13 georef

Working with GEOREF in Vgrid DGGS¶

Full Vgrid DGGS documentation is available at vgrid document.

To work with Vgrid DGGS directly in GeoPandas and Pandas, please use vgridpandas. Full Vgridpandas DGGS documentation is available at vgridpandas document.

To work with Vgrid DGGS in QGIS, install the Vgrid Plugin.

To visualize DGGS in Maplibre GL JS, try the vgrid-maplibre library.

For an interactive demo, visit the Vgrid Homepage.

Install vgrid¶

Uncomment the following line to install vgrid.

In [ ]:

# %pip install vgrid --upgrade

# %pip install vgrid --upgrade

latlon2georef¶

In [2]:

from vgrid.conversion.latlon2dggs import latlon2georef

lat = 10.775276
lon = 106.706797
res = 2
georef_id = latlon2georef(lat, lon, res)
georef_id

from vgrid.conversion.latlon2dggs import latlon2georef lat = 10.775276 lon = 106.706797 res = 2 georef_id = latlon2georef(lat, lon, res) georef_id

Out[2]:

'VGBL4246'

GEOREF to Polygon¶

In [3]:

from vgrid.conversion.dggs2geo.georef2geo import georef2geo
from vgrid.dggs.georef import decode

georef_geo = georef2geo(georef_id)
georef_geo

from vgrid.conversion.dggs2geo.georef2geo import georef2geo from vgrid.dggs.georef import decode georef_geo = georef2geo(georef_id) georef_geo

Out[3]:

GEOREF to GeoJSON¶

In [4]:

from vgrid.conversion.dggs2geo.georef2geo import georef2geojson

georef_geojson = georef2geojson(georef_id)
# georef_geojson

from vgrid.conversion.dggs2geo.georef2geo import georef2geojson georef_geojson = georef2geojson(georef_id) # georef_geojson

GEOREF Generator¶

In [15]:

from vgrid.generator.georefgrid import georefgrid
# georef_grid = georefgrid(resolution=1, output_format="geoparquet")
georef_grid = georefgrid(resolution=2,bbox=[104.03833902,8.53410125,111.92366325,12.80076792],output_format="parquet")
# georef_grid.plot(edgecolor="white")

from vgrid.generator.georefgrid import georefgrid # georef_grid = georefgrid(resolution=1, output_format="geoparquet") georef_grid = georefgrid(resolution=2,bbox=[104.03833902,8.53410125,111.92366325,12.80076792],output_format="parquet") # georef_grid.plot(edgecolor="white")

Generating GEOREF DGGS: 100%|██████████| 121818/121818 [00:09<00:00, 13119.96 cells/s]

Output file saved as: d:\Github\vgrid\docs\notebooks\georef_grid_2.parquet

GEOREF Inspect¶

In [1]:

from vgrid.stats.georefstats import georefinspect

resolution = 1
georef_inspect = georefinspect(resolution)
georef_inspect.head()

from vgrid.stats.georefstats import georefinspect resolution = 1 georef_inspect = georefinspect(resolution) georef_inspect.head()

Generating GEOREF DGGS: 100%|██████████| 64800/64800 [00:04<00:00, 13261.17 cells/s]

Out[1]:

	georef	resolution	center_lat	center_lon	cell_width	cell_height	cell_area	cell_perimeter	geometry	crossed	norm_area	ipq	zsc	cvh
0	AAAA00	1	-89.5	-179.5	0.000000	111693.864914	1.088612e+08	225337.031822	POLYGON ((-180 -90, -179 -90, -179 -89, -180 -...	False	0.013830	0.026941	0.164138	1.0
1	AAAB00	1	-88.5	-179.5	1949.301993	111693.177216	3.265476e+08	229233.654684	POLYGON ((-180 -89, -179 -89, -179 -88, -180 -...	False	0.041485	0.078091	0.279447	1.0
2	AAAC00	1	-87.5	-179.5	3897.998258	111691.802680	5.441267e+08	233127.086900	POLYGON ((-180 -88, -179 -88, -179 -87, -180 -...	False	0.069127	0.125813	0.354701	1.0
3	AAAD00	1	-86.5	-179.5	5845.483282	111689.743022	7.615267e+08	237016.121318	POLYGON ((-180 -87, -179 -87, -179 -86, -180 -...	False	0.096746	0.170349	0.412733	1.0
4	AAAE00	1	-85.5	-179.5	7791.151992	111687.000814	9.786761e+08	240899.553582	POLYGON ((-180 -86, -179 -86, -179 -85, -180 -...	False	0.124333	0.211922	0.460350	1.0

GEOREF Normalized Area Histogram¶

In [2]:

from vgrid.stats.georefstats import georef_norm_area_hist

georef_norm_area_hist(georef_inspect)

from vgrid.stats.georefstats import georef_norm_area_hist georef_norm_area_hist(georef_inspect)

Distribution of GEOREF Area Distortions¶

In [3]:

from vgrid.stats.georefstats import georef_norm_area

georef_norm_area(georef_inspect)

from vgrid.stats.georefstats import georef_norm_area georef_norm_area(georef_inspect)

GEOREF IPQ Compactness Histogram¶

Isoperimetric Inequality (IPQ) Compactness (suggested by Osserman, 1978):

$$C_{IPQ} = \frac{4 \pi A}{p^2}$$ The range of the IPQ compactness metric is [0,1].

A circle represents the maximum compactness with a value of 1.

As shapes become more irregular or elongated, their compactness decreases toward 0.

In [4]:

from vgrid.stats.georefstats import georef_compactness_ipq_hist

georef_compactness_ipq_hist(georef_inspect)

from vgrid.stats.georefstats import georef_compactness_ipq_hist georef_compactness_ipq_hist(georef_inspect)

Distribution of GEOREF IPQ Compactness¶

In [5]:

from vgrid.stats.georefstats import georef_compactness_ipq

georef_compactness_ipq(georef_inspect)

from vgrid.stats.georefstats import georef_compactness_ipq georef_compactness_ipq(georef_inspect)

GEOREF Convex hull Compactness Histogram:¶

$$C_{CVH} = \frac{A}{A_{CVH}}$$

The range of the convex hull compactness metric is [0,1].

As shapes become more concave, their convex hull compactness decreases toward 0.

In [6]:

from vgrid.stats.georefstats import georef_compactness_cvh_hist
georef_compactness_cvh_hist(georef_inspect)

from vgrid.stats.georefstats import georef_compactness_cvh_hist georef_compactness_cvh_hist(georef_inspect)

Distribution of GEOREF Convex hull Compactness¶

In [7]:

from vgrid.stats.georefstats import georef_compactness_cvh
georef_compactness_cvh(georef_inspect)

from vgrid.stats.georefstats import georef_compactness_cvh georef_compactness_cvh(georef_inspect)

GEOREF Statistics¶

Characteristic Length Scale (CLS - suggested by Ralph Kahn): the diameter of a spherical cap of the same cell's area

In [2]:

from vgrid.stats import georefstats

georefstats("m")

from vgrid.stats import georefstats georefstats("m")

Out[2]:

	resolution	number_of_cells	avg_edge_len_m	avg_cell_area_m2	cls_m
0	0	288	1.330812e+06	1.771061e+12	1.502531e+06
1	1	64800	8.872082e+04	7.871383e+09	1.001110e+05
2	2	233280000	1.478680e+03	2.186495e+06	1.668512e+03
3	3	23328000000	1.478680e+02	2.186495e+04	1.668512e+02
4	4	2332800000000	1.478680e+01	2.186495e+02	1.668512e+01
5	5	233280000000000	1.478680e+00	2.186495e+00	1.668512e+00
6	6	23328000000000000	1.478680e-01	2.186495e-02	1.668512e-01
7	7	233280000000000000000	1.478680e-03	2.186495e-06	1.668512e-03
8	8	23328000000000000000000	1.478680e-04	2.186495e-08	1.668512e-04
9	9	233280000000000000000000000	1.478680e-06	2.186495e-12	1.668512e-06
10	10	23328000000000000000000000000	1.478680e-07	2.186495e-14	1.668512e-07