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Convert NAD27(CGQ77) to WGS 84

Convert coordinates from NAD27(CGQ77) (EPSG:4609) to WGS 84 (EPSG:4326) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.

Direct link to this transformation: epsgtransform.com/transform/epsg-4609-to-epsg-4326

Official EPSG transformation from NAD27(CGQ77) to WGS 84

The EPSG Geodetic Parameter Dataset defines 1 transformation between NAD27(CGQ77) (EPSG:4609) and WGS 84 (EPSG:4326). Its parameters, accuracy and area of use are listed below.

NAD27(CGQ77) to WGS 84 (3)

EPSG:1691±1.5 m
Method:
NTv2
Area of use:
Canada - Quebec
Scope:
(null/copy) Approximation for medium and low accuracy applications assuming equality between plate-fixed static and earth-fixed dynamic CRSs, ignoring static/dynamic CRS differences.

Grid file: CQ77NA83.GSB

Parameter file is from NAD27(CGQ77) to NAD83 (2) (code 1575) assuming that NAD83(CSRS)v2 is equivalent to WGS 84 within the accuracy of the transformation.

Convert EPSG:4609 to EPSG:4326 in code

The same transformation with common GIS tools and libraries:

from pyproj import Transformer

transformer = Transformer.from_crs("EPSG:4609", "EPSG:4326", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)

Source: EPSG:4609 — NAD27(CGQ77)

geographic system using latitude and longitude on an ellipsoid · Area of use: Canada - Quebec

+proj=longlat +ellps=clrk66 +no_defs +type=crs
More about EPSG:4609 →

Target: EPSG:4326 — WGS 84

geographic system using latitude and longitude on an ellipsoid · Area of use: World (by country)

+proj=longlat +datum=WGS84 +no_defs +type=crs
More about EPSG:4326 →

Frequently asked questions

How accurate is converting NAD27(CGQ77) to WGS 84?
The most accurate official EPSG transformation between these systems is accurate to about ±1.5 m within its stated area of use. Browser-based converters approximate datum shifts with Helmert parameters; for surveying-grade work apply the official transformation (including the grid-shift files listed below) in a desktop GIS.
Does my data leave the browser when I use this converter?
No. All coordinate transformations are computed locally in your browser using proj4js. The coordinates you enter are never transmitted to any server.
Need the reverse? Convert EPSG:4326 to EPSG:4609 →