def extract(
path, fill_path, extent, no_data_value=999999, plot_fill=False, method="nearest", delta_limit=20.0, TOLERANCE=1e-3
):
r"""Extract sub-section of bathymetry from file at path
Function to extract a sub-section given by extent of the bathymetry file at
path assumed to be in a x,y,z format which can be unstructured. Uses the
bathymetry file at fill_path to fill in gaps in data. Returns the data
interpolated onto a grid determined by the resolution of the original file
or the limiting resolution delta_limit.
:Input:
*path* (string) - Path to the bathymetry file which the data is being
pulled from.
*fill_path* (string) - Path to the bathymetry file providing the fill data,
i.e. data to use when no data exists.
*extent* (tuple) - A tuple defining the rectangle of the sub-section. Must
be in the form (x lower,x upper,y lower, y upper).
*no_data_value* (float) - Value to use if no data was found to fill in a
missing value, ignored if `method = 'nearest'`.
Default is `999999`.
*method* (string) - Method for interpolation, valid methods are found in
the scipy module scipy.interpolate. Default is
`nearest`.
*delta_limit* (float) - Limit of finest horizontal resolution, default is
20 meters.
*tolerance* (float) - Tolerance allowed for extent matching. Since the
requested extents and the eventual output may not
match due to round off, this parameter is used to
check if they are within acceptable tolerances.
Default is `1e-3`.
:Output:
*Z* (ndarray) - Interpolated 2D array of bathymetry depths starting in the
upper right corner of the sub-section specified by extent.
*delta* (float) - Final choice used for the horizontal resolution.
"""
# Extract data
print "Loading data from file %s" % path
data = np.loadtxt(path)
points = []
values = []
dx = np.infty
dy = np.infty
print "Filtering data..."
for coordinate in data:
if extent[0] <= coordinate[0] <= extent[1]:
if extent[2] <= coordinate[1] <= extent[3]:
points.append(coordinate[0:2])
values.append(coordinate[2])
# Try to determine smallest dx and dy
if len(points) > 1:
if np.abs(points[-1][0] - points[-2][0]) < dx:
dx = np.abs(points[-1][0] - points[-2][0])
if np.abs(points[-1][1] - points[-2][1]) < dy:
dy = np.abs(points[-1][1] - points[-2][1])
if len(points) == 0:
raise Exception("No points were found inside requested extent.")
# Cast lists as ndarrays
points = np.array(points)
values = np.array(values)
# Create regularized grid
print "Computing grid data"
delta = max(min(dx, dy), meters2deg(delta_limit, 29.5)) # Limit to size of delta
N = (np.ceil((extent[1] - extent[0]) / delta), np.ceil((extent[3] - extent[2]) / delta))
print " delta = %s, N = %s" % (delta, N)
if N[0] > 2000 or N[1] > 2000:
raise Exception("Calculated resolution too high!")
x = np.linspace(extent[0], extent[1], N[0])
y = np.linspace(extent[2], extent[3], N[1])
X, Y = np.meshgrid(x, y)
# Check extents
if (
abs(x[0] - extent[0]) > TOLERANCE
or abs(x[-1] - extent[1]) > TOLERANCE
or abs(y[0] - extent[2]) > TOLERANCE
or abs(y[-1] - extent[3]) > TOLERANCE
):
raise Exception("Calculated grid out of extent tolerance.")
# Add fill data
print "Extracting fill data"
X_fill, Y_fill, Z_fill = bathy.read_topo(fill_path)
fill_extent = (np.min(X_fill), np.max(X_fill), np.min(Y_fill), np.max(Y_fill))
if (
fill_extent[0] > extent[0]
or fill_extent[1] < extent[1]
or fill_extent[2] > extent[2]
or fill_extent[3] < extent[3]
):
print " Fill Extent = %s" % str(fill_extent)
print " Requested Extent = %s" % str(extent)
raise Exception("Fill bathymetry extent does not contain extent.")
extent_mask = extent[0] > X_fill
extent_mask = np.logical_or(extent_mask, extent[1] < X_fill)
extent_mask = np.logical_or(extent_mask, extent[2] > Y_fill)
extent_mask = np.logical_or(extent_mask, extent[3] < Y_fill)
X_fill_mask = np.ma.masked_where(extent_mask, X_fill)
Y_fill_mask = np.ma.masked_where(extent_mask, Y_fill)
Z_fill_mask = np.ma.masked_where(extent_mask, Z_fill)
fill_points = np.column_stack((X_fill_mask.compressed(), Y_fill_mask.compressed()))
points = np.concatenate((points, fill_points))
values = np.concatenate((values, Z_fill_mask.compressed()))
if plot_fill:
fig = plt.figure(2)
axes = fig.add_subplot(111)
plot = axes.imshow(Z_fill_mask, vmin=np.min(Z_fill), vmax=np.max(Z_fill), extent=extent)
fig.colorbar(plot)
plt.show()
# Interpolate known points onto regularized grid
print "Creating interpolating function..."
Z = griddata(points, values, (X, Y), method=method, fill_value=no_data_value)
return Z, delta
def extract(path,
fill_path,
extent,
no_data_value=999999,
plot_fill=False,
method='nearest',
delta_limit=20.0,
TOLERANCE=1e-3):
r"""Extract sub-section of bathymetry from file at path
Function to extract a sub-section given by extent of the bathymetry file at
path assumed to be in a x,y,z format which can be unstructured. Uses the
bathymetry file at fill_path to fill in gaps in data. Returns the data
interpolated onto a grid determined by the resolution of the original file
or the limiting resolution delta_limit.
:Input:
*path* (string) - Path to the bathymetry file which the data is being
pulled from.
*fill_path* (string) - Path to the bathymetry file providing the fill data,
i.e. data to use when no data exists.
*extent* (tuple) - A tuple defining the rectangle of the sub-section. Must
be in the form (x lower,x upper,y lower, y upper).
*no_data_value* (float) - Value to use if no data was found to fill in a
missing value, ignored if `method = 'nearest'`.
Default is `999999`.
*method* (string) - Method for interpolation, valid methods are found in
the scipy module scipy.interpolate. Default is
`nearest`.
*delta_limit* (float) - Limit of finest horizontal resolution, default is
20 meters.
*tolerance* (float) - Tolerance allowed for extent matching. Since the
requested extents and the eventual output may not
match due to round off, this parameter is used to
check if they are within acceptable tolerances.
Default is `1e-3`.
:Output:
*Z* (ndarray) - Interpolated 2D array of bathymetry depths starting in the
upper right corner of the sub-section specified by extent.
*delta* (float) - Final choice used for the horizontal resolution.
"""
# Extract data
print "Loading data from file %s" % path
data = np.loadtxt(path)
points = []
values = []
dx = np.infty
dy = np.infty
print "Filtering data..."
for coordinate in data:
if extent[0] <= coordinate[0] <= extent[1]:
if extent[2] <= coordinate[1] <= extent[3]:
points.append(coordinate[0:2])
values.append(coordinate[2])
# Try to determine smallest dx and dy
if len(points) > 1:
if np.abs(points[-1][0] - points[-2][0]) < dx:
dx = np.abs(points[-1][0] - points[-2][0])
if np.abs(points[-1][1] - points[-2][1]) < dy:
dy = np.abs(points[-1][1] - points[-2][1])
if len(points) == 0:
raise Exception("No points were found inside requested extent.")
# Cast lists as ndarrays
points = np.array(points)
values = np.array(values)
# Create regularized grid
print "Computing grid data"
delta = max(min(dx, dy), meters2deg(delta_limit,
29.5)) # Limit to size of delta
N = (np.ceil((extent[1] - extent[0]) / delta),
np.ceil((extent[3] - extent[2]) / delta))
print " delta = %s, N = %s" % (delta, N)
if N[0] > 2000 or N[1] > 2000:
raise Exception("Calculated resolution too high!")
x = np.linspace(extent[0], extent[1], N[0])
y = np.linspace(extent[2], extent[3], N[1])
X, Y = np.meshgrid(x, y)
# Check extents
if abs(x[0] - extent[0]) > TOLERANCE or \
abs(x[-1] - extent[1]) > TOLERANCE or \
abs(y[0] - extent[2]) > TOLERANCE or \
abs(y[-1] - extent[3]) > TOLERANCE:
raise Exception("Calculated grid out of extent tolerance.")
# Add fill data
print "Extracting fill data"
X_fill, Y_fill, Z_fill = bathy.read_topo(fill_path)
fill_extent = (np.min(X_fill), np.max(X_fill), np.min(Y_fill),
np.max(Y_fill))
if fill_extent[0] > extent[0] or fill_extent[1] < extent[1] or \
fill_extent[2] > extent[2] or fill_extent[3] < extent[3]:
print " Fill Extent = %s" % str(fill_extent)
print " Requested Extent = %s" % str(extent)
raise Exception("Fill bathymetry extent does not contain extent.")
extent_mask = extent[0] > X_fill
extent_mask = np.logical_or(extent_mask, extent[1] < X_fill)
extent_mask = np.logical_or(extent_mask, extent[2] > Y_fill)
extent_mask = np.logical_or(extent_mask, extent[3] < Y_fill)
X_fill_mask = np.ma.masked_where(extent_mask, X_fill)
Y_fill_mask = np.ma.masked_where(extent_mask, Y_fill)
Z_fill_mask = np.ma.masked_where(extent_mask, Z_fill)
fill_points = np.column_stack(
(X_fill_mask.compressed(), Y_fill_mask.compressed()))
points = np.concatenate((points, fill_points))
values = np.concatenate((values, Z_fill_mask.compressed()))
if plot_fill:
fig = plt.figure(2)
axes = fig.add_subplot(111)
plot = axes.imshow(Z_fill_mask,
vmin=np.min(Z_fill),
vmax=np.max(Z_fill),
extent=extent)
fig.colorbar(plot)
plt.show()
# Interpolate known points onto regularized grid
print "Creating interpolating function..."
Z = griddata(points,
values, (X, Y),
method=method,
fill_value=no_data_value)
return Z, delta
def plot_bathy(paths, region_path, patch_edges=True, patch_names=True, names=None, plot_coastline=True):
r"""Plot the bathymetry files specified in paths and region_path."""
# Setup region figure
region_fig = plt.figure(1)
region_axes = region_fig.add_subplot(111)
# Setup patch figure
patch_fig = plt.figure(2)
columns = 3
rows = np.ceil(len(paths) / float(columns))
patch_axes = [patch_fig.add_subplot(rows, columns, i) for i in xrange(len(paths))]
# Read in region bathymetry
X, Y, Z = bathy.read_topo(region_path)
region_extent = (np.min(X), np.max(X), np.min(Y), np.max(Y))
depth_extent = (np.min(Z), np.max(Z))
# Create color map
cmap = colormaps.make_colormap(
{-1: [0.3, 0.2, 0.1], -0.00001: [0.95, 0.9, 0.7], 0.00001: [0.5, 0.7, 0], 1: [0.2, 0.5, 0.2]}
)
color_norm = colors.Normalize(depth_extent[0], depth_extent[1], clip=True)
# Plot region data
region_plot = region_axes.imshow(Z, vmin=depth_extent[0], vmax=depth_extent[1], extent=region_extent) # ,
# cmap=cmap,norm=color_norm)
if plot_coastline:
region_axes.contour(X, Y, Z, levels=[0.0], colors="r")
# Read in and plot each patch
for (i, patch_path) in enumerate(paths):
X, Y, Z = bathy.read_topo(patch_path)
extent = (np.min(X), np.max(X), np.min(Y), np.max(Y))
# Plot on region figure
region_axes.imshow(Z, vmin=depth_extent[0], vmax=depth_extent[1], extent=extent) # ,cmap=cmap,norm=color_norm)
# Plot boundaries of local bathy on region plot
if patch_edges:
# Bottom boundary
region_axes.plot((extent[0], extent[1]), (extent[2], extent[2]), "k")
# Upper boundary
region_axes.plot((extent[0], extent[1]), (extent[3], extent[3]), "k")
# Left boundary
region_axes.plot((extent[0], extent[0]), (extent[2], extent[3]), "k")
# Right boundary
region_axes.plot((extent[1], extent[1]), (extent[2], extent[3]), "k")
# Write name near edge
if names is None:
file_name = os.path.splitext(patch_path)[0]
else:
file_name = names[i]
if patch_names:
delta = X[0, 0] - X[1, 0]
region_axes.text(extent[0] + delta, extent[2] + delta, file_name, color="m")
# Plot on local bathy
patch_axes[i].imshow(
Z, vmin=depth_extent[0], vmax=depth_extent[1], extent=extent
) # ,cmap=cmap,norm=color_norm)
patch_axes[i].contour(X, Y, Z, levels=[0.0], colors="r")
patch_axes[i].set_title(file_name)
patch_axes[i].set_xlim(extent[0:2])
patch_axes[i].set_ylim(extent[2:])
patch_axes[i].set_xlabel("longitude")
patch_axes[i].set_ylabel("latitude")
# Output extents
print "Region %s: %s" % (file_name, extent)
# Fix up figures
region_axes.set_xlim(region_extent[0:2])
region_axes.set_ylim(region_extent[2:])
region_axes.set_title("Region")
# region_fig.colorbar(region_plot)
# patch_fig.colorbar(region_plot)
return region_fig, patch_fig
def plot_bathy(paths,
region_path,
patch_edges=True,
patch_names=True,
names=None,
plot_coastline=True):
r"""Plot the bathymetry files specified in paths and region_path."""
# Setup region figure
region_fig = plt.figure(1)
region_axes = region_fig.add_subplot(111)
# Setup patch figure
patch_fig = plt.figure(2)
columns = 3
rows = np.ceil(len(paths) / float(columns))
patch_axes = [
patch_fig.add_subplot(rows, columns, i) for i in xrange(len(paths))
]
# Read in region bathymetry
X, Y, Z = bathy.read_topo(region_path)
region_extent = (np.min(X), np.max(X), np.min(Y), np.max(Y))
depth_extent = (np.min(Z), np.max(Z))
# Create color map
cmap = colormaps.make_colormap({
-1: [0.3, 0.2, 0.1],
-0.00001: [0.95, 0.9, 0.7],
0.00001: [.5, .7, 0],
1: [.2, .5, .2]
})
color_norm = colors.Normalize(depth_extent[0], depth_extent[1], clip=True)
# Plot region data
region_plot = region_axes.imshow(Z,
vmin=depth_extent[0],
vmax=depth_extent[1],
extent=region_extent) #,
# cmap=cmap,norm=color_norm)
if plot_coastline:
region_axes.contour(X, Y, Z, levels=[0.0], colors='r')
# Read in and plot each patch
for (i, patch_path) in enumerate(paths):
X, Y, Z = bathy.read_topo(patch_path)
extent = (np.min(X), np.max(X), np.min(Y), np.max(Y))
# Plot on region figure
region_axes.imshow(Z,
vmin=depth_extent[0],
vmax=depth_extent[1],
extent=extent) #,cmap=cmap,norm=color_norm)
# Plot boundaries of local bathy on region plot
if patch_edges:
# Bottom boundary
region_axes.plot((extent[0], extent[1]), (extent[2], extent[2]),
'k')
# Upper boundary
region_axes.plot((extent[0], extent[1]), (extent[3], extent[3]),
'k')
# Left boundary
region_axes.plot((extent[0], extent[0]), (extent[2], extent[3]),
'k')
# Right boundary
region_axes.plot((extent[1], extent[1]), (extent[2], extent[3]),
'k')
# Write name near edge
if names is None:
file_name = os.path.splitext(patch_path)[0]
else:
file_name = names[i]
if patch_names:
delta = X[0, 0] - X[1, 0]
region_axes.text(extent[0] + delta,
extent[2] + delta,
file_name,
color='m')
# Plot on local bathy
patch_axes[i].imshow(Z,
vmin=depth_extent[0],
vmax=depth_extent[1],
extent=extent) #,cmap=cmap,norm=color_norm)
patch_axes[i].contour(X, Y, Z, levels=[0.0], colors='r')
patch_axes[i].set_title(file_name)
patch_axes[i].set_xlim(extent[0:2])
patch_axes[i].set_ylim(extent[2:])
patch_axes[i].set_xlabel('longitude')
patch_axes[i].set_ylabel('latitude')
# Output extents
print "Region %s: %s" % (file_name, extent)
# Fix up figures
region_axes.set_xlim(region_extent[0:2])
region_axes.set_ylim(region_extent[2:])
region_axes.set_title('Region')
# region_fig.colorbar(region_plot)
# patch_fig.colorbar(region_plot)
return region_fig, patch_fig
