hi everyone,

     i have the set of image files in hdf format.i need to plot time series including minimum,maximum,mean and standard deviation values(geographical values) for each image in particular location(For example, Entire indian ocean).

I have daily image for three years.So i need the automatic script to get only those values to plot.

Can anyone help me as soon as possible please...

Thanks & Regards

Arthi

Arthi & Suresh,

You don't need to post the same question multiple times in multiple forums.  It was a holiday weekend here in the U.S., so this is the earliest we could have replied.

Your question is a bit too general.  Which data sets are you using?  Which tool(s) will you be using to read and manipulate the data?

You need to figure out first how you would accomplish your task for a single image:
- Read appropriate data sets and associated flags from HDF file
- Limit indices to those falling within desired geographic region
- Filter out any undesired data, according to flag values
- Calculate statistics.

Once you know how to do that, you can automate with the scripting language of your choice.
If these are unfamiliar tasks, you may want to search this forum or Google.

Arthi & Suresh,

Here is one way to compute the sorts of statistics you are looking for.
This approach assumes familiarity with the Perl scripting language and
a certain facility with image processing.  For this example, I generated
an Indian Ocean mask using GMT (and GhostScript) to make a global
ocean image.

pscoast -Rd -JQ0/43.2 -P -X0 -Y0 -S0 \
| gs -sDEVICE=pgmraw -sOutputFile=- -q -r100 -g4320x2160 - > global_ocean.pgm

I then blanked out everything but the Indian Ocean using the Gimp
to produce indian_ocean.pgm .

The attached perl script computes chlorophyll statistics for the Indian
Ocean using the Aqua-MODIS, January 2011 monthly chlorophyll SMI
product, A20110012011031.L3m_MO_CHL_chlor_a_9km .  It uses the
hdp program to read the SMI (HDF) file.

When I run the attached script, I get the following output.

min=0.0016
max=69.2769
median=0.1583
mean=0.2135
st dev=0.4194

Regards,
Norman

hi norman,

           Sorry for those repeated questions...i will remove it...

          You gave perl script....But i need IDL script....

           I have been installed seadas6.0....I want to calculate statistics in seadas...I need IDL code for calculating statistics...I searched inside seadas...But i didnt get it..

           I have files in HDF format(Calculated from MODIS L2 file) using my algorithm...I want statistics for particular location....

Thanks

Suresh M