T0 - Add DOTNAME field¶

In this tutorial we show how to add a new field, "DOTNAME", to a shapefile. RasterToolkit often uses this field as part of the book-keeping.

In [1]:

import zipfile
import rastertoolkit
from pathlib import Path
from shapefile import Reader, Writer
from rastertoolkit.shape import plot_shapes, long_mult
from zenodo_client import Zenodo

print(f"rastertoolkit version v{rastertoolkit.__version__}")

import zipfile import rastertoolkit from pathlib import Path from shapefile import Reader, Writer from rastertoolkit.shape import plot_shapes, long_mult from zenodo_client import Zenodo print(f"rastertoolkit version v{rastertoolkit.__version__}")

rastertoolkit version v0.3.4

We will use Zenodo to download some shapefiles created for the report "A Climate Resilient Path for Ireland’s Marine Protected Areas Network". From the documentation:

These shapefiles summarise long-term patterns that emerge from the spatial-meta analysis of physical-biogeochemical and species distribution modelling data, providing an overview of the distribution of climate change refugia and climate change hotspots across Ireland's National Marine Planning Framework between 2026 - 2069, and across the two emissions scenarios considered in the report (RCP4.5 and RCP8.5).

In [2]:

# downlod and extract from zenodo
# https://zenodo.org/records/10790050
new_record = Zenodo().download_latest(
    10790050, "FairSeas_refugia_hotspots_shapefiles_2024.zip"
)
with zipfile.ZipFile(new_record, "r") as zip_ref:
    zip_ref.extractall(Path("./results") / new_record.stem)

# downlod and extract from zenodo # https://zenodo.org/records/10790050 new_record = Zenodo().download_latest( 10790050, "FairSeas_refugia_hotspots_shapefiles_2024.zip" ) with zipfile.ZipFile(new_record, "r") as zip_ref: zip_ref.extractall(Path("./results") / new_record.stem)

Here is some information about the shapefile and its associated metadata:

In [3]:

# original shapefile
shape_file = Path(
    "./results/FairSeas_refugia_hotspots_shapefiles_2024/FairSeas_pelagic_habitats_hotspots_80/FairSeas_pelagic_habitats_hotspots_80_new.shp"
)
sf = Reader(shape_file)

# number of records
num_records = len(sf.records())

# print the field names for the records
print(f"Number of records: {num_records}")
print("Fields in the original shapefile:")
print([field[0] for field in sf.fields[1:]])
print("For examples, the first record:")
print(sf.record(0).as_dict())

# original shapefile shape_file = Path( "./results/FairSeas_refugia_hotspots_shapefiles_2024/FairSeas_pelagic_habitats_hotspots_80/FairSeas_pelagic_habitats_hotspots_80_new.shp" ) sf = Reader(shape_file) # number of records num_records = len(sf.records()) # print the field names for the records print(f"Number of records: {num_records}") print("Fields in the original shapefile:") print([field[0] for field in sf.fields[1:]]) print("For examples, the first record:") print(sf.record(0).as_dict())

Number of records: 1
Fields in the original shapefile:
['lyr_1']
For examples, the first record:
{'lyr_1': -1}

But when we try to plot it using RasterToolkit plot_shapes function we get an error:

In [4]:

try:
    fig, ax = plot_shapes(shape_file)
except Exception as e:
    print(f"Error: {e}")

try: fig, ax = plot_shapes(shape_file) except Exception as e: print(f"Error: {e}")

Error: DOTNAME is not a field name

Here is an example of how to create a new shapefile with a DOTNAME field. Often you might want to combine meta data, for example if you had a shapefile of US counties you could create a "COUNTY.STATE" DOTNAME. In this example we only have one field so we'll just use that.

In [5]:

def add_dotname(shapefile, dotname_fields=["lyr_1"]):
    new_shape_file = shapefile.parent / (shapefile.stem + "_DN.shp")

    # shapefiles
    sf = Reader(shapefile)
    w = Writer(target=new_shape_file)

    # add the original fields
    for i, field in enumerate(sf.fields):
        if i > 0:
            w.field(*field)
    # add the new field
    w.field("DOTNAME", "C", 50)

    for i, shaperec in enumerate(sf.iterShapeRecords()):
        # add the new field
        w.record(
            *shaperec.record,
            ".".join([str(shaperec.record[field]).lower() for field in dotname_fields]),
        )
        # add the shape
        w.shape(shaperec.shape)
    w.close()
    sf.close()

    return new_shape_file


new_shape_file = add_dotname(shape_file, dotname_fields=["lyr_1"])

def add_dotname(shapefile, dotname_fields=["lyr_1"]): new_shape_file = shapefile.parent / (shapefile.stem + "_DN.shp") # shapefiles sf = Reader(shapefile) w = Writer(target=new_shape_file) # add the original fields for i, field in enumerate(sf.fields): if i > 0: w.field(*field) # add the new field w.field("DOTNAME", "C", 50) for i, shaperec in enumerate(sf.iterShapeRecords()): # add the new field w.record( *shaperec.record, ".".join([str(shaperec.record[field]).lower() for field in dotname_fields]), ) # add the shape w.shape(shaperec.shape) w.close() sf.close() return new_shape_file new_shape_file = add_dotname(shape_file, dotname_fields=["lyr_1"])

and now we can plot:

In [6]:

fig, ax = plot_shapes(new_shape_file)
ax.set_aspect(long_mult(0.5 * (sf.bbox[1] + sf.bbox[3])))

fig, ax = plot_shapes(new_shape_file) ax.set_aspect(long_mult(0.5 * (sf.bbox[1] + sf.bbox[3])))