MODIS SIN Grid data(MOD16A2) visualization.

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
kmmrao
Posts: 13
Joined: Wed Dec 29, 2021 1:53 am America/New_York
Answers: 0

MODIS SIN Grid data(MOD16A2) visualization.

by kmmrao » Thu Jul 13, 2023 1:52 pm America/New_York

I am trying to extract MODIS ET SIN Grid data(MOD16A2) for some time period. I am able to extract the data rasters but trying to create one-dimensional longitude and latitude arrays from longitude-minimum/maximum and latitude-minimum/maximum. When I am trying to do this the plot is shifting to the left of the plot. The Python code is attached.
Attachments
EarthDataForum - Jupyter Notebook_compressed.pdf
Python code
(240.67 KiB) Downloaded 48 times

Tags:

LP DAAC - dgolon
User Services
User Services
Posts: 241
Joined: Mon Sep 30, 2019 10:00 am America/New_York
Answers: 0
Has thanked: 12 times
Been thanked: 2 times
Contact:

Re: MODIS SIN Grid data(MOD16A2) visualization.

by LP DAAC - dgolon » Fri Jul 14, 2023 10:18 am America/New_York

Hi @kmmrao We'll take a look at your code and get back to you. Thanks - Danielle
Subscribe to the LP DAAC listserv by sending a blank email to lpdaac-join@lists.nasa.gov.

Sign up for the Landsat listserv to receive the most up to date information about Landsat data: https://public.govdelivery.com/accounts/USDOIGS/subscriber/new#tab1.

ogsahin
Posts: 4
Joined: Sun Jul 16, 2023 10:26 pm America/New_York
Answers: 0
Been thanked: 1 time

Re: MODIS SIN Grid data(MOD16A2) visualization.

by ogsahin » Sun Jul 16, 2023 10:47 pm America/New_York

hdf and netcdf files are stored latitude maximum to minimum (left to right). I think the problem is line 19 in your code. Latitude values need to decrease, not increase, in numpy array.

kmmrao
Posts: 13
Joined: Wed Dec 29, 2021 1:53 am America/New_York
Answers: 0

Re: MODIS SIN Grid data(MOD16A2) visualization.

by kmmrao » Mon Jul 17, 2023 1:27 pm America/New_York

Ok, understood, but the map shifting to left in the high latitudes. How to fix it?

ogsahin
Posts: 4
Joined: Sun Jul 16, 2023 10:26 pm America/New_York
Answers: 0
Been thanked: 1 time

Re: MODIS SIN Grid data(MOD16A2) visualization.

by ogsahin » Tue Jul 18, 2023 5:01 am America/New_York

lats= np.linspace(lat.min(),lat.max(),2400) this one is wrong. It should be

lats= np.linspace(lat.max(),lat.min(),2400)

kmmrao
Posts: 13
Joined: Wed Dec 29, 2021 1:53 am America/New_York
Answers: 0

Re: MODIS SIN Grid data(MOD16A2) visualization.

by kmmrao » Tue Jul 18, 2023 9:21 am America/New_York

Hi,
Thanks for your response,
Let me explain, if you are into Python, no matter what
lats= np.linspace(lat.max(),lat.min(),2400) (or)
lats= np.linspace(lat.max(),lat.min(),2400)

My point is simple and straight. When I change the coordinate system from
Sinusoidal to Mercator projection. Still, the map is bending towards the left with an increase in latitude from the equator.
Should I need to use any offset to lats= np.linspace(lat.max(),lat.min(),2400) ??
or to lons ?

ogsahin
Posts: 4
Joined: Sun Jul 16, 2023 10:26 pm America/New_York
Answers: 0
Been thanked: 1 time

Re: MODIS SIN Grid data(MOD16A2) visualization.

by ogsahin » Tue Jul 18, 2023 11:28 pm America/New_York

1) You used (lon, lat) and (lons, lats) coordinates, both of them wgs84, and asked why this map is shifting. It is impossible to understand "simple and straight" point when we follow jupyter notebook you shared.

2) Of course, maps will shift if you are projecting them and there is no solution. How do you expect to get the exact map representation (visualization) after projecting it?

3) If you want to extract ET products for a specific location, just use the AρρEEARS software. Otherwise, you must handle and merge more than one "hdf" file.

LP DAAC - afriesz
Subject Matter Expert
Subject Matter Expert
Posts: 54
Joined: Tue Nov 12, 2019 4:02 pm America/New_York
Answers: 1
Been thanked: 1 time

Re: MODIS SIN Grid data(MOD16A2) visualization.

by LP DAAC - afriesz » Tue Aug 15, 2023 10:02 am America/New_York

@kmmrao ,

Have you been able to explore NASA's AppEEARS (https://appeears.earthdatacloud.nasa.gov/) as @ogsahin mentioned? I think it would help. Another option outside of Python is to use the GDAL Warp (https://gdal.org/programs/gdalwarp.html) utility.

Post Reply