Re: [gdal-dev] gdalwarp over tiles in Plate carée

[Nikolaos Hatzopoulos]

I haven't worked with MERIS on NDVI data but I know about MODIS:

so let's say we have four MODIS files lvl3 data:
MOD13Q1.A2010113.h08v04.005.2010133194933.hdf
MOD13Q1.A2010113.h08v05.005.2010134041223.hdf
MOD13Q1.A2010113.h09v04.005.2010135200404.hdf
MOD13Q1.A2010113.h09v05.005.2010133080730.hdf

if you go to the map:
https://lpdaac.usgs.gov/lpdaac/products/modis_overview

you are going to see that these tiles represent the west coast

what I do is extract the data from hdf to geotiff

if you do gdalinfo MOD13Q1.A2010113.h08v04.005.2010133194933.hdf

you are going to have:
...
 SUBDATASET_2_NAME=HDF4_EOS:EOS_GRID:"MOD13Q1.A2010113.h08v04.005.2010133194933.hdf":MODIS_Grid_16DAY_250m_500m_VI:250m
16 days EVI
  SUBDATASET_2_DESC=[4800x4800] 250m 16 days EVI
MODIS_Grid_16DAY_250m_500m_VI (16-bit integer)

SUBDATASET_3_NAME=HDF4_EOS:EOS_GRID:"MOD13Q1.A2010113.h08v04.005.2010133194933.hdf":MODIS_Grid_16DAY_250m_500m_VI:250m
16 days VI Quality
  SUBDATASET_3_DESC=[4800x4800] 250m 16 days VI Quality
MODIS_Grid_16DAY_250m_500m_VI (16-bit unsigned integer)

SUBDATASET_4_NAME=HDF4_EOS:EOS_GRID:"MOD13Q1.A2010113.h08v04.005.2010133194933.hdf":MODIS_Grid_16DAY_250m_500m_VI:250m
16 days red reflectance
  SUBDATASET_4_DESC=[4800x4800] 250m 16 days red reflectance
MODIS_Grid_16DAY_250m_500m_VI (16-bit integer)

...

you do:

gdal_translate
'HDF4_EOS:EOS_GRID:"MOD13Q1.A2010113.h08v04.005.2010133194933.hdf":MODIS_Grid_16DAY_250m_500m_VI:250m
16 days NDVI' image1.tif
0...10...20...30...40...50...60...70...80...90...100 - done.

so you will have your first tif

you do the same for the others files

and you will have:
image1.tif
image2.tif
image3.tif
image4.tif

we are going to make a virtual mosaic using the vrt format:

gdalbuildvrt mosaic.vrt *.tif

if you open in a text editor the mosaic .vrt you are going to see the
details

now we are going to convert the mosaic to WGS84 projection
gdalwarp -t_srs WGS84 mosaic.vrt final.tif

my final.tif does not have any lines

On Thu, Jul 7, 2011 at 5:02 PM, katrin eggert <katrineggert1980 at gmail.com>wrote:

> Greetings
> I'm using gdalwarp to reproject a few tiles from platecarré to UTM WGS84
> (for a specific zone). Originally they are tiles so they don't have any
> "blank" space between them but when I reproject to UTM I get a few areas in
> the borders of the image. What can I do to still have a perfect match
> between tiles?
> Thanks
> Kat
>
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