New Zealand MODIS Band Combination

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
oceani
Posts: 49
Joined: Wed Aug 23, 2006 12:32 pm America/New_York
Answers: 0

New Zealand MODIS Band Combination

by oceani » Wed Nov 02, 2022 11:09 am America/New_York

Could someone tell me the band combination used to generate/render the 10/23/22 Aqua-MODIS image of New Zealand you have on the home page of the Ocean Color Group web site?

Thanks,

Mark

Tags:

rlossing
Posts: 2
Joined: Mon Oct 05, 2015 3:29 pm America/New_York
Answers: 0

Re: New Zealand MODIS Band Combination

by rlossing » Wed Nov 02, 2022 4:02 pm America/New_York

Hello!
I created the image with these steps and ocssw commands/programs and image manipulation processes:

1) Locate Image /Download (https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sen=amod))
***Can also look at NASA Worldview (https://worldview.earthdata.nasa.gov/) or OBPG Swath Browser(https://oceancolor.gsfc.nasa.gov/cgi/brs)
2) Process Image (i.e. if MODIS modis_GEO,l1bgen
If MODIS:
a. modis_GEO
b. modis_l1ben
c. l2gen (RGB & OC suite)
OTHERS Sensors? (will need to create a similar processing recipe...)
3) Open images with SeaDAS
a. Reproject to desired reprojection (artistic perspective) (beware images that cross the International Date Line have trouble reprojecting;need to shift longitude 180 etc... i.e. New Zealand(why this image was just a satellite sensor "raw" swath and not reprojected)
b. Create RGB (rhos 645,555,469nm) from RGB processed scene (will usually be able to pick between the "log" and "atan" rgb-iamge channel profiles (artistic choice was 'atan"; land colors seemed more vibrant...)
c. Create RRS (GREEN) 555nm (412rrs,555rrs,678 rrs) from "OC" atmospheric processed scene
b. Color correct using SeaDAS (RGB/GREEN) color bar manipulation (manually tuned the colors to get a desired "green" (very artistic interpretive step;not very scientifically done....could be improved on...) Wanted visual vibrancy/HDR impacts
c. Export both as PNG at FULL RESOLUTION

4) Import into GIMP (https://www.gimp.org/) for image "polishing/final manipulations" could use photoshop or photo editor of your preference
a. add both RGB & RRS(green) as LAYERS
b. adjust LAYERS for compositing (some "no data" areas will be transparent especially cloud tops and I just add a white background to "fill in" those; probably a better way to do this in SeaDAS using scientific flags/image expression statements etc.)
c. manually "photoshop" /color correct images further to achieve desired appearance; just experimented with image/color manipulation features (you could do a lot here...not sure the best procedure...)
d. rotate for desired aesthetic effect/crop images to make smaller sizes (1920x1080; 300x300 thumbnail etc.)
e. export images to png.

See Norman Kuring's fantastic image creation process page:(https://oceancolor.gsfc.nasa.gov/staff/norman/image_creation/)


Example Command Lines:
Initial L1A File: A2022296023000.L1A_LAC

getanc A2022296023000.L1A_LAC

modis_GEO A2022296023000.L1A_LAC

modis_L1B A2022296023000.L1A_LAC AQUA_MODIS.20221023T023000.GEO.hdf

To make "RGB image" (not atmospherically correct; gets you the LAND /clouds)
l2gen ifile=A2022296023000.L1B_LAC geofile=AQUA_MODIS.20221023T023000.GEO.hdf par=A2022296023000.L1A_LAC.anc ofile=A2022296023000.L2_250 l2prod=rhos_412,rhos_469,rhos_555,rhos_645,rhos_678 resolution=250 atmocor=off

To make "green" chlorophyll RRS image (atmospherically corrected/obpg geophysical product creation "ie. l2gen")
l2gen ifile=A2022296023000.L1B_LAC geofile=AQUA_MODIS.20221023T023000.GEO.hdf par=A2022296023000.L1A_LAC.anc ofile=A2022296023000.L2_OC_250 suite=OC resolution=250

-Robert Lossing (robert.j.lossing@nasa.gov)

rlossing
Posts: 2
Joined: Mon Oct 05, 2015 3:29 pm America/New_York
Answers: 0

Re: New Zealand MODIS Band Combination

by rlossing » Sat Nov 05, 2022 1:30 pm America/New_York

Just watched this video on the interesting Bank's Peninsula.
https://www.youtube.com/watch?v=mHjjJUDUclg

oceani
Posts: 49
Joined: Wed Aug 23, 2006 12:32 pm America/New_York
Answers: 0

Re: New Zealand MODIS Band Combination

by oceani » Tue Nov 08, 2022 3:21 pm America/New_York

Thank you very much for the detailed explanation.

-Mark

Post Reply