[GRASS-user] How to sample an STVDS based on an STRDS

GRASS GRASS user
1

Hi,

I'm fairly new to the temporal features in GRASS. I think I'm looking for the inverse of t.rast.aggregate.ds - that is, I have an STRDS with arbitrary intervals (roughly, 24 day windows moving about every 6 days). I have an STVDS with daily data. I'd like to aggregate the daily STVDS to match the STRDS.

I can do this using t.sample, parse that, and aggregate. But this seems to be a fair amount of manual work, and it looks like GRASS abstracts much of this if I were going the other way - subsetting a STRDS based on an STVDS.

Is there a simple way to do this in GRASS - i.e. Is there a command I'm missing or mis-understanding? Or does subsetting vectors take more work because there is no analog to t.rast.aggregate.ds?

Thanks,

  -k.

2

Dear Ken,
there is no functionality for vector aggregation available in GRASS
GIS Temporal Framework. Dependent on your STVDS, maybe you can convert
it into a STRDS by using v.to.rast for each vector layer and then
organize the resulting raster layers in a new STRDS.

Best regards
Sören

2017-12-05 14:00 GMT+01:00 Ken Mankoff <mankoff@gmail.com>:

Hi,

I'm fairly new to the temporal features in GRASS. I think I'm looking for the inverse of t.rast.aggregate.ds - that is, I have an STRDS with arbitrary intervals (roughly, 24 day windows moving about every 6 days). I have an STVDS with daily data. I'd like to aggregate the daily STVDS to match the STRDS.

I can do this using t.sample, parse that, and aggregate. But this seems to be a fair amount of manual work, and it looks like GRASS abstracts much of this if I were going the other way - subsetting a STRDS based on an STVDS.

Is there a simple way to do this in GRASS - i.e. Is there a command I'm missing or mis-understanding? Or does subsetting vectors take more work because there is no analog to t.rast.aggregate.ds?

Thanks,

  -k.

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3

Hi Sören,

On 2017-12-05 at 13:12, Sören Gebbert <soerengebbert@googlemail.com> wrote:

there is no functionality for vector aggregation available in GRASS
GIS Temporal Framework.

OK - good to know I'm not missing anything.

Dependent on your STVDS, maybe you can convert it into a STRDS by
using v.to.rast for each vector layer and then organize the resulting
raster layers in a new STRDS.

It would not be efficient to convert my 19-point STVDS's to rasters which have 100s of 1000s of cells.

It shouldn't be too hard to use the output of t.sample to generate aggregates myself. I'll take this route.

Thanks,

  -k.