Added support to create PDS3Image object form numpy array.

refs planetarypy#60

planetaryimage/cubefile.py

@@ -31,6 +31,9 @@ class CubeFile(PlanetaryImage):
     def _save(self, file_to_write, overwrite):
         raise NotImplementedError
 
+    def _create_label(self, array):
+        raise NotImplementedError
+
     @property
     def _bands(self):
         return self.label['IsisCube']['Core']['Dimensions']['Bands']

planetaryimage/image.py

@@ -20,23 +20,26 @@ def open(cls, filename):
             Name of file to read as an image file.  This file may be gzip
             (``.gz``) or bzip2 (``.bz2``) compressed.
         """
-        if filename.endswith('.gz'):
-            fp = gzip.open(filename, 'rb')
-            try:
-                return cls(fp, filename, compression='gz')
-            finally:
-                fp.close()
-        elif filename.endswith('.bz2'):
-            fp = bz2.BZ2File(filename, 'rb')
-            try:
-                return cls(fp, filename, compression='bz2')
-            finally:
-                fp.close()
+        if isinstance(filename, numpy.ndarray):
+            return cls(filename, 'numpy_array')
         else:
-            with open(filename, 'rb') as fp:
-                return cls(fp, filename)
-
-    def __init__(self, stream, filename=None, compression=None):
+            if filename.endswith('.gz'):
+                fp = gzip.open(filename, 'rb')
+                try:
+                    return cls(fp, filename, compression='gz')
+                finally:
+                    fp.close()
+            elif filename.endswith('.bz2'):
+                fp = bz2.BZ2File(filename, 'rb')
+                try:
+                    return cls(fp, filename, compression='bz2')
+                finally:
+                    fp.close()
+            else:
+                with open(filename, 'rb') as fp:
+                    return cls(fp, filename)
+
+    def __init__(self, stream_or_array, filename=None, compression=None):
         """Create an Image object.
 
         Parameters
@@ -51,24 +54,30 @@ def __init__(self, stream, filename=None, compression=None):
         compression : string
             an optional string that indicate the compression type 'bz2' or 'gz'
         """
-        if isinstance(stream, six.string_types):
+        if isinstance(stream_or_array, six.string_types):
             error_msg = (
                 'A file like object is expected for stream. '
                 'Use %s.open(filename) to open a image file.'
             )
             raise TypeError(error_msg % type(self).__name__)
 
-        #: The filename if given, otherwise none.
-        self.filename = filename
+        if isinstance(stream_or_array, numpy.ndarray):
+            self.filename = 'numpy_array'
+            self.compression = None
+            self.data = stream_or_array
+            self.label = self._create_label(stream_or_array)
+        else:
+            #: The filename if given, otherwise none.
+            self.filename = filename
 
-        self.compression = compression
+            self.compression = compression
 
-        # TODO: rename to header and add footer?
-        #: The parsed label header in dictionary form.
-        self.label = self._load_label(stream)
+            # TODO: rename to header and add footer?
+            #: The parsed label header in dictionary form.
+            self.label = self._load_label(stream_or_array)
 
-        #: A numpy array representing the image
-        self.data = self._load_data(stream)
+            #: A numpy array representing the image
+            self.data = self._load_data(stream_or_array)
 
     def __repr__(self):
         # TODO: pick a better repr
@@ -155,6 +164,9 @@ def _load_data(self, stream):
         stream.seek(self.start_byte)
         return self._decode(stream)
 
+    def create_label(self, array):
+        self._create_label(array)
+
     def _decode(self, stream):
         return self._decoder.decode(stream)
 

planetaryimage/pds3image.py

@@ -165,6 +165,58 @@ def _save(self, file_to_write, overwrite):
             self.data.tofile(stream, format='%' + self.dtype.kind)
         stream.close()
 
+    def _create_label(self, array):
+        if len(array.shape) == 3:
+            bands = array.shape[0]
+            lines = array.shape[1]
+            line_samples = array.shape[2]
+        else:
+            bands = 1
+            lines = array.shape[0]
+            line_samples = array.shape[1]
+        record_bytes = line_samples * array.itemsize
+        label_module = pvl.PVLModule([
+            ('PDS_VERSION_ID', 'PDS3'),
+            ('RECORD_TYPE', 'FIXED_LENGTH'),
+            ('RECORD_BYTES', record_bytes),
+            ('LABEL_RECORDS', 1),
+            ('^IMAGE', 1),
+            ('IMAGE',
+                {'BANDS': bands,
+                 'LINES': lines,
+                 'LINE_SAMPLES': line_samples,
+                 'MAXIMUM': 0,
+                 'MEAN': 0,
+                 'MEDIAN': 0,
+                 'MINIMUM': 0,
+                 'SAMPLE_BITS': array.itemsize * 8,
+                 'SAMPLE_TYPE': 'MSB_INTEGER',
+                 'STANDARD_DEVIATION': 0})
+            ])
+        return self._update_label(label_module, array)
+
+    def _update_label(self, label, array):
+        maximum = float(numpy.max(array))
+        mean = numpy.mean(array)
+        median = numpy.median(array)
+        minimum = float(numpy.min(array))
+        stdev = numpy.std(array, ddof=1)
+
+        encoder = pvl.encoder.PDSLabelEncoder
+        serial_label = pvl.dumps(label, cls=encoder)
+        label_sz = len(serial_label)
+        image_pointer = int(label_sz / label['RECORD_BYTES']) + 1
+
+        label['^IMAGE'] = image_pointer + 1
+        label['LABEL_RECORDS'] = image_pointer
+        label['IMAGE']['MEAN'] = mean
+        label['IMAGE']['MAXIMUM'] = maximum
+        label['IMAGE']['MEDIAN'] = median
+        label['IMAGE']['MINIMUM'] = minimum
+        label['IMAGE']['STANDARD_DEVIATION'] = stdev
+
+        return label
+
     @property
     def _bands(self):
         return self.label['IMAGE'].get('BANDS', 1)