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I am trying to merge and reproject MODIS 250m NDVI product (https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table/myd13a3_v006) to EASE2.0 grid. I am interested in projecting these to 9km EASE2.0 grid (defined by NSIDC for SMAP mission), but I have tried with the 36km EASE2.0 grid as well and I have the same problem as below.

I first use pymodis library to merge all the tiles from each month of MODIS data and generate a mosaic version of the data. Then I use gdalwarp with the following command to project to EASE2.0 grid:

gdalwarp -overwrite -tr 9008.055210146 9008.055210146 -t_srs '+proj=cea +lat_0=0 +lon_0=0 +lat_ts=30 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m' -r average mosaic_input.tif output.tif

The issue is that the output.tif file does not have the same lat/lon in each pixel as the EASE2.0 9km grid. The number of columns in the longitudinal direction are the same, but the corresponding longitudes are not the same. These are the longitudes of the center of pixels from columns 1 to 10:

179.895906749369    179.989345967666    -179.917214814038   -179.823775595741   -179.730336377444   -179.636897159148   -179.543457940851   -179.450018722554   -179.356579504258   -179.263140285961

The same issue happens with latitudes. The upper latitude in the output.tif file is 86.9278324335268 (center of the pixel), while the 9km EASE2.0 grid has an upper latitude of 84.6564407348633.

I should add that I am sure the merging with pymodis is working fine because when I use the mosaic file with gdalwarp and reproject it to EPSG 4326 (rectangular lat/lon grid) the output file has the the correct lat lon info.

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