Where do I get the NDVI data from?
(1) Download MODIS tiles containing the NDVI information for the appropriate geographic area and point in time. First, go to the website for the USGS EarthExplorer. If you don’t already have an account, you can easily create one here.
How to extract NDVI values from Windows NT +?
Download the Windows NT +32-bit version of the tool. Next, create a folder in your C Drive and call it MRT. Extract the content of the download into the MRT folder. When extracted, click on the mrt_install.bat file. On the screen that pops up, press any key to continue. You may get a warning that this directory already exists.
How can I download NDVI data from EarthExplorer?
Approach: I’ll be using a combination of EarthExplorer online tools and software and R v. 3.4.0. (1) Download MODIS tiles containing the NDVI information for the appropriate geographic area and point in time. First, go to the website for the USGS EarthExplorer. If you don’t already have an account, you can easily create one here.
How often is NDVI data collected by MODIS?
NDVI is collected by the MODIS satellite platform at 16-day intervals. The issues are (1) downloading the appropriate data, (2) reprojecting this data – not as simple a task as it sounds, and (3) extracting the NDVI values at coordinate points.
Is there a way to read HDF files into R?
The data files come in .hdf format and there doesn’t seem to be an easy way to read them into R. Compared to other topics there isn’t a lot of advice out there and most of it is several years old. Some of it also advises using additional programmes but I want to stick with just using R.
How to calculate the NDVI in raster data?
To calculate NDVI, you use the following formula where NIR is near infrared light and red represents red light. For your raster data, you will take the reflectance value in the red and near infrared bands to calculate the index.