Can I access the raw coordinates?

Access to the raw coordinates of geometries stored in the geometry column is discouraged. If you make good use of the high-level transforms provided by the framework, you will be more productive.

Rigid motion

Coordinates are often called for when the application requires rigid motion. We provide optimized Translate, Rotate and Scale transforms for that purpose:

data = georef((; z=rand(1000, 1000)))
999990 rows omitted
1000000×2 GeoTable over 1000×1000 CartesianGrid
z geometry
Continuous Quadrangle
[NoUnits] 🖈 Cartesian{NoDatum}
0.80736 Quadrangle((x: 0.0 m, y: 0.0 m), ..., (x: 0.0 m, y: 1.0 m))
0.452412 Quadrangle((x: 1.0 m, y: 0.0 m), ..., (x: 1.0 m, y: 1.0 m))
0.960446 Quadrangle((x: 2.0 m, y: 0.0 m), ..., (x: 2.0 m, y: 1.0 m))
0.140258 Quadrangle((x: 3.0 m, y: 0.0 m), ..., (x: 3.0 m, y: 1.0 m))
0.701657 Quadrangle((x: 4.0 m, y: 0.0 m), ..., (x: 4.0 m, y: 1.0 m))
0.00734021 Quadrangle((x: 5.0 m, y: 0.0 m), ..., (x: 5.0 m, y: 1.0 m))
0.863883 Quadrangle((x: 6.0 m, y: 0.0 m), ..., (x: 6.0 m, y: 1.0 m))
0.681098 Quadrangle((x: 7.0 m, y: 0.0 m), ..., (x: 7.0 m, y: 1.0 m))
0.758812 Quadrangle((x: 8.0 m, y: 0.0 m), ..., (x: 8.0 m, y: 1.0 m))
0.567346 Quadrangle((x: 9.0 m, y: 0.0 m), ..., (x: 9.0 m, y: 1.0 m))
data |> Translate(10u"m", 8u"ft")
999990 rows omitted
1000000×2 GeoTable over 1000×1000 CartesianGrid
z geometry
Continuous Quadrangle
[NoUnits] 🖈 Cartesian{NoDatum}
0.80736 Quadrangle((x: 10.0 m, y: 2.4384 m), ..., (x: 10.0 m, y: 3.4384 m))
0.452412 Quadrangle((x: 11.0 m, y: 2.4384 m), ..., (x: 11.0 m, y: 3.4384 m))
0.960446 Quadrangle((x: 12.0 m, y: 2.4384 m), ..., (x: 12.0 m, y: 3.4384 m))
0.140258 Quadrangle((x: 13.0 m, y: 2.4384 m), ..., (x: 13.0 m, y: 3.4384 m))
0.701657 Quadrangle((x: 14.0 m, y: 2.4384 m), ..., (x: 14.0 m, y: 3.4384 m))
0.00734021 Quadrangle((x: 15.0 m, y: 2.4384 m), ..., (x: 15.0 m, y: 3.4384 m))
0.863883 Quadrangle((x: 16.0 m, y: 2.4384 m), ..., (x: 16.0 m, y: 3.4384 m))
0.681098 Quadrangle((x: 17.0 m, y: 2.4384 m), ..., (x: 17.0 m, y: 3.4384 m))
0.758812 Quadrangle((x: 18.0 m, y: 2.4384 m), ..., (x: 18.0 m, y: 3.4384 m))
0.567346 Quadrangle((x: 19.0 m, y: 2.4384 m), ..., (x: 19.0 m, y: 3.4384 m))

Projections

Map projections are examples of coordinate transforms. The Proj function can be used to "reproject" a GeoTable into a new coordinate reference system (CRS):

data |> Proj(Polar)
999990 rows omitted
1000000×2 GeoTable over 1000×1000 TransformedGrid
z geometry
Continuous Quadrangle
[NoUnits] 🖈 Polar{NoDatum}
0.80736 Quadrangle((ρ: 0.0 m, ϕ: 0.0 rad), ..., (ρ: 1.0 m, ϕ: 1.5708 rad))
0.452412 Quadrangle((ρ: 1.0 m, ϕ: 0.0 rad), ..., (ρ: 1.41421 m, ϕ: 0.785398 rad))
0.960446 Quadrangle((ρ: 2.0 m, ϕ: 0.0 rad), ..., (ρ: 2.23607 m, ϕ: 0.463648 rad))
0.140258 Quadrangle((ρ: 3.0 m, ϕ: 0.0 rad), ..., (ρ: 3.16228 m, ϕ: 0.321751 rad))
0.701657 Quadrangle((ρ: 4.0 m, ϕ: 0.0 rad), ..., (ρ: 4.12311 m, ϕ: 0.244979 rad))
0.00734021 Quadrangle((ρ: 5.0 m, ϕ: 0.0 rad), ..., (ρ: 5.09902 m, ϕ: 0.197396 rad))
0.863883 Quadrangle((ρ: 6.0 m, ϕ: 0.0 rad), ..., (ρ: 6.08276 m, ϕ: 0.165149 rad))
0.681098 Quadrangle((ρ: 7.0 m, ϕ: 0.0 rad), ..., (ρ: 7.07107 m, ϕ: 0.141897 rad))
0.758812 Quadrangle((ρ: 8.0 m, ϕ: 0.0 rad), ..., (ρ: 8.06226 m, ϕ: 0.124355 rad))
0.567346 Quadrangle((ρ: 9.0 m, ϕ: 0.0 rad), ..., (ρ: 9.05539 m, ϕ: 0.110657 rad))

Raw coordinates

If you really need access to the coordinates, use the coords function:

quad = data.geometry[1]
Quadrangle
├─ Point(x: 0.0 m, y: 0.0 m)
├─ Point(x: 1.0 m, y: 0.0 m)
├─ Point(x: 1.0 m, y: 1.0 m)
└─ Point(x: 0.0 m, y: 1.0 m)
point = centroid(quad)
Point with Cartesian{NoDatum} coordinates
├─ x: 0.5 m
└─ y: 0.5 m
coords(point)
Cartesian{NoDatum} coordinates
├─ x: 0.5 m
└─ y: 0.5 m

It returns a CRS object. The type of this object can be retrieved with the crs function, which works with any GeoTable, geospatial Domain or individual Geometry:

crs(data)
Cartesian2D{NoDatum, Quantity{Float64, 𝐋, FreeUnits{(m,), 𝐋, nothing}}} (alias for Cartesian{NoDatum, 2, Quantity{Float64, 𝐋, Unitful.FreeUnits{(m,), 𝐋, nothing}}})

Very often the coordinates are LatLon in degrees. These cannot be used in linear algebra routines. The function to converts any CRS object into a static vector with Cartesian coordinates for algebraic manipulation:

to(Point(LatLon(0, 0)))
Vec(6.378137e6 m, 0.0 m, 0.0 m)