temporal: t.rast.aggregate: add -e flag to extend existing STRDS by Sourish-spc · Pull Request #7223 · OSGeo/grass

Sourish-spc · 2026-03-27T07:32:30Z

Description

This PR adds support for extending an existing Space Time Raster Dataset (STRDS) in t.rast.aggregate by introducing a new -e flag, following the same pattern implemented in #3798 for t.rast.neighbors.

Changes

Added -e flag (Extend existing space time raster dataset) to module interface
Modified STRDS creation logic to open existing STRDS when -e flag is set instead of always creating a new one
Added history update via update_command_string() when extending existing STRDS
Added test test_extend_existing_strds to existing test suite

Usage

First run — creates new STRDS:
t.rast.aggregate input=daily_rain output=monthly_rain granularity="1 month" method=average basename=result

Second run — extends existing STRDS:
t.rast.aggregate input=daily_rain output=monthly_rain granularity="1 month" method=average basename=result_new -e

In stds_import.py, the finally block used the deprecated 'gisdbase' option when calling g.mapset to switch back to the original location. This caused a deprecation warning on every t.rast.import run with the project parameter. Replaced 'gisdbase' with 'dbase' to match the current g.mapset API. Fixes OSGeo#4231

temporal/t.rast.aggregate/t.rast.aggregate.py

temporal/t.rast.aggregate/testsuite/test_aggregation_absolute.py

ninsbl

Please also install pre-commit in your local working directory to avoid CI runs for formalities...

ninsbl · 2026-03-27T08:51:44Z

temporal/t.rast.aggregate/t.rast.aggregate.py

+        gs.fatal(
+            _(
+                "Space time raster dataset <%s> does not exist. "
+                "Cannot extend a non-existing dataset."
+            )
+            % output
+        )


Personally, I do not think a fatal error should be thrown here. I would say, a warning at best. In any case, this part should be consistent across all temporal tools that receive the e-flag.

Updated: changed fatal error to warning and fall back to creating new STRDS when dataset doesn't exist.

Adds support for extending an existing Space Time Raster Dataset by running t.rast.aggregate with the -e flag. This allows recurring workflows to append new aggregated results to an existing STRDS without deleting previous data. See OSGeo#3427

wenzeslaus · 2026-03-28T04:07:07Z

temporal/t.rast.aggregate/testsuite/test_aggregation_absolute.py

+        # Verify STRDS was extended
+        lister = SimpleModule("t.rast.list", input="B", columns="name", flags="u")
+        self.runModule(lister)
+        self.assertIn("b_ext", lister.outputs.stdout)


This only checks that some map with "b_ext" in the name exists. It doesn't verify the original maps are still present, that the STRDS wasn't just overwritten, and/or the total map count.

Thank you for the review. The test has been strengthened to also verify that original maps are still present and the total map count increased after extending.

wenzeslaus · 2026-03-28T04:11:36Z

temporal/t.rast.aggregate/t.rast.aggregate.py

+        if output_exists:
+            output_strds.update_command_string(dbif=dbif)


Does this make sense when overwriting?

Good point, iI did not really think about it. It may make sense in any case. I did not check the behavior. Updates of the STDS should be written to the history I`ld say, which is what update_command_string does. The command should not be duplicated in the history though. That should be checked...

Updated the condition to if not output_exists or extend to avoid duplicating the command string in history when overwriting, while still updating it correctly when extending.

wenzeslaus · 2026-03-28T04:12:08Z

temporal/t.rast.aggregate/t.rast.aggregate.py


 if __name__ == "__main__":
    options, flags = gs.parser()
+


Please, review your code, including the PR changes.

Thank you for the review. The extra blank line has been removed in the latest commit.

wenzeslaus · 2026-03-28T04:14:07Z

temporal/t.rast.aggregate/t.rast.aggregate.py

+        if not output_exists or (overwrite and not extend):
+            temporal_type, semantic_type, title, description = sp.get_initial_values()
+            output_strds = tgis.open_new_stds(
+                output,
+                "strds",
+                temporal_type,
+                title,
+                description,
+                semantic_type,
+                dbif,
+                overwrite,
+            )
+        elif output_exists and extend:
+            output_strds = tgis.open_old_stds(output, "strds", dbif)


What happens when "else"? Or is there a condition which I don't see. Perhaps worth commenting on if that's the case.

I noticed that in the.rast.neighbors too, where this is likely copied from. So It should be addressed there in a different PR too. Given that the possibility to extend existing STDS would be useful in multiple temporal tools, maybe a extend_if_exists (or something like that) library function would make sense, that returns either a new or exiting STDS!? @wenzeslaus what do you think?

Maybe enhance and use

grass/python/grass/temporal/open_stds.py

Line 91 in 65a1515

def check_new_stds(name, type, dbif=None, overwrite: bool = False):

?

Refactored the extend logic into check_new_stds in open_stds.py as a reusable library function with an extend parameter. The else case is now handled there: if -e is set and STRDS does not exist, it silently creates a new one (extend-if-exists behavior).

Hi, an sorry for possibly putting you on a slightly wrong track with enhancing check_new_stds . That function should probably stay as is.
What in general is needed is 1) a function that checks if output STDS can be opened as requested (new or existing for update, e.g. check_open_output_stds). That should be minimal (not creating or opening) and run before main processing starts. And 2), after main processing succeeded, the output STDS should be opened or created so produced maps can be registered (e.g. open_output_stds).

wenzeslaus · 2026-03-28T04:18:13Z

temporal/t.rast.aggregate/t.rast.aggregate.py

+    if extend and not output_exists:
+        gs.warning(
+            _(
+                "Space time raster dataset <%s> does not exist. "
+                "Cannot extend a non-existing dataset."
+            )
+            % output
+        )
+        extend = False  # fall back to creating new STRDS


The warning does not make sense to me. Either -e is "extend if already exist" (no error or warning needed) or "extend existing" (so error on non-existence). The first option is sort of append mode; we have that elsewhere.

Agreed. That said, the confusion is my fault as I have not been explicit.
Personally, I would prefer "extend-if-exists" behavior, as it is more graceful, but I have no strong opinion here...

Removed the warning and fallback. Now using extend-if-exists behavior: if the STRDS doesn't exist, it just creates a new one silently.

github-actions bot added temporal Related to temporal data processing Python Related code is in Python libraries module tests Related to Test Suite labels Mar 27, 2026

Sourish-spc force-pushed the temporal/t.rast.aggregate-extend-mode branch from 7ee4adc to 9b2110e Compare March 27, 2026 07:45

github-actions bot reviewed Mar 27, 2026

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temporal/t.rast.aggregate/t.rast.aggregate.py Outdated Show resolved Hide resolved

temporal/t.rast.aggregate/testsuite/test_aggregation_absolute.py Outdated Show resolved Hide resolved

ninsbl requested changes Mar 27, 2026

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Sourish-spc added 9 commits March 27, 2026 12:51

fix: resolve ruff linting issues

9b2110e

fix: resolve remaining ruff linting issues

a39bdee

Merge branch 'main' into temporal/t.rast.aggregate-extend-mode

3f76909

fix: resolve extra line issue

e0de432

fix: add trailing newline at end of files

6ec7ac4

fix: resolve extra line issue

ca3f87e

fix: add trailing newline at end of files

d878245

fix: use warning instead of fatal when extending non-existing STRDS

1ca0f6e

wenzeslaus requested changes Mar 28, 2026

View reviewed changes

Sourish-spc added 5 commits March 29, 2026 10:41

temporal: refactor extend logic into check_new_stds library function

d73d2a5

Merge branch 'main' into temporal/t.rast.aggregate-extend-mode

36700a4

temporal: strengthen test for -e flag to verify extend behavior

75d75b0

temporal: remove extra blank line in __main__ block

0d65b33

temporal: fix metadata overwrite bug on extend and resolve ruff RUF052

58f6d4b

		if output_exists:
		output_strds.update_command_string(dbif=dbif)

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Sourish-spc commented Mar 27, 2026

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