I have downloaded GIMMS NDVI3g data from http://ecocast.arc.nasa.gov/data/pub/gimms/3g/
I now need to open the files in arcgis. I have the follwing GRID PARAMETERS:
grid-name: Geographic Lat/Lon
pixel-size: 1/12=0.0833 degrees
size-x: 4320
size-y: 2160
upper-left-lat: 90.0-1/24
upper-left-lon: -180.0+1/24
lower-right-lat: -90.0+1/24
lower-right-lon: 180.0-1/24
I want to ask if someone has worked with these files yet since the release is recent and how you opened the files? And if a header file is needed how do I create multiple header files in one step? (there are 700 files covering 3 decades)…
Best regards,
Johan
Best Answer
I know you explicitely asked for an ArcGIS solution. However, I just stumbled accross the same problem when trying to import GIMMS NDVI 3G data into R. So in case anybody needs this in future times, here is the solution I came up with.
Basically, my approach is built on
read.ENVI
from thecaTools
package. However, to successfully import the binary data into R, you need to set up a companion header file as mentioned above. Following the documentation provided by?read.ENVI
, it looks quite different from the one ArcGIS can deal with:You need to save these lines to a separate *.hdr file, which you can supply to
read.ENVI
later on. Of course, if you are dealing with multiple GIMMS binary files, you can use the same header file again and again since all settings remain unchanged. Like that, it is quite simple to import the data into R:read.ENVI
returns a 'matrix' by default, which you can then easily transpose calling thet
function and, finally, insert the values into a 'RasterLayer' object usingraster(...)
.Update:
You may now also have a look at the R gimms package which renders unnecessary the use of
read.ENVI
. To create an ordinary GeoTIFF from the downloaded GIMMS binary data and make the file available in R as 'Raster*' object, simply runrasterizeGimms
. A comprehensive introduction to the package is available from GitBook.