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gdal_translate and gdalwarp question

2 messages · Antonio Silva, Roger Bivand

#
Hello,

I have some doubts on the usage of some gdal tools.

After converting a hdf file to tif I want to reproject to SIRGAS2000 and
clip between lats of 22 to 29 S and lats of 40 to 50 W.

HDF file can be downloaded at
https://app.box.com/s/16cf7qv6af6gsz1v66staori2mtneu0r

Basically I'm following
https://scottishsnow.wordpress.com/2014/08/24/many-rastered-beast/

Well to convert HDF file I'm using:

gdal_translate("A20080012008031.L3m_MO_SST_4","georef.tif",sd_index=1,a_ullr=c(0,4320,8640,0),
a_srs="+proj=eqc +lat_ts=0 +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +a=6371007
+b=6371007 +units=m +no_defs")

Without a_ullr and a_srs options I was getting an error message when using
gdalwarp: "ERROR 1: Unable to compute a transformation between pixel/line
and georeferenced coordinates"

a_ullr and a_srs values I got with GDALinfo("georef.tif")

map <- raster("georef.tif")
plot(map)

My problem now is reproject to SIRGAS2000 and clip the image georef.tif:

gdalwarp("georef.tif", "georef2.tif",
s_srs="+proj=eqc +lat_ts=0 +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +a=6371007
+b=6371007 +units=m +no_defs",
t_srs="+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs")

map2 <- raster("georef2.tif")
plot(map2)

Map2 is not in SIRGAS2000 projection and clipping option
te=c(-50,-29,-40,-22) does not work.

Where is my mistake? I hope someone can tell me.

Thanks for any help.

Antonio Olinto
2 days later
#
You posted the same message to R-help at Sun Sep 20 16:52:07 CEST 2015, so 
less than two hours after this post, cross-posting is bad anyway, and for 
such a specialised question, you should never expect immediate response. 
You do not state that this concerns the gdalUtils package, nor what 
version you are using on what platform. Can you simply use the GDAl 
command line utility until you figure out what you are doing wrong?

Roger
On Sun, 20 Sep 2015, Antonio Silva wrote: