Longitude in Feature Classification Flag data block

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fernanda.cabello
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Longitude in Feature Classification Flag data block

by fernanda.cabello » Wed Mar 22, 2023 3:10 pm America/New_York

I download the Vertical Feature Mask Product (VFM) from CALIOP, at the spatial coordinates -61.4660W, -63.452S, -56.4660W, -60. 952S to be able to cover the red point as shown in the figure, the closest point is -62.2039 S -58.0951 W, when classifying the Layout of the Feature Classification Flag data block, in the horizontal dimension, the 5 km for that file starts from -58.951W towards the right of the map? or the -58.951W is in the center of those 5 km? Thank you very much in advance,
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ASDC - rkey
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Re: Longitude in Feature Classification Flag data block

by ASDC - rkey » Mon Mar 27, 2023 4:08 pm America/New_York

Greetings Fernanda,

Thank you for asking your questions on the forum. We have contacted the data provider for assistance regarding your CALIPSO questions and expect to post a response soon.

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Re: Longitude in Feature Classification Flag data block

by ASDC - rkey » Wed Mar 29, 2023 8:05 am America/New_York

Schematic below is from VFM data description document: https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/data_summaries/vfm/index_v420.php#feature_classification_flags

I don’t know the size of your subset file is, but for a given file the Feature_Classification_Flag is of size N x 5515 while Longitude is of size N. Each N block of VFM data is represented below. For your specific question, the -58.0951W represents the center point of the 5km horizontal chunk of the block. There are 15 333m single shot profiles (15 x 333m = ~5km) below 8.2km, so the center point corresponds to the 7th single shot profile.
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