[GRASS-user] Questions on TGRASS; t.rast.gapfill , GRASS 71

[Sören Gebbert]

Hi Sajid,
until today, t.rast.gapfill did not support interpolation by granularity.
However, please try revision r64651 in grass7.1 trunk. This feature
has now been implemented and should work as you would expect.
Of course, heavily testing is still needed.

I am still investigating the case when no gaps are found using the
where condition.

Best regards
Soeren

2015-02-05 19:23 GMT+01:00 sajid pareeth <spareeth at gmail.com>:
> Hi
> I am trying to use the module "t.rast.gapfill" to fill the gaps in my
> temporal datasets. I have couple of doubts on getting my tasks done.
>
> I am using GRASS 71 svn, latest.
>
> ##Q1:
>
> In my temporal data , there are multiple continuous gaps. In this case, I am
> not getting the interpolated results. Please check the below work flow:
>
> r.mapcalc expr="map1 = 1" --o
> r.mapcalc expr="map2 = 3" --o
> r.mapcalc expr="map3 = 5" --o
> r.mapcalc expr="map4 = 7" --o
> r.mapcalc expr="map5 = 9" --o
> t.register type=raster maps=map1 start=2012-08-20 end=2012-08-21 --o
> t.register type=raster maps=map2 start=2012-08-22 end=2012-08-23 --o
> t.register type=raster maps=map3 start=2012-08-25 end=2012-08-26 --o
> t.register type=raster maps=map4 start=2012-08-29 end=2012-08-30 --o
> t.register type=raster maps=map5 start=2012-09-03 end=2012-09-04 --o
> t.create type=strds temporaltype=absolute output=mapT1 title="test for all
> the gaps filled together" description="test for all the gaps filled
> together"
> t.register type=raster input=mapT1 maps=map1,map2,map3,map4,map5 --o
> t.rast.list input=mapT1 columns=name,start_time,min,max
> t.rast.list input=mapT1 method=gran
> id|name|mapset|start_time|end_time|interval_length|distance_from_begin
> map1 at testtgrass|map1|testtgrass|2012-08-20 00:00:00|2012-08-21
> 00:00:00|1.0|0.0
> None|None|None|2012-08-21 00:00:00|2012-08-22 00:00:00|1.0|1.0
> map2 at testtgrass|map2|testtgrass|2012-08-22 00:00:00|2012-08-23
> 00:00:00|1.0|2.0
> None|None|None|2012-08-23 00:00:00|2012-08-24 00:00:00|1.0|3.0
> None|None|None|2012-08-24 00:00:00|2012-08-25 00:00:00|1.0|4.0
> map3 at testtgrass|map3|testtgrass|2012-08-25 00:00:00|2012-08-26
> 00:00:00|1.0|5.0
> None|None|None|2012-08-26 00:00:00|2012-08-27 00:00:00|1.0|6.0
> None|None|None|2012-08-27 00:00:00|2012-08-28 00:00:00|1.0|7.0
> None|None|None|2012-08-28 00:00:00|2012-08-29 00:00:00|1.0|8.0
> map4 at testtgrass|map4|testtgrass|2012-08-29 00:00:00|2012-08-30
> 00:00:00|1.0|9.0
> None|None|None|2012-08-30 00:00:00|2012-08-31 00:00:00|1.0|10.0
> None|None|None|2012-08-31 00:00:00|2012-09-01 00:00:00|1.0|11.0
> None|None|None|2012-09-01 00:00:00|2012-09-02 00:00:00|1.0|12.0
> None|None|None|2012-09-02 00:00:00|2012-09-03 00:00:00|1.0|13.0
> map5 at testtgrass|map5|testtgrass|2012-09-03 00:00:00|2012-09-04
> 00:00:00|1.0|14.0
>
> # Doing the gapfill:
> t.rast.gapfill input=mapT1 base=gap
> t.rast.list input=mapT1 method=gran
> id|name|mapset|start_time|end_time|interval_length|distance_from_begin
> map1 at testtgrass|map1|testtgrass|2012-08-20 00:00:00|2012-08-21
> 00:00:00|1.0|0.0
> gap_10 at testtgrass|gap_10|testtgrass|2012-08-21 00:00:00|2012-08-22
> 00:00:00|1.0|1.0
> map2 at testtgrass|map2|testtgrass|2012-08-22 00:00:00|2012-08-23
> 00:00:00|1.0|2.0
> gap_11 at testtgrass|gap_11|testtgrass|2012-08-23 00:00:00|2012-08-24
> 00:00:00|1.0|3.0
> gap_11 at testtgrass|gap_11|testtgrass|2012-08-24 00:00:00|2012-08-25
> 00:00:00|1.0|4.0
> map3 at testtgrass|map3|testtgrass|2012-08-25 00:00:00|2012-08-26
> 00:00:00|1.0|5.0
> gap_12 at testtgrass|gap_12|testtgrass|2012-08-26 00:00:00|2012-08-27
> 00:00:00|1.0|6.0
> gap_12 at testtgrass|gap_12|testtgrass|2012-08-27 00:00:00|2012-08-28
> 00:00:00|1.0|7.0
> gap_12 at testtgrass|gap_12|testtgrass|2012-08-28 00:00:00|2012-08-29
> 00:00:00|1.0|8.0
> map4 at testtgrass|map4|testtgrass|2012-08-29 00:00:00|2012-08-30
> 00:00:00|1.0|9.0
> gap_13 at testtgrass|gap_13|testtgrass|2012-08-30 00:00:00|2012-08-31
> 00:00:00|1.0|10.0
> gap_13 at testtgrass|gap_13|testtgrass|2012-08-31 00:00:00|2012-09-01
> 00:00:00|1.0|11.0
> gap_13 at testtgrass|gap_13|testtgrass|2012-09-01 00:00:00|2012-09-02
> 00:00:00|1.0|12.0
> gap_13 at testtgrass|gap_13|testtgrass|2012-09-02 00:00:00|2012-09-03
> 00:00:00|1.0|13.0
> map5 at testtgrass|map5|testtgrass|2012-09-03 00:00:00|2012-09-04
> 00:00:00|1.0|14.0
>
> For example; between 2012-08-29 and 2012-09-03 there are 4 days of gap, but
> the gap filling is providing the same image at all the 4 gaps. It seems to
> be generating only one image between two valid temporal images, no matter
> how long the gap is!!
>
> So is the gap filling will work only for one gap between 2 valid temporal
> images?
>
>
> ###2.
>
> When I try to do gap fill with the "where" condition, I am getting no
> results in some cases.
> For example when I try:
>
> t.rast.gapfill input=mapT1 where="start_time = '2012-08-21 00:00:00'"
> base=gap
> No gaps found
>
> OR when I try;
>
> t.rast.gapfill input=mapT1 where="start_time > '2012-08-20 00:00:00'"
> base=gap
>
> It misses the first gap and fills the other gap, see below:
>
> t.rast.list input=mapT1 method=gran
> id|name|mapset|start_time|end_time|interval_length|distance_from_begin
> map1 at testtgrass|map1|testtgrass|2012-08-20 00:00:00|2012-08-21
> 00:00:00|1.0|0.0
> None|None|None|2012-08-21 00:00:00|2012-08-22 00:00:00|1.0|1.0
> map2 at testtgrass|map2|testtgrass|2012-08-22 00:00:00|2012-08-23
> 00:00:00|1.0|2.0
> gap_8 at testtgrass|gap_8|testtgrass|2012-08-23 00:00:00|2012-08-24
> 00:00:00|1.0|3.0
> gap_8 at testtgrass|gap_8|testtgrass|2012-08-24 00:00:00|2012-08-25
> 00:00:00|1.0|4.0
> map3 at testtgrass|map3|testtgrass|2012-08-25 00:00:00|2012-08-26
> 00:00:00|1.0|5.0
> gap_9 at testtgrass|gap_9|testtgrass|2012-08-26 00:00:00|2012-08-27
> 00:00:00|1.0|6.0
> gap_9 at testtgrass|gap_9|testtgrass|2012-08-27 00:00:00|2012-08-28
> 00:00:00|1.0|7.0
> gap_9 at testtgrass|gap_9|testtgrass|2012-08-28 00:00:00|2012-08-29
> 00:00:00|1.0|8.0
> map4 at testtgrass|map4|testtgrass|2012-08-29 00:00:00|2012-08-30
> 00:00:00|1.0|9.0
> gap_10 at testtgrass|gap_10|testtgrass|2012-08-30 00:00:00|2012-08-31
> 00:00:00|1.0|10.0
> gap_10 at testtgrass|gap_10|testtgrass|2012-08-31 00:00:00|2012-09-01
> 00:00:00|1.0|11.0
> gap_10 at testtgrass|gap_10|testtgrass|2012-09-01 00:00:00|2012-09-02
> 00:00:00|1.0|12.0
> gap_10 at testtgrass|gap_10|testtgrass|2012-09-02 00:00:00|2012-09-03
> 00:00:00|1.0|13.0
> map5 at testtgrass|map5|testtgrass|2012-09-03 00:00:00|2012-09-04
> 00:00:00|1.0|14.0
>
> Here it works if I give one day before the actual valid temporal image in
> the where condition. So if I give "start_time > '2012-08-19 00:00:00'", the
> first gap will also get filled. But It would be great if we can query on the
> missing dates/time.
>
> All suggestions welcome.
>
> Thanks in advance
>
> Regards
>
> Sajid
>
> --
>
> http://gis.cri.fmach.it/pareeth/
>
> Fondazione Edmund Mach
> Research and Innovation Centre
> GIS and Remote Sensing Unit/Limnology and River ecology
> Via Mach 1, 38010 San Michele all'Adige (TN) - Italy
> Phone +39 461 615 669
> spareeth at gmail.com
> sajid.pareeth at fmach.it
> skype: spareeth
>
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