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cannot draw green box with VIIRS file
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Author:  hproe [ 06 Oct 2014, 09:59 ]
Post subject:  cannot draw green box with VIIRS file

Hi -

I have a VIIRS granule from CLASS in which I cannot draw the green box to select the ROI. Other granules behave normally, as does the same granule downloaded from PEATE. I get this problem under both Windows 7 and 8.1 with recent beta2 versions. I have uploaded the GMTCO_npp_d20140929_t1235172* and SVM15_npp_d20140929_t1235172* files to /pub/incoming.


Author:  bobc [ 07 Oct 2014, 14:07 ]
Post subject:  Re: cannot draw green box with VIIRS file

Hi HP -

Thanks for reporting this and for also posting your data. Using your CLASS granule, I am replicating your issue. One thing that I noticed about the granule is that if I display the full thing without any subsetting, the very upper left corner of the granule crosses over the dateline. There are some known problems with subsetting across the dateline, which is inquiry 1333. In most cases that I've seen, when granules cross the dateline, I can still draw a bounding box on the eastern side of the dateline, but that's not the case here. I'm wondering if this is because such a small portion of the granule crosses the dateline.

You mentioned that you didn't see this problem with the granule loaded from PEATE. I downloaded the data from PEATE and I was able to replicate the problem. Here's the granules I downloaded:
... along with the GMTCO geolocation files for each SVM15 data granule.

These four granules from PEATE (when aggregated together) match up with the data you sent from CLASS and I can't subset here, either. The problem is with the *_t1235172 granule, which is the one that barely crosses the dateline. Interestingly, I ordered the granule from one timestep earlier (which crosses the dateline some more):
... and subsetting works as I would expect it to when the data crosses the dateline (it's much easier to subset a region).

I'll add more details of this to Inquiry 1333, and I'll meet with our NPP programmer to make him aware of this (new) dateline-related subsetting issue.

Thanks again for making us aware of this issue -
Bob Carp

Author:  hproe [ 07 Oct 2014, 16:25 ]
Post subject:  Re: cannot draw green box with VIIRS file

You are right Bob, the dateline is the issue. With PEATE I have been successful because I only needed one granule at t1235426 that happens to be east of the dateline. Actually, the CLASS granule can be subsetted in a limited way: start with the box somewhere off the Canadian coest and a box will grow east of where you pointed first, e.g. with some trial-and-error you may succeed to cut out Kodiak Island.


Author:  bobc [ 09 Oct 2014, 19:57 ]
Post subject:  Re: cannot draw green box with VIIRS file

Hi HP -

Thanks for the followup about your peate data as well as being able to partially subset a region in the CLASS granule. I saw similar results with subsetting the CLASS data... sometimes I could subset a small part of the granule fine, and sometimes a box would be drawn, but it wouldn't be drawn where I was trying to draw it. Either way, it didn't seem to be very reliable. I added this information to Inquiry 1333.

Thanks again -

Author:  hproe [ 22 Feb 2017, 17:16 ]
Post subject:  Re: cannot draw green box with VIIRS file

Hi -

I am just curious about the status of inquiry 1333, obviously an oldie. Its priority is labelled as 'high', it appears to be left hanging somewhere in the queue. Could it be that my recent bug report 'VIIRS SDR navigation not working over (north) pole' is related to dateline issue?


Author:  bobc [ 24 Feb 2017, 14:48 ]
Post subject:  Re: cannot draw green box with VIIRS file

Hi HP -

I checked with a couple programmers and no one has had a chance to look much into this inquiry yet. It is considered to be a high priority item because it is one of the few problems/limitations with the Suomi NPP chooser that is keeping it from moving out of the Under Development tree in the Data Explorer. There's a definite possibility that your north pole issue is related to this inquiry, but it might just be showing the problem in a different way (with swathToGrid()).

Inquiry 1333 notes problems subsetting in the Region tab of the Field Selector without using the swathToGrid() formula. For example, you might only be able to draw a bounding box on one side of the dateline:
File comment: Dateline subset box NPP
datelineNppRegionSubset.png [ 29.33 KiB | Viewed 234 times ]

In the image above, I can only draw a box on the right side of the dateline. If I try expanding the green bounding box further to the left the box disappears and there's an error at Create Display. I'm not seeing this exact problem with your north pole data, but again this could be the same problem showing itself in a different way.

I just cross referenced Inquiry 1333 with the new inquiry I wrote for your other recent forum post (Inquiry 2494).

Thanks -

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