Using GeoDatabases and GeoDataframes#

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import footbridge as ft

# large dataset of US National Highway System roads
# https://hepgis-usdot.hub.arcgis.com/datasets/dce9f09392eb474c8ad8e6a78416279b_0
fc = ft.FeatureClass("NHS.gdb/National_Highway_System__NHS_")
f"{len(fc)} rows"

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'492005 rows'

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# Set the CRS when creating the Feature Dataset
fds = ft.FeatureDataset(crs="EPSG:4326")
fds.crs.name

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'WGS 84'

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# The FeatureDataset will enforce the CRS
fds["NHS"] = fc

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# Or create an empty FeatureDataset, which has no CRS by default
fds = ft.FeatureDataset()
type(fds.crs)

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NoneType

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# The FeatureDataset sets its CRS from the first FeatureClass added
fds["NHS"] = fc
fds.crs.name

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'WGS 84'

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# FeatureDatasets can be added to more than one GeoDatabase
gdb1 = ft.GeoDatabase()
gdb1["NHS_dataset1"] = fds

gdb2 = ft.GeoDatabase()
gdb2["NHS_dataset2"] = fds
print(gdb1.fds_dict)
print(gdb2.fds_dict)
print("Note that the same object has different names ^")

{'NHS_dataset1': <footbridge._core.FeatureDataset object at 0x7fa8cc268380>}
{'NHS_dataset2': <footbridge._core.FeatureDataset object at 0x7fa8cc268380>}
Note that the same object has different names ^

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# Adding to the FeatureDataset updates it in both GeoDatabases
gdb1["NHS_dataset1"]["NHS_2"] = fc
print(gdb1.fc_dict)
print(gdb2.fc_dict)

{'NHS': <footbridge._core.FeatureClass object at 0x7fa8087dac10>, 'NHS_2': <footbridge._core.FeatureClass object at 0x7fa8087dac10>}
{'NHS': <footbridge._core.FeatureClass object at 0x7fa8087dac10>, 'NHS_2': <footbridge._core.FeatureClass object at 0x7fa8087dac10>}

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# Adding a FeatureClass directly to a FeatureDataset places it in the FeatureDataset named None
gdb1["NHS_fc2"] = fc
print(gdb1.fds_dict[None].fc_names)

['NHS_fc2']

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# FeatureClasses can be accessed as dicts, a list of names, or as a list of objects:
gdb1.fc_dict

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{'NHS': <footbridge._core.FeatureClass at 0x7fa8087dac10>,
 'NHS_2': <footbridge._core.FeatureClass at 0x7fa8087dac10>,
 'NHS_fc2': <footbridge._core.FeatureClass at 0x7fa8087dac10>}

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gdb1.fc_names

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['NHS', 'NHS_2', 'NHS_fc2']

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gdb1.fcs

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[<footbridge._core.FeatureClass at 0x7fa8087dac10>,
 <footbridge._core.FeatureClass at 0x7fa8087dac10>,
 <footbridge._core.FeatureClass at 0x7fa8087dac10>]

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# Which allows for easy access to FeatureClass functionality
for fc in gdb1.fcs:
    print(fc.crs.name)

WGS 84
WGS 84
WGS 84

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