Search found 146 matches

by LP DAAC - lien
Mon Mar 04, 2024 3:56 pm America/New_York
Forum: Questions/Comments
Question: How should pixel values greater than 10,000 or less than 0 in MOD09GA data be handled?
Replies: 4

Re: How should pixel values greater than 10,000 or less than 0 in MOD09GA data be handled?

Hi Zhou,
Yes, that is what I would suggest, treating them like fill value. Certainly don't use those particular pixels for scientific research.
Thanks,
Brett
by LP DAAC - lien
Mon Mar 04, 2024 9:40 am America/New_York
Forum: Questions/Comments
Question: How should pixel values greater than 10,000 or less than 0 in MOD09GA data be handled?
Replies: 4

Re: How should pixel values greater than 10,000 or less than 0 in MOD09GA data be handled?

Hi, Yes, this is somewhat common especially in daily data, practically every tile has some of these outliers. They should not be used, they are erroneous data. Please see the statement below which gives more specifics on why this is the case: The "anomalies" that you've identified, e.g. ne...
by LP DAAC - lien
Fri Mar 01, 2024 9:37 am America/New_York
Forum: Questions/Comments
Question: MODIS MOD09A1 v6.1 invalid QC codes?
Replies: 4

Re: MODIS MOD09A1 v6.1 invalid QC codes?

Thanks for the tile info Hawthorne. I have found those values in many random files since you brought that to our attention. We have contacted the folks at LDOPE who help develop the products and also specialize in the QC. As soon as we hear back from them I will let you know. Thanks for your patienc...
by LP DAAC - lien
Wed Feb 28, 2024 10:18 am America/New_York
Forum: Questions/Comments
Question: MODIS MOD09A1 v6.1 invalid QC codes?
Replies: 4

Re: MODIS MOD09A1 v6.1 invalid QC codes?

Hello,
Thanks for bringing this to our attention, do you have a specific Granule ID, we would like to show this to the MODIS Science Team and make them aware of this. Our first thought is maybe the bits got inverted, but either way something is amiss.
Thanks,
Brett
by LP DAAC - lien
Tue Feb 27, 2024 12:25 pm America/New_York
Forum: Questions/Comments
Question: MCD19A2 incorrect tile size
Replies: 2

Re: MCD19A2 incorrect tile size

Hi, Sorry for the misinformation with this. The more precise size of the what is referred to as 500 meter MODIS pixel is actually 463.3127 meters. Each MODIS 500 meter product will have 2400 x 2400 pixels. The native format for the gridded MODIS products are Sinusoidal and this makes the MODIS image...
by LP DAAC - lien
Tue Feb 27, 2024 11:57 am America/New_York
Forum: Questions/Comments
Question: MCD19A2 AOD data preprocessing
Replies: 4

Re: MCD19A2 AOD data preprocessing

Hello, I am really not sure on how you get get a csv file for AOD. Because of the multiple dimensions of the file, this product is not available in our AppEEARS tool. I am not sure if ArcMap can do that or not. You may have to check with the software documentation for many of these questions: https:...
by LP DAAC - lien
Tue Feb 27, 2024 9:10 am America/New_York
Forum: Questions/Comments
Question: Slow Download of HDF files using urllib
Replies: 1

Re: Slow Download of HDF files using urllib

Good Morning,
Could you send us you script and we can take a look to see what may be going on. I can't think of any changes on e4ftl01.cr.usgs.gov that may have caused this.
Thanks,
Brett
by LP DAAC - lien
Wed Feb 21, 2024 9:27 am America/New_York
Forum: Questions/Comments
Question: MODIS 8 Day or 16 Day Composite
Replies: 2

Re: MODIS 8 Day or 16 Day Composite

Hello, Yes, the day mentioned is the first day of the composite period, so in your example the period would be from January 1 through the 8th of January. This is true with all MODIS/VIIRS products, with one exception. That exception is the MCD43 BRDF/Albedo products. Those are 16 day products, but t...
by LP DAAC - lien
Tue Feb 20, 2024 9:29 am America/New_York
Forum: Questions/Comments
Question: Downloading MOD13A1 and MYD13A1 files - methods?
Replies: 4

Re: Downloading MOD13A1 and MYD13A1 files - methods?

Hello,
Could you attach your python code and we can take a look, Also, could you attach the text file then we can see where you compile it from. If you would like you could send it to the LPDAAC email: lpdaac@usgs.gov
Thanks,
Brett
by LP DAAC - lien
Fri Feb 16, 2024 10:37 am America/New_York
Forum: Questions/Comments
Question: MODIS MOD09A1 Product negative reflectances
Replies: 1

Re: MODIS MOD09A1 Product negative reflectances

Hi Niklas, Sorry, but I don't think there is much that can be done about that, the MOD09 products are not recommended for water pixels. The "anomalies" that you've identified, e.g. negative reflectance values, are known issues in MODIS along with many other Surface Reflectance products suc...