pixel_type more explicit and extended

planetaryimage/image.py

@@ -60,6 +60,9 @@ def __init__(self, stream, filename=None, memory_layout='DISK'):
         #: A numpy array representing the image
         self.data = self._parse_data(stream)
 
+    def __repr__(self):
+        return self.filename
+
     @staticmethod
     def get_nested_dict(item, key_list):
         """Get value from nested dictionary using a key list. """
@@ -185,10 +188,8 @@ def format(self):
 
     @property
     def byte_order(self):
-        """Byte order in numpy format('>', '<', '=').
-        Defaults to msb.
-        """
-        return '>'
+        """Byte order in numpy format('>', '<', '=')."""
+        raise NotImplementedError
 
     @property
     def data_filename(self):

planetaryimage/pds3image.py

@@ -9,14 +9,15 @@ class PDS3Image(PlanetaryImage):
 
     """ A PDS3 image reader. """
 
-    PIXEL_TYPES = {
-        'UnsignedByte': numpy.dtype('uint8'),
-        'SignedByte': numpy.dtype('int8'),
-        'UnsignedWord': numpy.dtype('uint16'),
-        'SignedWord': numpy.dtype('int16'),
-        'UnsignedInteger': numpy.dtype('uint32'),
-        'SignedInteger': numpy.dtype('int32'),
-    }
+    LSB_INTEGER_TYPES = ['LSB_INTEGER', 'PC_INTEGER', 'VAX_INTEGER']
+    LSB_UNSIGNED_INTEGER_TYPES = ['LSB_UNSIGNED_INTEGER', 'PC_UNSIGNED_INTEGER',
+                                  'VAX_UNSIGNED_INTEGER']
+    MSB_INTEGER_TYPES = ['MSB_INTEGER', 'MAC_INTEGER', 'SUN_INTEGER', 'INTEGER']
+    MSB_UNSIGNED_INTEGER_TYPES = ['MSB_UNSIGNED_INTEGER', 'UNSIGNED_INTEGER',
+                                  'MAC_UNSIGNED_INTEGER', 'SUN_UNSIGNED_INTEGER'
+                                  ]
+    IEEE_REAL_TYPES = ['IEEE_REAL', 'MAC_REAL', 'SUN_REAL', 'REAL', 'FLOAT']
+    PC_REAL_TYPES = ['PC_REAL']
 
     LABEL_MAPPING = {
         'bands': ['IMAGE', 'BANDS'],
@@ -89,40 +90,54 @@ def format(self):
 
     @property
     def byte_order(self):
-        sample_type = self.get_nested_dict(
-            self.label, self.LABEL_MAPPING['sample_type'])
-        if "LSB" in sample_type:
-            return '<'
-        else:
-            return '>'
+        return self.data.dtype.byteorder
 
     @property
     def start_byte(self):
-        return self.parse_pointer(self.label['^IMAGE'], self.label['RECORD_BYTES'])[0]
+        return self.parse_pointer(
+            self.label['^IMAGE'], self.label['RECORD_BYTES']
+        )[0]
 
     @property
     def data_filename(self):
         return self.parse_pointer(self.label['^IMAGE'], 0)[1]
 
+    @property
+    def dtype(self):
+        """
+        Pixel data type overrides the implementation in PlanetaryImage
+        because PDS3 SAMPLE_TYPE expresses BOTH byte ordering and type.
+        Unlike ISIS CubeFile labels, which apparently express these as
+        separate label values.
+        """
+        return self.pixel_type
+
     @property
     def pixel_type(self):
-        sample_type = self.get_nested_dict(
-            self.label, self.LABEL_MAPPING['sample_type'])
-        bits = self.get_nested_dict(self.label, self.LABEL_MAPPING['bits'])
-
-        if 'UNSIGNED' in sample_type:
-            if bits == 8:
-                return self.PIXEL_TYPES['UnsignedByte']
-            if bits == 16:
-                return self.PIXEL_TYPES['UnsignedWord']
-            if bits == 32:
-                return self.PIXEL_TYPES['UnsignedInteger']
-        else:
-            if bits == 8:
-                return self.PIXEL_TYPES['SignedByte']
-            if bits == 16:
-                return self.PIXEL_TYPES['SignedWord']
-            if bits == 32:
-                return self.PIXEL_TYPES['SignedInteger']
+        sample_type = self.label['IMAGE']['SAMPLE_TYPE']
+        bits = self.label['IMAGE']['SAMPLE_BITS']
+        sample_bytes = str(int(bits / 8))  # get bytes to match NumPy dtype expressions
+
+        if sample_type in self.LSB_INTEGER_TYPES:
+            return numpy.dtype('<i' + sample_bytes)
+
+        if sample_type in self.LSB_UNSIGNED_INTEGER_TYPES:
+            return numpy.dtype('<u' + sample_bytes)
+
+        if sample_type in self.MSB_INTEGER_TYPES:
+            return numpy.dtype('>i' + sample_bytes)
+
+        if sample_type in self.MSB_UNSIGNED_INTEGER_TYPES:
+            return numpy.dtype('>u' + sample_bytes)
+
+        # I am guessing byte order by process of elimination
+        if sample_type in self.IEEE_REAL_TYPES:
+            return numpy.dtype('>f' + sample_bytes)
+
+        # The byte order used here worked properly for the HiRISE product
+        # DTEEC_008520_2085_009232_2085_A01.IMG
+        # I'd like a little better understand of this.
+        if sample_type in self.PC_REAL_TYPES:
+            return numpy.dtype('<f' + sample_bytes)
 
         raise TypeError

tests/test_pds3file.py

@@ -24,7 +24,7 @@ def test_pds3_1band_labels():
     assert image.lines == 10
     assert image.samples == 10
     assert image.format == 'BAND_SEQUENTIAL'
-    assert image.pixel_type == numpy.dtype('int16')
+    assert image.pixel_type == numpy.dtype('>i2')
     assert image.dtype == numpy.dtype('>i2')
     assert image.start_byte == 640
     assert image.shape == (1, 10, 10)