BUG: Fix output file dtype in merge (#2450)

* Fix output file dtype in merge

Signed-off-by: Joao <joao@tesselo.com>

* Fix missing dtype in merge click call

* Update driver in creation_options in merge call

rasterio/merge.py

@@ -261,6 +261,7 @@ def merge(
     out_profile["height"] = output_height
     out_profile["width"] = output_width
     out_profile["count"] = output_count
+    out_profile["dtype"] = dt
     if nodata is not None:
         out_profile["nodata"] = nodata
 

rasterio/rio/merge.py

@@ -29,6 +29,7 @@ def deprecated_precision(*args):
               default='nearest', help="Resampling method.",
               show_default=True)
 @options.nodata_opt
+@options.dtype_opt
 @options.bidx_mult_opt
 @options.overwrite_opt
 @click.option(
@@ -40,8 +41,21 @@ def deprecated_precision(*args):
 )
 @options.creation_options
 @click.pass_context
-def merge(ctx, files, output, driver, bounds, res, resampling,
-          nodata, bidx, overwrite, precision, creation_options):
+def merge(
+    ctx,
+    files,
+    output,
+    driver,
+    bounds,
+    res,
+    resampling,
+    nodata,
+    dtype,
+    bidx,
+    overwrite,
+    precision,
+    creation_options,
+):
     """Copy valid pixels from input files to an output file.
 
     All files must have the same number of bands, data type, and
@@ -68,6 +82,8 @@ def merge(ctx, files, output, driver, bounds, res, resampling,
         files=files, output=output, overwrite=overwrite)
 
     resampling = Resampling[resampling]
+    if driver:
+        creation_options.update(driver=driver)
 
     with ctx.obj["env"]:
         merge_tool(
@@ -75,6 +91,7 @@ def merge(ctx, files, output, driver, bounds, res, resampling,
             bounds=bounds,
             res=res,
             nodata=nodata,
+            dtype=dtype,
             indexes=(bidx or None),
             resampling=resampling,
             dst_path=output,

tests/test_rio_merge.py

@@ -103,6 +103,21 @@ def test_data_dir_3(tmpdir):
     return tmpdir
 
 
+def test_rio_merge_dtype(test_data_dir_1, runner):
+    outputname = str(test_data_dir_1.join("merged.tif"))
+    inputs = [str(x) for x in test_data_dir_1.listdir()]
+    inputs.sort()
+
+    result = runner.invoke(
+        main_group, ["merge", "--dtype", "uint16"] + inputs + [outputname]
+    )
+    assert result.exit_code == 0
+    assert os.path.exists(outputname)
+
+    with rasterio.open(outputname) as out:
+        assert all(dt == "uint16" for dt in out.dtypes)
+
+
 def test_merge_with_colormap(test_data_dir_1, runner):
     outputname = str(test_data_dir_1.join('merged.tif'))
     inputs = [str(x) for x in test_data_dir_1.listdir()]