to_json_dict()
+
+        # Add map-specific information: which STDSs is this map registered in?
+        datasets = self.get_registered_stds()
+        if datasets:
+            data["registered_datasets"] = sorted(list(datasets))
+
+        return data
+
     def insert(self, dbif=None, execute: bool = True):
         """Insert the map content into the database from the internal
         structure

python/grass/temporal/abstract_space_time_dataset.py

@@ -21,7 +21,10 @@ class that is the base class for all space time datasets.
 from pathlib import Path
 from grass.exceptions import FatalError
 
-from .abstract_dataset import AbstractDataset, AbstractDatasetComparisonKeyStartTime
+from .abstract_dataset import (
+    AbstractDataset,
+    AbstractDatasetComparisonKeyStartTime,
+)
 from .core import (
     get_current_mapset,
     get_sql_template_path,
@@ -178,6 +181,24 @@ def print_shell_info(self) -> None:
         self.spatial_extent.print_shell_info()
         self.metadata.print_shell_info()
 
+    def _to_json_dict(self):
+        """Build a dictionary from internal metadata storage for JSON output.
+
+        Extends the base implementation by adding computed fields that are
+        present in shell output but not stored in the D dictionaries.
+        For example, semantic_labels is fetched on-the-fly via SQL.
+
+        :return: Complete metadata dictionary with computed fields included
+        """
+        data = super()._to_json_dict()
+
+        # Add computed fields from metadata that are in shell output
+        # but not in metadata.D (fetched on-the-fly via SQL)
+        if hasattr(self.metadata, "get_semantic_labels"):
+            data["semantic_labels"] = self.metadata.get_semantic_labels()
+
+        return data
+
     def print_history(self) -> None:
         """Print history information about this class in human readable
         shell style

python/grass/temporal/utils.py

@@ -0,0 +1,14 @@
+"""Utility functions and classes for the temporal framework.
+
+(C) 2025 by the GRASS Development Team
+This program is free software under the GNU General Public
+License (>=v2). Read the file COPYING that comes with GRASS
+for details.
+
+:authors: GRASS Development Team
+"""
+
+# Re-export from canonical location for backward compatibility
+from grass.script.utils import TemporalJSONEncoder
+
+__all__ = ["TemporalJSONEncoder"]

temporal/t.info/t.info.py

@@ -38,6 +38,12 @@
 # % options: strds, str3ds, stvds, raster, raster_3d, vector
 # %end
 
+# %option G_OPT_F_FORMAT
+# % options: plain,json,shell
+# % descriptions: plain;Human readable text output;shell;Shell script style text output;json;JSON (JavaScript Object Notation)
+# % guisection: Print
+# %end
+
 # %flag
 # % key: g
 # % description: Print in shell script style
@@ -65,6 +71,7 @@ def main():
 
     name = options["input"]
     type_ = options["type"]
+    format_ = options["format"]
     shellstyle = flags["g"]
     system = flags["d"]
     history = flags["h"]
@@ -119,7 +126,9 @@ def main():
         dataset.print_history()
         return
 
-    if shellstyle:
+    if format_ == "json":
+        dataset.print_json()
+    elif format_ == "shell" or shellstyle:
         dataset.print_shell_info()
     else:
         dataset.print_info()