Troubleshooting downloading MODIS NDVI Data in R

Question

I am trying to download MODIS Data from 2000-2018, however I am encountering some difficulties.

Here is my script

         MODISoptions(localArcPath = "/Volumes/myserver/MODIS/data", 
         outDirPath = "/Volumes/myserver/MODIS/data/proc_data")
         runGdal("MOD13A2", collection = "006", # see getCollection("MOD13Q1", forceCheck = TRUE)
         tileH = 8, tileV = 7, # MODIS tile id
         begin = "2000.02.18", end = "2018.03.31", # time period
         SDSstring = "110000000000") # SDS layers to extract (here: NDVI, EVI)

I am trying to do multiple dates from H: 6-8, and V: 7-9. However, when I run it, the program downloads several tiles then encounters this error:

   "Username/Password Authentication Failed.
   Remote connection failed! Re-try: 1 Getting file from: LAADS 
   trying URL 'ftp://ladsweb.nascom.nasa.gov/allData/6/MOD13A2/2000/353/MOD13A2.A2000353.h08v07.006.2017285143550.hdf' 
   Content type 'unknown' length 7085835 bytes (6.8 MB)
   Downloaded after: 2 re-tries 
   Error in load(fls_col) : empty (zero-byte) input file"

How do I get around this?

I believe it to be a missing tile, and the code terminating instead of skipping it, and going to the next one.

Answer 1

LAADS FTP is deprecated and its data moved to HTTPS. Use MODIS_1.1.3 (or higher) which covers this important migration. With this package version, your code runs smoothly on my machine.

library(MODIS)

tfs = runGdal("MOD13A2", collection = "006", 
              tileH = 8, tileV = 7, 
              begin = "2000.02.18", end = "2000.03.10", 
              SDSstring = "110000000000") # extract NDVI and EVI
tfs
# $`MOD13A2.006`
# $`MOD13A2.006`$`2000-02-18`
# [1] "../MODIS_ARC/PROCES~1/MOD13A2.006_20180912132721/MOD13A2.A2000049.1_km_16_days_NDVI.tif"
# [2] "../MODIS_ARC/PROCES~1/MOD13A2.006_20180912132721/MOD13A2.A2000049.1_km_16_days_EVI.tif" 
# 
# $`MOD13A2.006`$`2000-03-05`
# [1] "../MODIS_ARC/PROCES~1/MOD13A2.006_20180912132721/MOD13A2.A2000065.1_km_16_days_NDVI.tif"
# [2] "../MODIS_ARC/PROCES~1/MOD13A2.006_20180912132721/MOD13A2.A2000065.1_km_16_days_EVI.tif"

For further details and download alternatives (ie. get data from LP DAAC using Earthdata login credentials), please check out my answers to the following SO questions:

• Download MODIS/MCD19A2 AOD product with R
• and MODIS R Connection error.