Incorrect shape of OB tiles/areas?

[Marina Rejkuba]

Seems that the union of tiles produces some (very few) unusual looking shapes - not sure whether this comes from the JSON input files or from the way that SVMT combines them.
Examples:

1) VVV - select all OBs.
look at OBs distributed between -60>l>-65, 2.5>b>-2.5

2) VVV - select all OBs
look at OB ID 430037 that is located around RA/DEC = 18h03m18.8sec/-33deg08'08.8"

[Fabien Chéreau (xalioth)]

This probably doesn't come from the client, in the GUI, this OB 430037 indicates a position angle close to zero, which corresponds to the way it is displayed. Could you inspect the OB manually in the data base to see whether it contains erroneous rotation information?

[Marina Rejkuba (mrejkuba)]

Hi Fabien,

When I looked at the SVMT with Diego and you, you explained that this
tile has "funny" shape due to the way that the tile grouping is done.
There are several OBs with different orientation that overlap and the
grouping made a shape that is not expected.

this is not critical problem, but it would be nice (low priority!) to
combine in groups the tiles that have the same orientation. Those that
have different orientation should be overplotted with full
contours/lines without grouping them with other tiles with different
oritentation. I hope I am explaining myself. If not, please tell me and
I can probably easier explain it by making a small drawing...

cheers,
marina

On 08/12/2010 11:58 AM, Fabien Chéreau wrote:
> This probably doesn't come from the client, in the GUI, this OB 430037
> indicates a position angle close to zero, which corresponds to the way
> it is displayed. Could you inspect the OB manually in the data base to
> see whether it contains erroneous rotation information?
>
> ** Changed in: svmt
> Status: New => Incomplete
>

[Diego (diego-marcos)]

The angle stored in the database for the OB with ID 430037 is 0.0245000000

There are other OB's with rotation close to zero.

e.g:

OB 432052 - 0.0648000000

OB 432595 - 0.0789000000

How can I know whether those are erroneous values?

[Marina Rejkuba (mrejkuba)]

On 08/12/2010 12:19 PM, Diego wrote:
> The angle stored in the database for the OB with ID 430037 is
> 0.0245000000
>
> There are other OB's with rotation close to zero.
>
> e.g:
>
> OB 432052 - 0.0648000000
>
> OB 432595 - 0.0789000000
>
> How can I know whether those are erroneous values?
>

Hi Diego,

The rotator position can be also different from zero... this is not
erroneous. Depends how the OB was constructed.

marina