Hi,
Thank you for the support
I couldn’t solve the issue yet
Please note that I have redone the work with updated SL99 information.
Still I have the same issue.
Earlier I have used projection parameters in the ogr2ogr command and this
time
the WKT based on a projection file which I am using regularly is used.
Detailed information is as follows
The content of the file :
SL99 WKT
PROJCS["SL_grid_99",
GEOGCS["GCS_Kandawala",
DATUM["D_Kandawala",
SPHEROID["Everest_1830",6377276.345,300.8017]],
PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",200000.000],
PARAMETER["False_Northing",200000.00],
PARAMETER["Central_Meridian",80.77171],
PARAMETER["Scale_Factor",0.9999238418],
PARAMETER["Latitude_Of_Origin",7.00048],
UNIT["Meter",1]]
Following command is used to project the vector data
ogr2ogr -a_srs slgrid99.wkt F:\UDAdata\test\cmc_b_sl99.shp
F:\UDAdata\test\cmc_bound.shp
Raster data’s original projection information is as follows ( from gdalinfo)
PROJCS["UTM Zone 44, Northern Hemisphere",
GEOGCS["WGS_1984",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.2572235630016],
TOWGS84[0,0,0,0,0,0,0]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]],
PROJECTION["Transverse_Mercator"],
PARAMETER["latitude_of_origin",0],
PARAMETER["central_meridian",81],
PARAMETER["scale_factor",0.9996],
PARAMETER["false_easting",500000],
PARAMETER["false_northing",0],
UNIT["Meter",1],
AUTHORITY["EPSG","32644"]]
Then I have used the following command to re-project raster data.
gdalwarp -t_srs slgrid99.wkt -s_srs "+proj=utm +zone=44 +ellps=WGS84
+datum=WGS84 +units=m" F:\UDAdata\po_310491_rgb_0000000_Clip.img F:\
UDAdata\test\raster_sl99.tiff
Then , when over layering I use the following custom projection in QGIS. It
worked fine with different vector data in the local context. This is the
first time I’m using raster data in my work.
+proj=tmerc +lat_0=7.00047 +lon_0=80.77171 +x_0=200000 +y_0=200000
+ellps=evrst30 +to_meter=0.999924 +units=m
The shift is around 200m.
WKT of the re projected files are as below
Vector
PROJCS["SL_grid_99",
GEOGCS["GCS_Kandawala",
DATUM["Kandawala",
SPHEROID["Everest_1830",6377276.345,300.8017]],
PRIMEM["Greenwich",0],
UNIT["Degree",0.017453292519943295]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",200000.000],
PARAMETER["False_Northing",200000.00],
PARAMETER["Central_Meridian",80.77171],
PARAMETER["Scale_Factor",0.9999238418],
PARAMETER["Latitude_Of_Origin",7.00048],
UNIT["Meter",1]]
Raster
PROJCS["SL_grid_99",
GEOGCS["GCS_Kandawala",
DATUM["unknown",
SPHEROID["unnamed",6377276.345,300.8017000000115]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["latitude_of_origin",7.00048],
PARAMETER["central_meridian",80.77171],
PARAMETER["scale_factor",0.9999238418],
PARAMETER["false_easting",200000],
PARAMETER["false_northing",200000],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]]]
Any clarification would be much appreciated.
Thanking you
nimalika
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