Examples

Reading a CSV

Some data is distributed as CSV files with WKT geometries in a custom column such as wkt. Something like

wkt,name
"POINT (30 10)","point1"

You can read such files as follows:

using GeoDataFrames
# Tell GDAL where to find the geometry column and not to keep it as a regular column (otherwise DataFrames will fail to parse it)
df =
GeoDataFrames.read("test.csv", options=["GEOM_POSSIBLE_NAMES=wkt", "KEEP_GEOM_COLUMNS=NO"])

The same can be achieved natively using the CSV.jl package. We need to wrap the WKT geometries using GeoFormatTypes.jl, so WellKnownGeometry can parse them automatically when needed later on.

using CSV
using WellKnownGeometry  # to parse GeoFormatTypes WKT geometries later on
using GeoFormatTypes

df = CSV.read("test.csv", DataFrame)
df.wkt =
    GeoFormatTypes.WellKnownText.((GeoFormatTypes.Geom(),), df.wkt)
GeoDataFrames.setgeometrycolumn!(df, :wkt)

Note that in both cases, we don't know the CRS, so it will be nothing by default. You can set it using setcrs! if you know it, but ideally we use better spatial file formats (such as Geopackage) that store the CRS natively.