matching georeferenced jpg with GPS data in WGS84 [closed]

Question

I have imported my georeferenced jpg which I believe (on the basis of metadata in xmml file) to be in the NZGD2000 TM coordinate system.

metadata:

Origin:
  1.76759e+06,5.94938e+06
Pixel Size:
  1.08167,-1.08182
No Data Value
  -32768 
Data Type:
  GDT_Byte - Eight bit unsigned integer
Pyramid overviews:
Layer Spatial Reference System: 
  +proj=tmerc +lat_0=0 +lon_0=173 +k=0.9996 +x_0=1600000 +y_0=10000000 +ellps=GRS80                         +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
Layer Extent (layer original source projection): 
  1767594.1269140779040754,5946587.8368053492158651 :         1770700.6877073212526739,5949380.0231113545596600

the waypoint data layer from the GPS metadata:

General:
  Storage type of this layer: GPS eXchange file
Source for this layer: /Volumes/GARMIN/Garmin/GPX/Waypoints_19-JAN-13.gpx?type=waypoint
Geometry type of the features in this layer: Point
The number of features in this layer: 8
Editing capabilities of this layer: Add Features, Delete Features, Change Attribute Values
Extents:
  In layer spatial reference system units : xMin,yMin 174.891,-36.6086 : xMax,yMax         174.893,-36.6074
Layer Spatial Reference System:
  +proj=longlat +datum=WGS84 +no_defs

Clearly I need to convert the the GPS data to NZGD...

I first tried changing the coordinate system on GPS -- this displays the data on the GPS in correct coordinates but does not affect the exported data.

The import from GPS does not appear to allow one the specify any conversion.

I also tried changing the CRS of the layer but this does not appear to convert data just changes the interpretation of the existing coordinates.

Clearly I am missing something basic.

BTW using garmin's basecamp I was able to plot these points on google earth without problems so I know this is possible :)

Answer 1

You don't have to convert any data. QGIS can do that by itself. You can load different layers with different Coordinate reference systems (CRS), and let the project have another CRS. Just make sure that On-the-fly-projection is checked in Settings -> Project Settings, CRS tab.

GPX files are always in WGS84. So this layer should be in EPSG:4326. You can have the usual Google or Openstreetmap background with Openlayers plugin, requiring the Project CRS set to EPSG:3857.

For the raster file, EPSG:2193 should be the right one. You can ckeck each layers CRS by rightclick -> Set CRS for layer.