Band references implementation

[landam]

This PR implements basic functionality related to image collections (https://developers.google.com/earth-engine/tutorial_api_04).

It's dedicated for testing, various improvements are still planned.

Development has been supported mundialis GmbH & Co.KG

How to test

1. Create GRASS location, download sample data

./bin.x86_64-pc-linux-gnu/grass77 -c EPSG:32633 /tmp/image-collection-test
> g.extension ext=i.sentinel
> i.sentinel.download settings=sentinel.txt uuid=a12d7d6d-0c41-4f5e-8789-7e9cff3529df output=/tmp
> i.sentinel.import input=/tmp

2. Create STRDS

> t.create test title=test description=test

3. Register maps from input file

3.a Create input file

(note that similar functionality is planned to be implemented in i.sentinel.import)

Run PyGRASS script in order to create input file for t.register:

#!/usr/bin/env python

from grass.pygrass.raster import RasterRow
from grass.pygrass.gis import Mapset

from datetime import datetime

def list_rasters():
    m = Mapset()
    return m.glist('raster')

def do_list():
    for name in list_rasters():
        with RasterRow(name) as rast:
            band = rast.name.split('_', -1)[-1].lstrip('B').lstrip('0')
            band_ref = "S2_{}".format(band)

            date = datetime.strptime(
                rast.name.split('_')[1],
                '%Y%m%dT%H%M%S'
            )
            print ('{}|{}|{}'.format(name, date, band_ref))

if __name__ == "__main__":
    do_list()

Expected result:

T33UYP_20190331T094039_B01|2019-03-31 09:40:39|S2_1
T33UYP_20190331T094039_B10|2019-03-31 09:40:39|S2_10
T33UYP_20190331T094039_B02|2019-03-31 09:40:39|S2_2
T33UYP_20190331T094039_B05|2019-03-31 09:40:39|S2_5
T33UYP_20190331T094039_B11|2019-03-31 09:40:39|S2_11
T33UYP_20190331T094039_B08|2019-03-31 09:40:39|S2_8
T33UYP_20190331T094039_B12|2019-03-31 09:40:39|S2_12
T33UYP_20190331T094039_B8A|2019-03-31 09:40:39|S2_8A
T33UYP_20190331T094039_B06|2019-03-31 09:40:39|S2_6
T33UYP_20190331T094039_B04|2019-03-31 09:40:39|S2_4
T33UYP_20190331T094039_B03|2019-03-31 09:40:39|S2_3
T33UYP_20190331T094039_B09|2019-03-31 09:40:39|S2_9

Redirect output into file:

python grass_image_collections_file.py > /tmp/t_register.txt

3.b Register sample raster data into STDS from input file

t.register input=test file=/tmp/t_register.txt

4. Quick band reference filtering tests

Commands like:

> t.rast.list test
> g.region rast=T33UYP_20190331T094039_B01
> t.rast.univar test

should process all raster maps registered in space time dataset.

Now let's try to set up band reference filter (first band only):

> t.rast.list test:S2_1
name|mapset|start_time|end_time
T33UYP_20190331T094039_B01|PERMANENT|2019-03-31 09:40:39|None
> t.rast.univar test:S2_1
id|start|end|mean|min|max|mean_of_abs|stddev|variance|coeff_var|sum|null_cells|cells|non_null_cells
T33UYP_20190331T094039_B01@PERMANENT|2019-03-31 09:40:39|None|784.356813580579|0|4309|784.356813580579|677.557914588275|459084.727621212|86.383888411096|2626732533|0|3348900|3348900

5. Metadata

Raster type:

t.info T33UYP_20190331T094039_B01 type=raster
...
 +-------------------- Metadata information ----------------------------------+
 | Band reference:............. S2B_1
...

t.info T33UYP_20190331T094039_B01 type=raster -g
...
band_reference=S2_1
...

STRDS type:

t.info test
...
+-------------------- Metadata information ----------------------------------+
...
 | Number of registered bands:. 13
...

t.info test -g
...
number_of_bands=13
...

Known limits

• band reference can be assigned only to 2D raster map (3D raster maps and vector maps are currently not supported)
• raster maps with band reference can be registered only in STRDS created in TGIS DB 3 (so with GRASS including this PR)
• r.info does not print band reference info
• only very limited band references included (Sentinel2, Landsat7, Landsat8)
• tests for temporal lib are missing