Some documentation added

doc/rasters.rst

+Reading and writing raster files with Lmgeo
+===========================================
+
+The classes found in the formats subdirectory more or less have the same interface:
+
+*properties:*
+
+* nrows:     the number of rows
+* ncols:     the number of columns
+* dx:    the length of a pixel side on the ground in the X-direction
+* dy:    the length of a pixel side on the ground in the Y-direction
+* cellsize:      the width / height of a pixel on the ground; it is usually assumed that dx = dy
+* xll:   X-coordinate of the lower left corner of the raster
+* yll:   Y-coordinate of the lower left corner of the raster
+
+*methods:*
+
+* constructor, with two arguments indicating the relevant filename and the datatype (e.g. 'i' for integer and 'f' for float)
+* open(mode) with mode = 'r' - used to initialise the created instance for reading
+
+  The alternative value for mode is 'w' - used to initialise the created instance for writing:
+* open(mode, ncols, nrows, xll, yll, cellsize, nodatavalue) *(single band)*
+* open(mode, ncols, nrows, nbands, xll, yll, cellsize, nodatavalue) *(multiband)*
+
+* next() - used to cause the created instance to retrieve the values of the next row
+* reset(), to prepare the created instance for reading the file again from the beginning
+* writenext(sequence_with_data) - used to cause the created instance to write the values to file for the next line
+* flush(), to cause the created instance to really write the previously written data to disk
+* close(), to cause the created instance to close the file.
+
+*Example*::
+
+    from formats.asciigrid import AsciiGrid
+   
+    myraster = None
+    try:
+        fn = 'myraster.asc'
+        myraster = AsciiGrid(fn, 'i')
+        if not myraster.open('r'):
+            raise Exception('Cannot open file %s' % fn)
+        else:
+            for i in range(myraster.nrows):
+            line = myraster.next()
+            for k in range(myraster.ncols):
+                if line[k] == 42:
+                    print('Found!')
+                    break
+    finally:
+        if myraster is not None:
+            myraster.close()
+                
+                     
+
+Please note that Lmgeo supports a number of file formats which make use of separate header files. These often have the extension \*.hdr.
+This extension is usually added to the already existing name, so the header file of 'myraster.bil' becomes 'myraster.bil.hdr'. Some
+GIS software programmes do not follow this convention and rather expect a header file with name 'myraster.hdr'.
+
+*InMemoryRaster*
+
+The only class that has a slightly different interface is InMemoryRaster. When constructing an instance, the second argument is data. 
+It has to be specified either as None or as a sequence with data::
+
+    from formats.inmemoryraster import InMemoryRaster
+    
+    nrows, ncols = 100, 50
+    xll, yll = 0.0, 0.0
+    cellsize = 1.0
+    nodatavalue = -999
+    fn = 'dummy.asc'
+    inmemraster = InMemoryRaster(fn, None, 'i')
+    if not inmemraster.open('w', ncols, nrows, xll, yll, cellsize, nodatavalue):
+        raise Exception("Unable to initialise InMemoryRaster!")
+
+
+
+
+
+

doc/tools.rst

+Simple GIS operations with Lmgeo tools
+======================================
+
+A number of tools can be found in the subdirectory 'toolbox':
+
+* cliblib: for clipping from rasters
+* copylib: for copying a raster file to memory and to return it as InMemoryRaster
+* punchlib: for carrying out operations with a raster file and vector data, such as zonal statistics
+* scalelib: for scaling raster data
+* vcliplib: for clipping vector data along the edges of a boundary box, so that the vectors appear well when they are plotted.
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