[GRASS-user] temporal dataset : register maps from other mapsets

GRASS GRASS user
1

Hi,

I wonder why it's not possible to register in temporal dataset maps
from other mapsets?

Module `t.register` fails to register maps from PERMANENT mapset in my
current mapset (`landa):

t.create output=modis title="MODIS 2002" desc="Ukazkovy casoprostorovy
dataset MODIS"
g.list type=raster mapset=PERMANENT sep='newline' out=maps.txt -m
t.register input=modis file=maps.txt sep='newline'
ERROR: Unable to execute sql statement. There is no temporal database
connection defined for mapset <PERMANENT>

So I am able to register only maps from the current mapset. Why? Ma

--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

2

Hi Martin,
by default the temporal databases are mapset specific. In addition the temporal framework does not allow to register maps from other mapsets in a space time dataset. Hence space time datasets are mapset specific as well.

The reason for this are permission considerations. Several temporal commands that modify space time datasets will also modify the registered map layers. Changing the time stamps for layers will always trigger the modification of map layer metadata (time stamp files in the map layer directories). If you do not have write permissions on the mapset from which you have registered the maps, then all these commands will fail and maybe the temporal database will have issues afterwards.

However, in “THEORY” you can set the database connection for each mapset to point to a single database. Then you must set the TGIS_DISABLE_MAPSET_CHECK environment variable, so that the temporal framework does allow that map layers from different mapset can be registered in a single space time dataset. I have not tested this and there are no gunittests available yet that check for this hidden feature.

Best regards
Soeren

···

2016-04-17 12:08 GMT+02:00 Martin Landa <landa.martin@gmail.com>:

Hi,

I wonder why it’s not possible to register in temporal dataset maps
from other mapsets?

Module t.register fails to register maps from PERMANENT mapset in my
current mapset (`landa):

t.create output=modis title=“MODIS 2002” desc=“Ukazkovy casoprostorovy
dataset MODIS”
g.list type=raster mapset=PERMANENT sep=‘newline’ out=maps.txt -m
t.register input=modis file=maps.txt sep=‘newline’
ERROR: Unable to execute sql statement. There is no temporal database
connection defined for mapset

So I am able to register only maps from the current mapset. Why? Ma

–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

grass-user mailing list
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3

Hi Martin,

What if you try running t.connect -d (set from default) in PERMANENT first? The error says there’s no temporal database connection defined. Maybe that works.

Cheers,
Vero

El abr 17, 2016 7:08 AM, “Martin Landa” <landa.martin@gmail.com> escribió:

Hi,

I wonder why it’s not possible to register in temporal dataset maps
from other mapsets?

Module t.register fails to register maps from PERMANENT mapset in my
current mapset (`landa):

t.create output=modis title=“MODIS 2002” desc=“Ukazkovy casoprostorovy
dataset MODIS”
g.list type=raster mapset=PERMANENT sep=‘newline’ out=maps.txt -m
t.register input=modis file=maps.txt sep=‘newline’
ERROR: Unable to execute sql statement. There is no temporal database
connection defined for mapset

So I am able to register only maps from the current mapset. Why? Ma

–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

4

Ops, dismiss previous email… Eheh! :stuck_out_tongue:

Thanks for the explanation and hint, Sören!

El abr 17, 2016 7:32 AM, “Veronica Andreo” <veroandreo@gmail.com> escribió:

Hi Martin,

What if you try running t.connect -d (set from default) in PERMANENT first? The error says there’s no temporal database connection defined. Maybe that works.

Cheers,
Vero

El abr 17, 2016 7:08 AM, “Martin Landa” <landa.martin@gmail.com> escribió:

Hi,

I wonder why it’s not possible to register in temporal dataset maps
from other mapsets?

Module t.register fails to register maps from PERMANENT mapset in my
current mapset (`landa):

t.create output=modis title=“MODIS 2002” desc=“Ukazkovy casoprostorovy
dataset MODIS”
g.list type=raster mapset=PERMANENT sep=‘newline’ out=maps.txt -m
t.register input=modis file=maps.txt sep=‘newline’
ERROR: Unable to execute sql statement. There is no temporal database
connection defined for mapset

So I am able to register only maps from the current mapset. Why? Ma

–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

5

Hi Soren,

2016-04-17 12:32 GMT+02:00 Sören Gebbert <soerengebbert@googlemail.com>:

However, in "THEORY" you can set the database connection for each mapset to
point to a single database. Then you must set the TGIS_DISABLE_MAPSET_CHECK
environment variable, so that the temporal framework does allow that map
layers from different mapset can be registered in a single space time
dataset. I have not tested this and there are no gunittests available yet
that check for this hidden feature.

thanks for detailed explanation! Martin

--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

6

Hi Vero,
I have send my mail just a second after i recieved your mail … .

However, i would like to add that a second temporal GIS environmental variable exists, that disables the write of map layer metadata:
TGIS_DISABLE_TIMESTAMP_WRITE

Set it with:
g.gisenv set="TGIS_DISABLE_TIMESTAMP_WRITE=True

This will avoid that time stamps are written as text files in the map layer specific metadata directory by the temporal framework. The drawback is that modules written in C are not able to determine if the map layer has a timestamp using the C-API. The benefit is that map layer specific data in other mapsets are not modified if the space time dataset are modified.

Best regards
Soeren

···

2016-04-17 12:40 GMT+02:00 Veronica Andreo <veroandreo@gmail.com>:

Ops, dismiss previous email… Eheh! :stuck_out_tongue:

Thanks for the explanation and hint, Sören!

El abr 17, 2016 7:32 AM, “Veronica Andreo” <veroandreo@gmail.com> escribió:

Hi Martin,

What if you try running t.connect -d (set from default) in PERMANENT first? The error says there’s no temporal database connection defined. Maybe that works.

Cheers,
Vero

El abr 17, 2016 7:08 AM, “Martin Landa” <landa.martin@gmail.com> escribió:

Hi,

I wonder why it’s not possible to register in temporal dataset maps
from other mapsets?

Module t.register fails to register maps from PERMANENT mapset in my
current mapset (`landa):

t.create output=modis title=“MODIS 2002” desc=“Ukazkovy casoprostorovy
dataset MODIS”
g.list type=raster mapset=PERMANENT sep=‘newline’ out=maps.txt -m
t.register input=modis file=maps.txt sep=‘newline’
ERROR: Unable to execute sql statement. There is no temporal database
connection defined for mapset

So I am able to register only maps from the current mapset. Why? Ma

–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

7

2016-04-17 12:56 GMT+02:00 Sören Gebbert <soerengebbert@googlemail.com>:

Set it with:
g.gisenv set="TGIS_DISABLE_TIMESTAMP_WRITE=True

probably better would be environment variable (export) rather than
GRASS variable? Ma

--
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa

8

Hi,
I decided to use a mapset specific variable, since this will affect the temporal database of this mapset and therefore all processes related to this mapset. Hmmm … there are pros an cons for booth solutions, but i will stick with the current one. :slight_smile:

Cheers
Soeren

Am 17.04.2016 13:05 schrieb “Martin Landa” <landa.martin@gmail.com>:

2016-04-17 12:56 GMT+02:00 Sören Gebbert <soerengebbert@googlemail.com>:

Set it with:
g.gisenv set="TGIS_DISABLE_TIMESTAMP_WRITE=True

probably better would be environment variable (export) rather than
GRASS variable? Ma

–
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa