call .read() only once when dataset do not have nodata (#355)

* call .read() only once when dataset do not have nodata

* update changelog

CHANGES.md

@@ -1,3 +1,7 @@
+## 2.0.3 (2021-02-19)
+
+* Reduce the number of `.read()` calls for dataset without nodata value (https://github.com/cogeotiff/rio-tiler/pull/355)
+* replace deprecated `numpy.float` by `numpy.float64`
 
 ## 2.0.2 (2021-02-17)
 

rio_tiler/reader.py

@@ -81,19 +81,26 @@ def read(
         vrt_params.update(vrt_options)
 
     with WarpedVRT(src_dst, **vrt_params) as vrt:
-        data = vrt.read(
-            indexes=indexes, window=window, out_shape=out_shape, resampling=resampling,
-        )
         if ColorInterp.alpha in vrt.colorinterp:
             idx = vrt.colorinterp.index(ColorInterp.alpha) + 1
-            mask = vrt.read(
-                indexes=idx,
+            indexes = tuple(indexes) + (idx,)
+            if out_shape:
+                out_shape = (len(indexes), height, width)
+
+            data = vrt.read(
+                indexes=indexes,
                 window=window,
-                out_shape=mask_out_shape,
+                out_shape=out_shape,
                 resampling=resampling,
-                out_dtype="uint8",
             )
+            data, mask = data[0:-1], data[-1].astype("uint8")
         else:
+            data = vrt.read(
+                indexes=indexes,
+                window=window,
+                out_shape=out_shape,
+                resampling=resampling,
+            )
             mask = vrt.dataset_mask(
                 window=window, out_shape=mask_out_shape, resampling=resampling,
             )

rio_tiler/utils.py

@@ -262,7 +262,7 @@ def linear_rescale(
     imin, imax = in_range
     omin, omax = out_range
     image = numpy.clip(image, imin, imax) - imin
-    image = image / numpy.float(imax - imin)
+    image = image / numpy.float64(imax - imin)
     return image * (omax - omin) + omin
 
 

setup.py

@@ -20,7 +20,7 @@
 ]
 
 extra_reqs = {
-    "test": ["pytest", "pytest-benchmark", "pytest-cov", "rio-cogeo"],
+    "test": ["pytest", "pytest-asyncio", "pytest-benchmark", "pytest-cov", "rio-cogeo"],
     "dev": [
         "pytest",
         "pytest-benchmark",