#117: NAD27 to NAD83 Conversion Bug?

[starbuck]

Hi Frank,

Here are the Steps to re-produce:

Installed FWTools2.4.7.

Opened a command tool.

Typed: cs2cs +proj=utm +datum=NAD83 +zone=4 +to +proj=utm +datum=NAD27 +zone=4 +nadgrids=hawaii 635203.875 2352673.000 634918.69 2352882.53 -0.00

C:\Program Files\FWTools2.4.7>cs2cs +proj=utm +datum=NAD27 +zone=4 +to +proj=utm +datum=NAD83 +zone=4 +nadgrids=hawaii 634918.691 2352882.528 634629.26 2353369.24 0.00

The 27 to 83 conversion now produces values, but they do not match the 83 to 27 coordinates.

Windows Vista.

[starbuck]

Snap shot of command tool actions.

[starbuck]

Hi again,

Worked at it some more and have got it working.

THIS WORKS: '----------------------------------------------------------------------------------- cs2cs -v +proj=utm +datum=NAD83 +ellps=GRS80 +zone=4 +to +proj=utm +datum=NAD27 +ellps=clrk66 +zone=4 +nadgrids=hawaii # ---- From Coordinate System ---- #Universal Transverse Mercator (UTM) # Cyl, Sph # zone= south # +proj=utm +datum=NAD83 +ellps=GRS80 +zone=4 +towgs84=0,0,0 #--- following specified but NOT used # +ellps=GRS80 # ---- To Coordinate System ---- #Universal Transverse Mercator (UTM) # Cyl, Sph # zone= south # +proj=utm +datum=NAD27 +ellps=clrk66 +zone=4 +nadgrids=hawaii #--- following specified but NOT used # +ellps=clrk66 +nadgrids=conus,ntv1_can.dat 635203.875 2352673.000 634918.69 2352882.53 0.000 '-----------------------------------------------------------------------------------

THIS WORKS: '----------------------------------------------------------------------------------- cs2cs -v +proj=utm +datum=NAD27 +ellps=clrk66 +zone=4 +nadgrids=hawaii +to +proj=utm +datum=NAD83 +ellps=GRS80 +zone=4 # ---- From Coordinate System ---- #Universal Transverse Mercator (UTM) # Cyl, Sph # zone= south # +proj=utm +datum=NAD27 +ellps=clrk66 +zone=4 +nadgrids=hawaii #--- following specified but NOT used # +ellps=clrk66 +nadgrids=conus,ntv1_can.dat # ---- To Coordinate System ---- #Universal Transverse Mercator (UTM) # Cyl, Sph # zone= south # +proj=utm +datum=NAD83 +ellps=GRS80 +zone=4 +towgs84=0,0,0 #--- following specified but NOT used # +ellps=GRS80 634918.691 2352882.528 635203.87 2352673.00 0.000 '-----------------------------------------------------------------------------------

The parameter order was wrong in what I was doing.

So, I guess this can be closed.

Thanks for your help.

Cheers.