created page for data editing

doc/source/tutorial-edit.rst

@@ -0,0 +1,50 @@
+.. _tutorial-edit:
+
+Editing rasters
+===============
+
+Setting 'no data' values
+------------------------
+
+The :func:`xarray.DataArray.where` function masks data by setting nans, as demonstrated by the example below.
+
+.. code:: python
+
+    import geowombat as gw
+    from geowombat.data import l8_224078_20200518
+
+    # Zeros are replaced with nans
+    with gw.open(l8_224078_20200518) as src:
+        data = src.where(src != 0)
+
+Setting 'no data' values with scaling
+-------------------------------------
+
+In GeoWombat, we use :func:`xarray.where` and :func:`xarray.DataArray.where` along with optional scaling in the :func:`set_nodata` function. In this example, we set zeros as 65535 and scale all other values from a [0,10000] range to [0,1].
+
+.. code:: python
+
+    import geowombat as gw
+    from geowombat.data import l8_224078_20200518
+
+    # Set the 'no data' value and scale all other values
+    with gw.open(l8_224078_20200518) as src:
+        data = src.gw.set_nodata(0, 65535, (0, 1), 'float64', scale_factor=0.0001)
+
+Replace values
+--------------
+
+The GeoWombat :func:`replace` function mimics :func:`pandas.DataFrame.replace`.
+
+.. code:: python
+
+    import geowombat as gw
+    from geowombat.data import l8_224078_20200518
+
+    # Replace 1 with 10
+    with gw.open(l8_224078_20200518) as src:
+        data = src.gw.replace({1: 10})
+
+.. note::
+
+    The :func:`replace` function is typically used with thematic data.