Search found 141 matches

by OB WebDev - norman
Thu Apr 02, 2020 2:02 pm America/New_York
Forum: Home
Question: Featured images
Replies: 13

Featured images

Oh, with regards to your comment about applying a palette under gimp: I do notuse the chlorophyll images in that way i.e. as indexed color look-up tables.  I blendthe gray-scale chlorophyll images with the other layers using blending modes suchas "soft light".  That particular bl...
by OB WebDev - norman
Thu Apr 02, 2020 1:55 pm America/New_York
Forum: Home
Question: Featured images
Replies: 13

Featured images

Hi Fabrizio,We have the same issues accessing our work place at Goddard Space Flight Center inMaryland.  Yes, these are challenging times.There is still something wrong with the files you are generating.  They should nothave those holes in the grid.  I notice that you have many key li...
by OB WebDev - norman
Thu Apr 02, 2020 11:25 am America/New_York
Forum: Home
Question: Surface and subsurface blooms in MODIS data
Replies: 2

Surface and subsurface blooms in MODIS data

Perhaps in the future we may be able to vertically resolve phytoplankton using
LIDAR from space.

See advance number 1 under the Satellite section of this paper.
https://doi.org/10.3389/fmars.2019.00251

Norman
by OB WebDev - norman
Tue Mar 31, 2020 10:11 am America/New_York
Forum: Home
Question: Featured images
Replies: 13

Featured images

Hi Fabrizio,I looked at a couple of your images, and the moiré patterns indicate that thechosen search radius passed to nearneighbor is too small for the spacing ofthe projected input data.  A couple of possibilities spring to mind.(a) I am not familiar with R.  Are you sure that your Rscr...
by OB WebDev - norman
Mon Mar 30, 2020 10:03 am America/New_York
Forum: Home
Question: Geolocation issue with l2gen
Replies: 4

Geolocation issue with l2gen

Hi Armin,

I have generally found the geolocation provided by the orthorectified
Landsat 8 data from USGS to be pretty good.  I would suspect the
land mask you are using is the problem.  The l2gen software does not
change the original projection supplied by USGS.

Norman
by OB WebDev - norman
Fri Mar 27, 2020 12:49 pm America/New_York
Forum: Home
Question: Geolocation issue with l2gen
Replies: 4

Geolocation issue with l2gen

Hi Armin,For Landsat, I would suggest that you not use the land-mask that comes along withl2gen; it is just not of high enough resolution or accuracy.  When I need to discriminatebetween land and water in Landsat 8 data, I like to compute rhos_865 from Band 5and choose a threshold reflectance t...
by OB WebDev - norman
Tue Mar 24, 2020 1:45 pm America/New_York
Forum: Home
Question: Size of 1 day level 2 data on global scale
Replies: 3

Size of 1 day level 2 data on global scale

Hi Eligio,Compression ratio will vary depending on the contents of the scene.L2 scenes that have large areas masked out (e.g. for land) willcompress much smaller than those with a more complete andvarying feature set.If I were you, I would set up a processing flow that downloadsscenes serially and d...
by OB WebDev - norman
Thu Mar 19, 2020 8:57 am America/New_York
Forum: Home
Question: Size of 1 day level 2 data on global scale
Replies: 3

Size of 1 day level 2 data on global scale

Hi Eligio,You can get daily level-2 volumes by adding up the file sizes in bytesfrom pages like this representative Aqua/MODIS page from yesterday.https://oceandata.sci.gsfc.nasa.gov. (/MODIS-Aqua/L2/2020/078/). If you are only interested in coastal regions, you will obviously haveless data to proce...
by OB WebDev - norman
Tue Mar 03, 2020 10:13 am America/New_York
Forum: Home
Question: Data Quality and need of Regional Algorithm
Replies: 6

Data Quality and need of Regional Algorithm

In addition to heavy suspended sediment load in the Bay of Bengal,the region also suffers from perennially bad air quality.  This negativelyaffects the accuracy of the MODIS atmospheric correction.I am afraid your reviewers are correct.  Ocean color remote sensingis difficult even over cle...
by OB WebDev - norman
Tue Jan 14, 2020 1:38 pm America/New_York
Forum: Home
Question: modis-aqua adg_443_giop
Replies: 6

modis-aqua adg_443_giop

Hi Robert,I've been having some hallway conversations with folks whoknow a lot more about how our sausage is made than I do.The general thinking is that MODIS instrument calibrationis a never-ending process as the aging spacecraft is exposedto the ever changing space environment.  As one ge...