No, what I was doing was different:
I was setting the project to 18S (not 18N) with OTF reprojection, the raster to
18N
and the vector layers got reprojected to 18S but the raster
was not displayed.
I was expecting the raster to be located in the S hemisphere because
the coordinates are negative. In TNTmips, as the coordinates are negative, even
if the raster CRS is set
to 18N, the raster is displayed in the S hemisphere. Not sure if this
is what qgis should do, though, as we are dealing with wrongly annotated
raster layers: in UTM, S is S, not negative N.
On the other hand, I assumed that if you set the project to 18N, then the vector
layers would projected to the N hemisphere.
But have tried defining the project as 18N as you say, used Coordinate capture
to check lon,lat, and actually get correct lon,lat coordinates (in the S
hemisphere). The vector layers are reprojected to
18, no matter the S or N, the original latitude correctly defines the
hemisphere.
So it works "your way", thanks!
Agus
Micha Silver wrote:
Hi Agus:
I am actually able to do just that. I also am using some Landsat
GEOCover images from below the equator, projected, as you say in UTM 39_N_.
I load the raster, set the project CRS to that (UTM Northern)
projection, and enable OTF projection. Then I can overlay vector layers,
which are WGS84 Lon-Lat., and they are correctly located.
It's usually not very helpful to say "works for me" but...
Anyway, HTH,
Micha
Agustin Lobo wrote:
The global set of Landsat images on GEOCOVER
https://zulu.ssc.nasa.gov/mrsid/mrsid.pl
is on UTM/WGS projection
but with the Southern hemisphere tiles as UTM zones in the N with
negative coordinates. For example, a tile that should be at 18S is
actually 18N with negative coordinates
("Non-standard UTM definition: For the southern hemisphere, the
GeoTiff files
contain positive zone numbers with negative northing coordinates")
https://zulu.ssc.nasa.gov/mrsid/docs/GeoCover_circa_2000_Product_Description.pdf
As we have some vector layers on geographic coordinates WGS84 and a
Geocover tile for 18S,
I've set the project as 18S, enabled CRS reprojection on the fly, and set
the raster CRS to 18N. Unfortunately, QGIS does not display the
raster, even
selecting zoom to layer extent. (Using Mimas).
This is probably not a problem of QGIS, the Geocover projection is
just wrong,
but would like to know if there could be a way to circumvent this
problem to
be able to use GEOCOVER tiles of the S hemisphere within QGIS.
A way could be making a world file with the Georeferencer plugin, but
perhaps
there is a more general way.
Thanks
Agus
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