precalculating data projections

[Mark Mansour]

I'm not sure if this list is active, but I can't subscribe to the other
list so ... here goes...

I'm new to all things GIS and I need some help.

I've got data from two difference sources, one in GDA94 projection and
the other in AGD66 projection.  I have the original data in shapefile
but store them in PostGIS.

To get the data to align, I am doing an on-the-fly projection with
Mapserver (as defined in my .MAP file - see below).  What I would like
to do is actually transform the data so that when I do PostGIS SQL
statements everything still works.  I am also assuming that it would
be faster to precalculate/transform my data before I need it.

I attempted to transform the data using ogr2ogr with this command:
ogr2ogr -f "ESRI Shapefile" -s_srs "EPSG:4202" -t_srs "EPSG:4283"
transformed-loc500g.shp loc500g.shp

but it seems to make no difference.

Can anyone suggest either what I am doing wrong with ogr2ogr or an
alternative approach?


from my .map file
MAP
  NAME MyMap
  IMAGETYPE PNG
  EXTENT 144.96 -37.80 144.97 -37.83
  UNITS dd
  SIZE 500 250
  FONTSET "fonts/fonts.list"
  INTERLACE OFF

  PROJECTION
    "proj=longlat"
    "ellps=GRS80"
    "towgs84=0,0,0,0,0,0,0"
    "no_defs"
  END

  ...

LAYER
  NAME TOWNS_OUTLINE
  CONNECTIONTYPE postgis
  CONNECTION "user=postgres dbname=XXXX"
  DATA "the_geom from towns_outline"
  TYPE LINE
  STATUS DEFAULT

  CLASSITEM "loc_unique"
  LABELITEM "loc_unique"

  PROJECTION
    "proj=longlat"
    "ellps=aust_SA"
    "towgs84=-133,-48,148,0,0,0,0"
    "no_defs"
  END

  ...


and

from the EPSG file:
  <4202>
    proj=longlat
    ellps=aust_SA
    towgs84=-133,-48,148,0,0,0,0
    no_defs
  <>
  <4283>
    proj=longlat
    ellps=GRS80
    towgs84=0,0,0,0,0,0,0
    no_defs
  <>


Mark

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