maybe a loop will help.

set "var=1 2 3 4"

for %%a in (%var%) do (

set /a DAY=%DAY% + %%a

)

I don't test this code, but it should be helpful.

Well, if I do so that means I need to calculate the difference beween days(n)-days(n-1)? 

n is the month...right?

Hello Yifan

You can try with the script developed by Babak Naimi, available in http://r-gis.net/?q=ModisDownload

The ModisDownload function allows to mosaic all images from the same date. In addition, you can also reproject the images at the same time.

http://r-gis.net/?q=ModisDownload

MODIS r package (https://r-forge.r-project.org/R/?group_id=1252) gives you the possibility to use MRT and path mosaic images much easier than using MRT.

Example: runGdal( job="LSTaustria", product="MOD13A1", extent="Austria", begin="2010001", end="2010005",

SDSstring="101", outProj="+proj=utm +zone=34 +ellps=WGS84 +datum=WGS84 +units=m +no_defs")

You can do the following:

An alternative is to use MRTWeb (if you don't have to do the job very often) https://lpdaac.usgs.gov/data_access/mrtweb