added the ability to save ENVI headers and convert Python arrays to ENVI files

David Mayerich
1 parent f8af84f9
Showing 1 changed file with 46 additions and 4 deletions Show diff stats
python/envi.py
@@ -27,15 +27,15 @@ class envi_header:
         self.header_offset = int(0)
         self.data_type = int(4)
         self.interleave = "bsq"
-        self.sensor_type = ""
+        self.sensor_type = "Unknown"
         self.byte_order = int(0)
         self.x_start = int(0)
         self.y_start = int(0)
-        self.z_plot_titles = ""
+        self.z_plot_titles = "Unknown, Unknown"
         self.pixel_size = [float(0), float(0)]
         self.pixel_size_units = "Meters"
         self.wavelength_units = "Wavenumber"
-        self.description = ""
+        self.description = "no description"
         self.band_names = []
         self.wavelength = []
  
@@ -181,6 +181,35 @@ class envi_header:
             li += 1          
  
         f.close()
+
+    #save an ENVI header
+    def save(self, fname):
+    	f = open(fname, "w")
+    	f.write("ENVI\n")
+    	f.write("description = {" + self.description + "}" + "\n")
+    	f.write("samples = " + str(self.samples) + "\n")
+    	f.write("lines = " + str(self.lines) + "\n")
+    	f.write("bands = " + str(self.bands) + "\n")
+    	f.write("header offset = " + str(self.header_offset) + "\n")
+    	f.write("file type = ENVI Standard" + "\n")
+    	f.write("data type = " + str(self.get_envi_type(self.type)) + "\n")
+    	f.write("interleave = " + self.interleave + "\n")
+    	f.write("sensor type = " + self.sensor_type + "\n")
+    	f.write("byte order = " + str(self.byte_order) + "\n")
+    	f.write("x start = " + str(self.x_start) + "\n")
+    	f.write("y start = " + str(self.y_start) + "\n")
+    	f.write("wavelength units = " + self.wavelength_units + "\n")
+    	f.write("z plot titles = {" + self.z_plot_titles + "}" + "\n")
+
+    	f.close()
+
+    #sets the properties of the header to match those of the input array
+    def set(self, A):
+    	self.type = A.dtype
+    	self.samples = A.shape[2]
+    	self.lines = A.shape[1]
+    	self.bands = A.shape[0]
+
  
 class envi:
     def __init__(self, filename, headername = "", mask = []):
@@ -348,4 +377,17 @@ class envi:
         self.file.close()
  
     def __del__(self):
-        self.file.close()
 \ No newline at end of file
+        self.file.close()
+
+#saves an array as an ENVI file
+def save_envi(A, fname):
+    
+    #create and save a header file
+    header = envi_header();
+    header.set(A)
+    header.save(fname + ".hdr")
+
+    #save the raw data
+    file = open(fname, "wb")
+    file.write(bytearray(A))
+    file.close()
 \ No newline at end of file