How to Download MODIS normalize difference vegetation index (NDVI) data from USGS?
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- Опубликовано: 12 сен 2024
- MODIS core mission, standard VI products include the normalize difference vegetation index (NDVI) and the enhanced vegetation index (EVI) to effectively characterize bio-physical/ biochemical states and processes from vegetated surfaces. There exists a com-plete, global time series record of 6 VI products from each of the Terra and Aqua MODIS sensors, at varying spatial (250m, 1km, 0.05 degree) and temporal (16-day, monthly) resolutions to meet the needs of the research and application communities.
The VI prod-ucts are validated with accuracies depicted by a pixel reliability flag and with globally
av-eraged uncertainties of 0.015 units.
The MODIS instrument is operating on both the Terra and Aqua spacecraft.
It has a viewing swath width of 2,330 km and views the entire surface of the Earth every one to two days.
Its detectors measure 36 spectral bands between 0.405 and 14.385 µm, and it acquires data at three spatial resolutions
-- 250m, 500m, and 1,000m
MODIS land products:
lpdaac.usgs.gov/
MODIS cryosphere products:
nsidc.org/daac/...
MODIS ocean color and sea surface temperature products:
oceancolor.gsfc...
Thank you Ravi for Your kind help to make intro video...
Thank you all..
Great video. You know ndvi value is between -1 to +1 but in this video the value is toommuch. How do you do to convert this value. Thak you
you should reiterate your data
@@Geoinfonepal how can reiterate our modis data to make value between -1 to +1 ndvi . plz help me
@@developerakram9750 you should multiply the reflectance value with your current NDVI value.note that reflectance value is given in metadata when you download the NDVI modis product
@@Geoinfonepal Could you please help multiply the reflectance value
@@mohammedkareem6476 Hi, I'm new to remote sensing. However, I believe you can get an idea of the scale factors from this document. salsa.umd.edu/files/MOD09_UserGuide_v1.4.pdf. You can download the user guide and identify values based on your requirements. if this is wrong please correct me.
Which extension is good for ArcMap?
you mean version of arcgis or what?
@@Geoinfonepal Pradeep Gyawali no, i mean when you save the files from Earth Explorer you can save them with different extensions, .hdf for example. And which one is compatible to open the image in arcgis? But i saw that .hdf can be opened in argis. Thank you for the video!
@@Geoinfonepal are this images radiometric corrected? Or any other corrections. I am new at this, i am studying hidrology and i want to study drought with this kind of images.
Okay thank you for your question...first of all..in case of modis ..your image is in .hdf format and you need to reproject it into wgs using modis MRT tool at that time your hdf format can also be changed into .tif format...and your yeah in case of modis product like modis ndvi/modis lst, the data is obtained from usgs is radiometrically as well as geometrically corrected but in case of images not product like landsat image we need to apply geometric and radiometric correction ...or you can look the image meta data to find the info about correction whether it is corrected or not corrected.
@@Geoinfonepal thank you for your answer! It really helps a lot!
I still can't download it even it was already login. It keep repeating the login page.
Have you conformed from the mail which you used in usgs account ?
haha