1

someone gave me a dataset with the three types of files, but when I load as a raster the png.files it doesn't show up on the maps. They ask me what SRC to take and I don't really know which one to choose, I tried a bunch (the one of the others layers, one that seems on my part of the world etc..) none seems to work. As I have the proper pjr and pgw files that go with it, why it doesn't read it as the geographic reference. .. Tried several things and read some to, but I still don't understand.

This is the content of the PGW files:

1.0000
0.0000
0.0000
-1.0000
240591.5000
4991759.5000

Prj file:

PROJCS["NAD83_/_MTM_zone_8",GEOGCS["NAD83_/_Géographique",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.2572221010,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0.0],UNIT["Decimal_Degree",0.01745329251994330]],PROJECTION["Transverse_Mercator"],PARAMETER["Latitude_Of_Center",0.0],PARAMETER["Longitude_Of_Origin",-73.5000000000],PARAMETER["Scale_Factor",0.9999000000],PARAMETER["False_Easting",304800.0],PARAMETER["False_Northing",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG","32188"]]

  • 1
    If the PGW is the "World" file, then it should be a simple text file with the information of the coordinates. Can you add the contents of that file to your question? Open it with a text editor, like Notepad, (or maybe Word...). – Spacedman Jan 12 '18 at 19:50
  • This is the content of the PGW files: 1.0000 0.0000 0.0000 -1.0000 240591.5000 4991759.5000 – Héloïse Piché-Couturier Jan 12 '18 at 20:06
  • What's in the .prj file? Do you also know the resolution (width x height) of the PNG? And where in the world should the image be? Do you know? – Spacedman Jan 12 '18 at 20:24
  • It's a small area 20 acres or so, located in southern Québec, Canada. The resolution of the PNG files is 614x516 pixels. I don't know what's in the prj.files, I don't know where to open it, Qgis say it's a unavalable layer. – Héloïse Piché-Couturier Jan 12 '18 at 20:32
  • 1
    Open a prj file in Word or Notepad or another text editor... – Spacedman Jan 12 '18 at 20:38
4

"MTM Zone 8" is the important thing here.

In QGIS, Load Raster, choose the .PNG and then set the CRS to "NAD 83(CSRS) MTM Zone 8" (EPSG code 2950). This puts your image just south-west of Montreal.

Its possible the Coordinate system isn't quite that, but QGIS won't read a .prj and apply it to a .png. But it looks right...

  • It work ! Thank you ! I'll read more carefully what they say in the prj next time! – Héloïse Piché-Couturier Jan 12 '18 at 22:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.