1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
##############################################################################
#
# Copyright (c) 2003-2018 by The University of Queensland
# http://www.uq.edu.au
#
# Primary Business: Queensland, Australia
# Licensed under the Apache License, version 2.0
# http://www.apache.org/licenses/LICENSE-2.0
#
# Development until 2012 by Earth Systems Science Computational Center (ESSCC)
# Development 2012-2013 by School of Earth Sciences
# Development from 2014 by Centre for Geoscience Computing (GeoComp)
#
##############################################################################
"""This example shows how to display ER Mapper raster data with matplotlib"""
from __future__ import division, print_function
import matplotlib
# The following line is here to allow automated testing. Remove or comment if
# you would like to display the final plot in a window instead.
matplotlib.use('agg')
from matplotlib import pyplot as plt
import numpy as np
import sys
# input filename
if len(sys.argv)>1:
FILENAME=sys.argv[1]
else:
FILENAME='data/QLDWestGravity.ers'
if FILENAME[-4:]=='.ers': FILENAME=FILENAME[:-4]
ersfn=FILENAME+'.ers'
metadata=open(ersfn,'r').readlines()
# parse metadata
start=-1
for i in range(len(metadata)):
if metadata[i].strip() == 'DatasetHeader Begin':
start=i+1
if start==-1:
raise RuntimeError('Invalid ERS file (DatasetHeader not found)')
md_dict={}
section=[]
for i in range(start, len(metadata)):
line=metadata[i].strip()
if line[-6:].strip() == 'Begin':
section.append(line[:-6].strip())
elif line[-4:].strip() == 'End':
if len(section)>0:
section.pop()
else:
vals=line.split('=')
if len(vals)==2:
key = vals[0].strip()
value = vals[1].strip()
fullkey='.'.join(section+[key])
md_dict[fullkey]=value
try:
if md_dict['RasterInfo.CellType'] == 'IEEE4ByteReal':
datatype=np.float32
elif md_dict['RasterInfo.CellType'] == 'IEEE8ByteReal':
datatype=np.float64
elif md_dict['RasterInfo.CellType'] == 'Signed32BitInteger':
datatype=np.int32
else:
raise RuntimeError('Unsupported data type '+md_dict['RasterInfo.CellType'])
except KeyError:
print("Cell type not specified. Assuming IEEE4ByteReal.")
datatype=np.float32
try:
NX = int(md_dict['RasterInfo.NrOfCellsPerLine'])
NY = int(md_dict['RasterInfo.NrOfLines'])
except:
raise RuntimeError("Could not determine extents of data")
try:
spacingX = float(md_dict['RasterInfo.CellInfo.Xdimension'])
spacingY = float(md_dict['RasterInfo.CellInfo.Ydimension'])
except:
raise RuntimeError("Could not determine cell dimensions")
try:
if md_dict['CoordinateSpace.CoordinateType']=='EN':
originX = float(md_dict['RasterInfo.RegistrationCoord.Eastings'])
originY = float(md_dict['RasterInfo.RegistrationCoord.Northings'])
labelX = "Easting"
labelY = "Northing"
elif md_dict['CoordinateSpace.CoordinateType']=='LL':
originX = float(md_dict['RasterInfo.RegistrationCoord.Longitude'])
originY = float(md_dict['RasterInfo.RegistrationCoord.Latitude'])
labelX = "Longitude"
labelY = "Latitude"
else:
raise RuntimeError("Unknown CoordinateType")
except:
self.logger.warn("Could not determine coordinate origin. Setting to (0.0, 0.0)")
originX,originY = 0.0, 0.0
f=open(FILENAME,'r')
longitude=np.linspace(originX, originX+spacingX*NX, NX, endpoint=True)
latitude=np.linspace(originY, originY-spacingY*NY, NY, endpoint=True)
DATA=np.fromfile(FILENAME, dtype=datatype).reshape(NY, NX)
# flip data in y-direction since ER Mapper stores data bottom up
DATA=np.flipud(DATA)
x,y=np.meshgrid(longitude, latitude)
plt.figure(figsize=(6*(spacingX*NX/(spacingY*NY))+1, 6), dpi=100)
plt.pcolor(x, y, DATA)
locs,_=plt.xticks()
plt.xticks(locs, list(map(lambda x:"%g"%x, locs)))
plt.xlabel(labelX)
plt.ylabel(labelY)
plt.axis('tight')
plt.title(FILENAME)
plt.colorbar()
plt.show()
plt.savefig("ermapper_plot.png")
|
