From fbc3347f736f2397a94cf2f2fddecd0e64b49537 Mon Sep 17 00:00:00 2001
From: Sean Gillies <sean@mapbox.com>
Date: Wed, 7 Jan 2015 22:26:38 -0700
Subject: [PATCH] Logic and tests for merge without nodata.

Closes #240
---
 rasterio/rio/merge.py   | 28 ++++++++++++--------
 tests/test_rio_merge.py | 57 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 69 insertions(+), 16 deletions(-)

diff --git a/rasterio/rio/merge.py b/rasterio/rio/merge.py
index 80322ebf..d6e647cb 100644
--- a/rasterio/rio/merge.py
+++ b/rasterio/rio/merge.py
@@ -36,31 +36,39 @@ def merge(ctx, files, driver):
             with rasterio.open(files[0]) as first:
                 kwargs = first.meta
                 kwargs['transform'] = kwargs.pop('affine')
-                dest = np.empty((first.count,) + first.shape, 
+                dest = np.zeros((first.count,) + first.shape, 
                     dtype=first.dtypes[0])
 
+            nodataval = 0.0
             if os.path.exists(output):
                 dst = rasterio.open(output, 'r+')
-                nodataval = dst.nodatavals[0]
+                nodataval = dst.nodatavals[0] or nodataval
             else:
                 kwargs['driver'] == driver
                 dst = rasterio.open(output, 'w', **kwargs)
-                nodataval = first.nodatavals[0]
+                nodataval = first.nodatavals[0] or nodataval
 
-            dest.fill(nodataval)
+            if nodataval:
+                dest.fill(nodataval)
 
             for fname in reversed(files):
                 with rasterio.open(fname) as src:
                     data = src.read()
-                    np.copyto(dest, data,
-                        where=np.logical_and(
-                        dest==nodataval, data.mask==False))
+                    try:
+                        where = np.logical_and(
+                                dest==nodataval, data.mask==False)
+                    except AttributeError:
+                        where = dest==nodataval
+                    np.copyto(dest, data, where=where)
 
             if dst.mode == 'r+':
                 data = dst.read()
-                np.copyto(dest, data,
-                    where=np.logical_and(
-                    dest==nodataval, data.mask==False))
+                try:
+                    where = np.logical_and(
+                            dest==nodataval, data.mask==False)
+                except AttributeError:
+                    where = dest==nodataval
+                np.copyto(dest, data, where=where)
 
             dst.write(dest)
             dst.close()
diff --git a/tests/test_rio_merge.py b/tests/test_rio_merge.py
index 24ef19f8..03ed04aa 100644
--- a/tests/test_rio_merge.py
+++ b/tests/test_rio_merge.py
@@ -15,7 +15,7 @@ logging.basicConfig(stream=sys.stderr, level=logging.INFO)
 
 # Fixture to create test datasets within temporary directory
 @fixture(scope='function')
-def test_data_dir(tmpdir):
+def test_data_dir_1(tmpdir):
     kwargs = {
         "crs": {'init': 'epsg:4326'},
         "transform": (-114, 0.2, 0, 46, 0, -0.1),
@@ -28,12 +28,13 @@ def test_data_dir(tmpdir):
     }
 
     with rasterio.drivers():
-        with rasterio.open(str(tmpdir.join('one.tif')), 'w', **kwargs) as dst:
+
+        with rasterio.open(str(tmpdir.join('a.tif')), 'w', **kwargs) as dst:
             data = numpy.zeros((10, 10), dtype=rasterio.uint8)
             data[0:6, 0:6] = 255
             dst.write_band(1, data)
 
-        with rasterio.open(str(tmpdir.join('two.tif')), 'w', **kwargs) as dst:
+        with rasterio.open(str(tmpdir.join('b.tif')), 'w', **kwargs) as dst:
             data = numpy.zeros((10, 10), dtype=rasterio.uint8)
             data[4:8, 4:8] = 254
             dst.write_band(1, data)
@@ -41,9 +42,53 @@ def test_data_dir(tmpdir):
     return tmpdir
 
 
-def test_merge(test_data_dir):
-    outputname = str(test_data_dir.join('merged.tif'))
-    inputs = [str(x) for x in test_data_dir.listdir()]
+@fixture(scope='function')
+def test_data_dir_2(tmpdir):
+    kwargs = {
+        "crs": {'init': 'epsg:4326'},
+        "transform": (-114, 0.2, 0, 46, 0, -0.1),
+        "count": 1,
+        "dtype": rasterio.uint8,
+        "driver": "GTiff",
+        "width": 10,
+        "height": 10
+    }
+
+    with rasterio.drivers():
+
+        with rasterio.open(str(tmpdir.join('a.tif')), 'w', **kwargs) as dst:
+            data = numpy.zeros((10, 10), dtype=rasterio.uint8)
+            data[0:6, 0:6] = 255
+            dst.write_band(1, data)
+
+        with rasterio.open(str(tmpdir.join('b.tif')), 'w', **kwargs) as dst:
+            data = numpy.zeros((10, 10), dtype=rasterio.uint8)
+            data[4:8, 4:8] = 254
+            dst.write_band(1, data)
+
+    return tmpdir
+
+
+def test_merge_with_nodata(test_data_dir_1):
+    outputname = str(test_data_dir_1.join('merged.tif'))
+    inputs = [str(x) for x in test_data_dir_1.listdir()]
+    inputs.sort()
+    runner = CliRunner()
+    result = runner.invoke(merge, inputs + [outputname])
+    assert result.exit_code == 0
+    assert os.path.exists(outputname)
+    with rasterio.open(outputname) as out:
+        assert out.count == 1
+        data = out.read_band(1, masked=False)
+        expected = numpy.zeros((10, 10), dtype=rasterio.uint8)
+        expected[0:6, 0:6] = 255
+        expected[4:8, 4:8] = 254
+        assert numpy.all(data == expected)
+
+
+def test_merge_without_nodata(test_data_dir_2):
+    outputname = str(test_data_dir_2.join('merged.tif'))
+    inputs = [str(x) for x in test_data_dir_2.listdir()]
     inputs.sort()
     runner = CliRunner()
     result = runner.invoke(merge, inputs + [outputname])