Convert GDA eastings/northings to WGS84 lat/long in QGIS

Question

I'm using QGIS to map weed locations and have a mixture of data from GPS, shapefiles of contours, OSM all in a project with CRS WGS84 (lat, long). I am trying to add in a shapefile I have been given which is in GDA eastings and northings but can't get it to mix with the other layers.

Lat for this area is ~-35, long about 149. Can't find an existing CRS definition that works - can get the right lat but the wrong long (~119). What do I do?

Hope this question makes sense as I'm pretty new to this GIS stuff.

Answer 1

A shapefile should usually have a .prj file with the projection information.

For GDA94, there are different projections available:

EPSG:3577 Australian Albers
EPSG:3112 Geoscience Australia Lambert
EPSG:3308 NSW Lambert
EPSG:3107 SA Lambert
EPSG:3111 Vicgrid94
EPSG:3113 BCSG02

and GDA94/MGA zone 48 to 58. From those, zone 55 should be the best choice.

If you are still unsure, look up the extent of the layer, as reported by properties, metadata tab, and include it in your question.