t.snap(1grass)

📦
version 8.5.0 · 10 versions
, in alpine 3.24, ubuntu stonking

✨ t.snap — GRASS User's Manual 💖

okay so bestie, welcome to the federal documentation of snapping 💅 this is t.snap from the GRASS User's Manual, and yes it's a whole vibe.

🌸 NAME 🌸

t.snap — snaps temporally the maps of a space time dataset. fr fr that's the whole job description 🫶

🎀 KEYWORDS 🎀

temporal, time management, snapping, time

🌈 SYNOPSIS 🌈

t.snap
t.snap --help
t.snap input=name  [type=name]   [--help]  [--verbose]  [--quiet]
[--ui]

⭐ Flags ✨

  • --help — prints you a lil usage summary, no cap
  • --verbose — verbose module output, she's chatty 💬
  • --quiet — quiet module output, she's giving mysterious 🤫
  • --ui — force launching the GUI dialog, pop off queen 👑

🦋 Parameters 🦋

  • input=name [required] — name of an existing space time dataset. you literally cannot skip this one, she's mandatory 💀
  • type=name — type of the input space time dataset
    • Options: strds, stvds, str3ds
    • Default: strds

💜 DESCRIPTION 💜

t.snap is designed to convert time instances of maps into time intervals, or to create valid temporal topologies for space time datasets. Raster, 3D raster and vector space time datasets are all supported, with absolute and relative time. iconic, versatile, we love to see it ✨

So what this module actually does: it "snaps" the end time of each registered map of a space time dataset to the start time of the map that is the temporal nearest neighbour in the future. Basically she goes "hey you, end where the next one starts" 👯‍♀️

⚠️ Warning bestie: maps with equal time stamps are NOT modified and must be removed or modified to create a valid temporal topology. she will not touch them, periodt.

And if the last map in the space time dataset is a time instance? Then the granularity of the space time dataset gets used to create the time interval. the dataset's own granularity comes in clutch 💅

🔥 EXAMPLE 🔥

So picture this: a raster space time dataset gets created from precipitation maps for 2012, using absolute time in a space time raster dataset with an increment of one month. And at the end we snap the created time instances, which results in time intervals. main character arc honestly 🌟

# Generate data
t.create type=strds temporaltype=absolute \
         output=precipitation_monthly \
         title="Monthly precipitation" \
         description="Dataset with monthly precipitation"
t.register type=raster input=precipitation_monthly \
           maps=`g.list type=raster pattern="2012*precip" sep=comma` \
           start=2012-01-01 increment="1 months"
# please take attention to "Temporal type of maps" value
t.info type=strds input=precipitation_monthly
 +-------------------- Space Time Raster Dataset -----------------------------+
 |                                                                            |
 +-------------------- Basic information -------------------------------------+
 | Id: ........................ precipitation_monthly@climate_2009_2012
 | Name: ...................... precipitation_monthly
 | Mapset: .................... climate_2009_2012
 | Creator: ................... lucadelu
 | Temporal type: ............. absolute
 | Creation time: ............. 2014-11-28 15:52:30.801148
 | Modification time:.......... 2014-11-28 15:53:18.430773
 | Semantic type:.............. mean
 +-------------------- Absolute time -----------------------------------------+
 | Start time:................. 2012-01-01 00:00:00
 | End time:................... 2012-12-01 00:00:00
 | Granularity:................ 1 month
 | Temporal type of maps:...... point
 +-------------------- Spatial extent ----------------------------------------+
 | North:...................... 320000.0
 | South:...................... 10000.0
 | East:.. .................... 935000.0
 | West:....................... 120000.0
 | Top:........................ 0.0
 | Bottom:..................... 0.0
 +-------------------- Metadata information ----------------------------------+
 | Raster register table:...... raster_map_register_282454f66ff5455299526ec3c1db7362
 | North-South resolution min:. 500.0
 | North-South resolution max:. 500.0
 | East-west resolution min:... 500.0
 | East-west resolution max:... 500.0
 | Minimum value min:.......... 0.0
 | Minimum value max:.......... 95.58169
 | Maximum value min:.......... 132.413284
 | Maximum value max:.......... 356.502949
 | Aggregation type:........... None
 | Number of registered maps:.. 12
 |
 | Title:
 | Monthly precipitation
 | Description:
 | Dataset with monthly precipitation
 | Command history:
 | # 2014-11-28 15:52:30
 | t.create type="strds" temporaltype="absolute"
 |     output="precipitation_monthly" title="Monthly precipitation"
 |     description="Dataset with monthly precipitation"
 | # 2014-11-28 15:53:18
 | t.register type="rast" input="precipitation_monthly"
 |     maps="2012_01_precip,2012_02_precip, ... ,2012_11_precip,2012_12_precip"
 |     start="2012-01-01" increment="1 months"
 |
 +----------------------------------------------------------------------------+
# you can see that end time is not set
t.rast.list input=precipitation_monthly
name|mapset|start_time|end_time
2012_01_precip|climate_2009_2012|2012-01-01 00:00:00|None
2012_02_precip|climate_2009_2012|2012-02-01 00:00:00|None
2012_03_precip|climate_2009_2012|2012-03-01 00:00:00|None
2012_04_precip|climate_2009_2012|2012-04-01 00:00:00|None
2012_05_precip|climate_2009_2012|2012-05-01 00:00:00|None
2012_06_precip|climate_2009_2012|2012-06-01 00:00:00|None
2012_07_precip|climate_2009_2012|2012-07-01 00:00:00|None
2012_08_precip|climate_2009_2012|2012-08-01 00:00:00|None
2012_09_precip|climate_2009_2012|2012-09-01 00:00:00|None
2012_10_precip|climate_2009_2012|2012-10-01 00:00:00|None
2012_11_precip|climate_2009_2012|2012-11-01 00:00:00|None
2012_12_precip|climate_2009_2012|2012-12-01 00:00:00|None
t.snap type=strds input=precipitation_monthly
# please take attention to "Temporal type of maps" value again
t.info type=strds input=precipitation_monthly
 +-------------------- Space Time Raster Dataset -----------------------------+
 |                                                                            |
 +-------------------- Basic information -------------------------------------+
 | Id: ........................ precipitation_monthly@climate_2009_2012
 | Name: ...................... precipitation_monthly
 | Mapset: .................... climate_2009_2012
 | Creator: ................... lucadelu
 | Temporal type: ............. absolute
 | Creation time: ............. 2014-11-28 15:52:30.801148
 | Modification time:.......... 2014-11-28 15:54:28.739905
 | Semantic type:.............. mean
 +-------------------- Absolute time -----------------------------------------+
 | Start time:................. 2012-01-01 00:00:00
 | End time:................... 2013-01-01 00:00:00
 | Granularity:................ 1 month
 | Temporal type of maps:...... interval
 +-------------------- Spatial extent ----------------------------------------+
 | North:...................... 320000.0
 | South:...................... 10000.0
 | East:.. .................... 935000.0
 | West:....................... 120000.0
 | Top:........................ 0.0
 | Bottom:..................... 0.0
 +-------------------- Metadata information ----------------------------------+
 | Raster register table:...... raster_map_register_282454f66ff5455299526ec3c1db7362
 | North-South resolution min:. 500.0
 | North-South resolution max:. 500.0
 | East-west resolution min:... 500.0
 | East-west resolution max:... 500.0
 | Minimum value min:.......... 0.0
 | Minimum value max:.......... 95.58169
 | Maximum value min:.......... 132.413284
 | Maximum value max:.......... 356.502949
 | Aggregation type:........... None
 | Number of registered maps:.. 12
 |
 | Title:
 | Monthly precipitation
 | Description:
 | Dataset with monthly precipitation
 | Command history:
 | # 2014-11-28 15:52:30
 | t.create type="strds" temporaltype="absolute"
 |     output="precipitation_monthly" title="Monthly precipitation"
 |     description="Dataset with monthly precipitation"
 | # 2014-11-28 15:53:18
 | t.register type="rast" input="precipitation_monthly"
 |     maps="2012_01_precip,2012_02_precip, ... ,2012_11_precip,2012_12_precip"
 |     start="2012-01-01" increment="1 months"
 | # 2014-11-28 15:54:28
 | t.snap type="strds" input="precipitation_monthly"
 |
 +----------------------------------------------------------------------------+
# now instead end time is set
t.rast.list input=precipitation_daily
2012_01_precip|climate_2009_2012|2012-01-01 00:00:00|2012-02-01 00:00:00
2012_02_precip|climate_2009_2012|2012-02-01 00:00:00|2012-03-01 00:00:00
2012_03_precip|climate_2009_2012|2012-03-01 00:00:00|2012-04-01 00:00:00
2012_04_precip|climate_2009_2012|2012-04-01 00:00:00|2012-05-01 00:00:00
2012_05_precip|climate_2009_2012|2012-05-01 00:00:00|2012-06-01 00:00:00
2012_06_precip|climate_2009_2012|2012-06-01 00:00:00|2012-07-01 00:00:00
2012_07_precip|climate_2009_2012|2012-07-01 00:00:00|2012-08-01 00:00:00
2012_08_precip|climate_2009_2012|2012-08-01 00:00:00|2012-09-01 00:00:00
2012_09_precip|climate_2009_2012|2012-09-01 00:00:00|2012-10-01 00:00:00
2012_10_precip|climate_2009_2012|2012-10-01 00:00:00|2012-11-01 00:00:00
2012_11_precip|climate_2009_2012|2012-11-01 00:00:00|2012-12-01 00:00:00
2012_12_precip|climate_2009_2012|2012-12-01 00:00:00|2013-01-01 00:00:00

queen snapped and the end times appeared 💅✨

👀 SEE ALSO 👀

t.shift, t.create, t.register

the whole temporal friend group honestly 🫶

👑 AUTHOR 👑

Sören Gebbert, Thünen Institute of Climate-Smart Agriculture. we stan 🌾

🧚 SOURCE CODE 🧚

Available at: t.snap source code (history)

Latest change: Thursday Dec 18 07:11:47 2025 in commit: cf870a5e49fd2643a55de543467edf5c2e61d640

Main index | Temporal index | Topics index | Keywords index | Graphical index | Full index

and that's the whole page bestie 🎀 this was the GRASS t.snap(1grass) manual, straight out of GRASS 8.5.0, © 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual. mwah, go snap something 💖🦋🌈

📦 where this page comes from