Geometry Fields¶
Geometry fields are distinguished from other fields. They are defined in ogr by the class osgeo.ogr.Geometry,
which has the following methods:
Methods returning a pandas Series or DataFrame:
- ExportToGML, ExportToIsoWkb, ExportToIsoWkt, ExportToJson, ExportToKML, ExportToWkb, ExportToWkt
- GetArea, GetBoundary, GetCoordinateDimension, GetCurveGeometry, GetDimension, GetEnvelope, GetEnvelope3D, GetGeometryCount, GetGeometryName, GetGeometryRef, GetGeometryType, GetLinearGeometry, GetM, GetPoint, GetPointCount, GetPointZM, GetPoint_2D, GetPoints, GetSpatialReference, GetX, GetY, GetZ, WkbSize
- Is3D, IsEmpty, IsMeasured, IsRing, IsSimple, IsValid
Methods returning a layer with attributes:
- ConvexHull, Buffer, Centroid, DelaunayTriangulation, Simplify, SimplifyPreserveTopology
- Contains, Crosses, Disjoint, Empty, Equal, Equals, Intersects, Overlaps, Touches, Within
- Difference, Intersect, Intersection, Segmentize, SymDifference, SymmetricDifference, Union
- Area, Boundary, CloseRings, CoordinateDimension, Destroy, Distance, Distance3D, FlattenTo2D, HasCurveGeometry, Length, PointOnSurface, Transform, TransformTo, UnionCascaded, Value
Methods requiring LayersUpdate or LayersWrite:
- AssignSpatialReference
- AddGeometry, AddGeometryDirectly, AddPoint, AddPointM, AddPointZM, AddPoint_2D
- Set3D, SetCoordinateDimension, SetMeasured, SetPoint, SetPointM, SetPointZM, SetPoint_2D
Note
Geometry methods return pandas Series or pandas DataFrame.
Export geometries¶
Geometries are exported as pandas DataFrame in the formats gml, isowkb, isowkt, json, kml, wkb, and wkt.
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.geometries_export() # equivalent to fmt='wkt', layer_number=0
Output:
FID
0 MULTIPOLYGON (((9.75168800354004 48.3219490051...
1 MULTIPOLYGON (((9.74722671508795 48.3244895935...
2 POLYGON ((9.82752799987793 48.4570274353028,9....
...
11299 POLYGON ((11.2021255493163 51.0652885437012,11...
11300 POLYGON ((11.3888244628907 51.0245742797852,11...
11301 POLYGON ((11.2615299224854 50.9376220703126,11...
Name: GEOM, Length: 11302, dtype: object
The example below compares data export in wkt and wkb. The latter is ca. 30 times faster [1] and requires ca. half storage size.
t0 = time.time()
df_wkt = lrs.geometries_export(fmt='wkt')
print 'WKT geometries: {dt} seconds'.format(dt=time.time()-t0)
t0 = time.time()
df_wkb = lrs.geometries_export(fmt='wkb')
print 'WKB geometries: {dt} seconds'.format(dt=time.time()-t0)
wkt_length = df_wkt.apply(lambda g: len(g)) # get the length of each wkt geometry string
wkb_length = df_wkb.apply(lambda g: len(g)) # get the length of each wkb geometry string
df = pd.concat([wkt_length, wkb_length, wkt_length/wkb_length], axis=1)
df.columns = ['wkt length', 'wkb length', 'length wkt/wkb']
print 'Lengths mean values:\n{}'.format(df.mean())
print 'Lengths standard deviations:\n{}'.format(df.std())
Output:
WKT geometries: 5.21000003815 seconds
WKB geometries: 0.160000085831 seconds
Lengths mean values:
wkt length 5795.756415
wkb length 2755.171474
length wkt/wkb 2.099449
dtype: float64
Lengths standard deviations:
wkt length 4935.985512
wkb length 2340.461718
length wkt/wkb 0.010039
dtype: float64
Geometry count¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_count()
Output:
FID
0 2
1 2
2 1
..
11299 1
11300 1
11301 1
Name: geom. count, Length: 11302, dtype: int64
Area¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
df = lrs.get_geometries_areas(data_frame=True)
print df
print 'Total area: {:.5}'.format(df['area'].sum())
Output:
area
FID
0 0.005590
1 0.000936
...
11299 0.001332
11300 0.000522
11301 0.010805
[11302 rows x 1 columns]
Total area: 45.92
Boundaries¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_boundaries(fmt='wkt')
Output:
FID
0 MULTILINESTRING ((9.75168800354004 48.32194900...
1 MULTILINESTRING ((9.74722671508795 48.32448959...
2 LINESTRING (9.82752799987793 48.4570274353028,...
...
11299 LINESTRING (11.2021255493163 51.0652885437012,...
11300 LINESTRING (11.3888244628907 51.0245742797852,...
11301 LINESTRING (11.2615299224854 50.9376220703126,...
Name: boundary, Length: 11302, dtype: object
Centroids¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_centroids()
Output:
x_center y_center
FID
0 9.708450 48.333522
1 9.772435 48.331778
2 9.771710 48.464195
... ... ...
11299 11.211392 51.085274
11300 11.372233 51.028024
11301 11.317872 50.978347
[11302 rows x 2 columns]
Coordinate dimensions¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_coordinate_dimensions().unique()
Curve geometry¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_curve_geometries()
Dimensions¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_dimensions().unique()
Envelopes¶
Envelope 2D
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_envelopes()
Output:
xmin xmax ymin ymax
0 9.618460 9.822202 48.298607 48.365326
1 9.743726 9.800255 48.319130 48.347599
2 9.716778 9.827528 48.433918 48.487774
... ... ... ... ...
11299 11.192033 11.231587 51.063351 51.104897
11300 11.351975 11.394562 51.018730 51.037430
11301 11.234882 11.402000 50.916714 51.036720
[11302 rows x 4 columns]
Envelope 3D
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_envelopes3D()
Output:
xmin xmax ymin ymax zmin zmax
0 9.618460 9.822202 48.298607 48.365326 0.0 0.0
1 9.743726 9.800255 48.319130 48.347599 0.0 0.0
2 9.716778 9.827528 48.433918 48.487774 0.0 0.0
... ... ... ... ... ... ...
11299 11.192033 11.231587 51.063351 51.104897 0.0 0.0
11300 11.351975 11.394562 51.018730 51.037430 0.0 0.0
11301 11.234882 11.402000 50.916714 51.036720 0.0 0.0
[11302 rows x 6 columns]
Names¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_geometries_names()
Output:
FID
0 MULTIPOLYGON
1 MULTIPOLYGON
2 POLYGON
...
11299 POLYGON
11300 POLYGON
11301 POLYGON
Name: geom_name, Length: 11302, dtype: object
Linear geometries¶
from girs.feat.layers import LayersReader
lrs = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs.get_linear_geometries()
X, Y, Z, and M¶
from girs.feat.layers import LayersRea from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
lrs1 = lrs0.centroid()
print pd.concat([
lrs1.get_geometries_x(),
lrs1.get_geometries_y(),
lrs1.get_geometries_z(),
lrs1.get_geometries_m()], axis=1)
Output:
x y z m
FID
0 9.708450 48.333522 0.0 0.0
1 9.772435 48.331778 0.0 0.0
2 9.771710 48.464195 0.0 0.0
... ... ... ... ...
11299 11.211392 51.085274 0.0 0.0
11300 11.372233 51.028024 0.0 0.0
11301 11.317872 50.978347 0.0 0.0
[11302 rows x 4 columns]
Points 2D¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
lrs1 = lrs0.centroid()
print lrs1.get_geometries_points_2d()
Output:
x y
FID
0 9.708450 48.333522
1 9.772435 48.331778
... ... ...
11299 11.211392 51.085274
11300 11.372233 51.028024
11301 11.317872 50.978347
[11302 rows x 2 columns]
Points¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
lrs1 = lrs0.centroid()
print lrs1.get_geometries_points()
Output:
x y z
FID
0 9.708450 48.333522 0.0
1 9.772435 48.331778 0.0
2 9.771710 48.464195 0.0
... ... ... ...
11299 11.211392 51.085274 0.0
11300 11.372233 51.028024 0.0
11301 11.317872 50.978347 0.0
[11302 rows x 3 columns]
Points ZM¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
lrs1 = lrs0.centroid()
print lrs1.get_geometries_points_zm()
Output:
x y z m
FID
0 9.708450 48.333522 0.0 0.0
1 9.772435 48.331778 0.0 0.0
2 9.771710 48.464195 0.0 0.0
... ... ... ... ...
11299 11.211392 51.085274 0.0 0.0
11300 11.372233 51.028024 0.0 0.0
11301 11.317872 50.978347 0.0 0.0
Spatial references¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.get_geometries_spatial_references()
WKB sizes¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.get_geometries_wkb_size()
Is geometry 3D¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_3d().value_counts()
Is geometry empty¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_empty().value_counts()
Is geometry measured¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_measured().value_counts()
Is geometry point¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_point()
Is geometry polygon¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_polygon().value_counts()
Is geometry ring¶
from girs.feat.layers import LayersReader
lrs0 = LayersReader('D:/tmp/girs/DEU_adm_shp/DEU_adm4.shp')
print lrs0.is_geometry_ring().value_counts()