"""
Merging two Fields
------------------

We can even generate the same field realisation on different grids. Let's try
to merge two unstructured rectangular fields.

"""

# sphinx_gallery_thumbnail_number = 2
import numpy as np

import gstools as gs

# creating our own unstructured grid
seed = gs.random.MasterRNG(19970221)
rng = np.random.RandomState(seed())
x = rng.randint(0, 100, size=10000)
y = rng.randint(0, 100, size=10000)

model = gs.Exponential(dim=2, var=1, len_scale=[12, 3], angles=np.pi / 8)
srf = gs.SRF(model, seed=20170519)
field1 = srf((x, y))
srf.plot()
###############################################################################
# But now we extend the field on the right hand side by creating a new
# unstructured grid and calculating a field with the same parameters and the
# same seed on it:

# new grid
seed = gs.random.MasterRNG(20011012)
rng = np.random.RandomState(seed())
x2 = rng.randint(99, 150, size=10000)
y2 = rng.randint(20, 80, size=10000)

field2 = srf((x2, y2))
ax = srf.plot()
ax.tricontourf(x, y, field1.T, levels=256)
ax.set_aspect("equal")

###############################################################################
# The slight mismatch where the two fields were merged is merely due to
# interpolation problems of the plotting routine. You can convince yourself
# be increasing the resolution of the grids by a factor of 10.
#
# Of course, this merging could also have been done by appending the grid
# point ``(x2, y2)`` to the original grid ``(x, y)`` before generating the field.
# But one application scenario would be to generate hugh fields, which would not
# fit into memory anymore.