How to know if a projection is correct?

Question

I have a tif with the following projection:

'+proj=stere +lat_0=1 +lon_0=2 +k=1 +x_0=6 +y_0=7 +datum=WGS84 +units=m +no_defs'

Geoserver doesn't accept these tifs and QGIS is unable to reproject them.

How do I know if this projection is ok and what do I do to correct it if not?

I add the gdalinfo output for reference:

Driver: GTiff/GeoTIFF
Files: xxxxx.tif
Size is 2751, 826
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Stereographic"],
    PARAMETER["latitude_of_origin",1],
    PARAMETER["central_meridian",2],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",6],
    PARAMETER["false_northing",7],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-18.500000000000000,46.500000000000000)
Pixel Size = (0.019992729916394,-0.019975786924939)
Metadata:
  AREA_OR_POINT=Area
Image Structure Metadata:
  COMPRESSION=LZW
  INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  ( -18.5000000,  46.5000000) (  1d59'59.21"E,  1d 0' 1.29"N)
Lower Left  ( -18.5000000,  30.0000000) (  1d59'59.21"E,  1d 0' 0.75"N)
Upper Right (  36.5000000,  46.5000000) (  2d 0' 0.99"E,  1d 0' 1.29"N)
Lower Right (  36.5000000,  30.0000000) (  2d 0' 0.99"E,  1d 0' 0.75"N)
Center      (   9.0000000,  38.2500000) (  2d 0' 0.10"E,  1d 0' 1.02"N)
Band 1 Block=2751x1 Type=Byte, ColorInterp=Red
Band 2 Block=2751x1 Type=Byte, ColorInterp=Green
Band 3 Block=2751x1 Type=Byte, ColorInterp=Blue

Answer 1

the easy way to check if the projection used is correct is to add reference data from another projection and visually check for consistency.

Based on the parameters of the projection, you can also verify that the projection is suitable for your area of interest. For instance, you have a stereographic projection tangent at lat/long (1,2), so if your data is not somewhere in Central Africa, then your projection is likely to be inappropriate.

What makes me think that there is a potential problem with your projection is the value of your false easting and northing (+x_0 and +y_0). With your unit being meters, a shift of 6 or 7 meters does not make sense. Those values could be degrees, so you should convert them into meter.

Answer 2

I created a TIFF with the same size, extent, and coordinate system with the following R code:

r = raster(matrix(2751*826, 826, 2751))
extent(r)=c(-18.5, 36.5, 30,46.5)
r[]=1:ncell(r)
projection(r)='+proj=stere +lat_0=1 +lon_0=2 +k=1 +x_0=6 +y_0=7 +datum=WGS84 +units=m +no_defs'
writeRaster(r, "stereo.tif")

And the gdalinfo looks the same:

$ gdalinfo stereo.tif 
Driver: GTiff/GeoTIFF
Files: stereo.tif
Size is 2751, 826
Coordinate System is:
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Stereographic"],
    PARAMETER["latitude_of_origin",1],
    PARAMETER["central_meridian",2],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",6],
    PARAMETER["false_northing",7],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-18.500000000000000,46.500000000000000)
Pixel Size = (0.019992729916394,-0.019975786924939)
Metadata:
  AREA_OR_POINT=Area
Image Structure Metadata:
  COMPRESSION=LZW
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  ( -18.5000000,  46.5000000) (  1d59'59.21"E,  1d 0' 1.29"N)
Lower Left  ( -18.5000000,  30.0000000) (  1d59'59.21"E,  1d 0' 0.75"N)
Upper Right (  36.5000000,  46.5000000) (  2d 0' 0.99"E,  1d 0' 1.29"N)
Lower Right (  36.5000000,  30.0000000) (  2d 0' 0.99"E,  1d 0' 0.75"N)
Center      (   9.0000000,  38.2500000) (  2d 0' 0.10"E,  1d 0' 1.02"N)
Band 1 Block=2751x1 Type=Float32, ColorInterp=Gray
  Min=1.000 Max=2272326.000 
  Minimum=1.000, Maximum=2272326.000, Mean=1136163.500, StdDev=655964.158
  NoData Value=-3.39999999999999996e+38
  Metadata:
    STATISTICS_MAXIMUM=2272326
    STATISTICS_MEAN=1136163.5
    STATISTICS_MINIMUM=1
    STATISTICS_STDDEV=655964.15823084

When loaded into QGIS it appears as a miniscule raster off the coast of Africa. If I right-click on the layer, choose "Set Layer CRS", and pick the EPSG 4326 CRS:

it reappears over the Mediterranean: