check blocksize and adapt if raster is too small

rio_cogeo/cogeo.py

@@ -2,6 +2,7 @@
 
 import os
 import sys
+import math
 import warnings
 import tempfile
 from contextlib import contextmanager
@@ -20,7 +21,7 @@
 import mercantile
 from supermercado.burntiles import tile_extrema
 
-from rio_cogeo.errors import LossyCompression
+from rio_cogeo.errors import LossyCompression, IncompatibleBlockRasterSize
 from rio_cogeo.utils import (
     get_maximum_overview_level,
     has_alpha_band,
@@ -122,6 +123,30 @@ def cog_translate(
                     LossyCompression,
                 )
 
+            tilesize = min(int(dst_kwargs["blockxsize"]), int(dst_kwargs["blockysize"]))
+
+            if src_dst.width < tilesize or src_dst.height < tilesize:
+                tilesize = 2 ** int(math.log(min(src_dst.width, src_dst.height), 2))
+                if tilesize < 64:
+                    warnings.warn(
+                        "Raster has dimension < 64px. Output COG cannot be tiled"
+                        " and overviews cannot be added.",
+                        IncompatibleBlockRasterSize,
+                    )
+                    dst_kwargs.pop("blockxsize", None)
+                    dst_kwargs.pop("blockysize", None)
+                    dst_kwargs.pop("tiled")
+                    overview_level = 0
+
+                else:
+                    warnings.warn(
+                        "Block Size are bigger than raster sizes. "
+                        "Setting blocksize to {}".format(tilesize),
+                        IncompatibleBlockRasterSize,
+                    )
+                    dst_kwargs["blockxsize"] = tilesize
+                    dst_kwargs["blockysize"] = tilesize
+
             vrt_params = dict(add_alpha=True)
 
             if nodata is not None:
@@ -141,9 +166,6 @@ def cog_translate(
                 )
                 center = [(bounds[0] + bounds[2]) / 2, (bounds[1] + bounds[3]) / 2]
 
-                tilesize = min(
-                    int(dst_kwargs["blockxsize"]), int(dst_kwargs["blockysize"])
-                )
                 lat = 0 if latitude_adjustment else center[1]
                 max_zoom = get_max_zoom(src_dst, lat=lat, tilesize=tilesize)
 
@@ -208,17 +230,11 @@ def cog_translate(
                                 mask_value = vrt_dst.dataset_mask(window=w)
                                 tmp_dst.write_mask(mask_value, window=w)
 
-                    if not quiet:
-                        click.echo("Adding overviews...", err=True)
-
                     if overview_level is None:
-                        overview_level = get_maximum_overview_level(
-                            vrt_dst,
-                            min(
-                                int(dst_kwargs["blockxsize"]),
-                                int(dst_kwargs["blockysize"]),
-                            ),
-                        )
+                        overview_level = get_maximum_overview_level(vrt_dst, tilesize)
+
+                    if not quiet and overview_level:
+                        click.echo("Adding overviews...", err=True)
 
                     overviews = [2 ** j for j in range(1, overview_level + 1)]
                     tmp_dst.build_overviews(

rio_cogeo/errors.py

@@ -7,3 +7,7 @@ class DeprecationWarning(UserWarning):
 
 class LossyCompression(UserWarning):
     """Rio-cogeo module Lossy compression warning."""
+
+
+class IncompatibleBlockRasterSize(UserWarning):
+    """Rio-cogeo module incompatible raster block/size warning."""

tests/test_cogeo.py

@@ -8,9 +8,9 @@
 from click.testing import CliRunner
 
 import rasterio
-from rio_cogeo.cogeo import cog_translate
+from rio_cogeo.cogeo import cog_translate, cog_validate
 from rio_cogeo.utils import has_mask_band, has_alpha_band
-from rio_cogeo.errors import LossyCompression
+from rio_cogeo.errors import LossyCompression, IncompatibleBlockRasterSize
 from rio_cogeo.profiles import cog_profiles
 
 from .conftest import requires_webp
@@ -32,6 +32,12 @@
 raster_path_mask = os.path.join(
     os.path.dirname(__file__), "fixtures", "image_rgb_mask.tif"
 )
+raster_path_small = os.path.join(
+    os.path.dirname(__file__), "fixtures", "image_171px.tif"
+)
+raster_path_toosmall = os.path.join(
+    os.path.dirname(__file__), "fixtures", "image_51px.tif"
+)
 
 jpeg_profile = cog_profiles.get("jpeg")
 jpeg_profile.update({"blockxsize": 64, "blockysize": 64})
@@ -41,6 +47,7 @@
 deflate_profile.update({"blockxsize": 64, "blockysize": 64})
 raw_profile = cog_profiles.get("raw")
 raw_profile.update({"blockxsize": 64, "blockysize": 64})
+default_profile = cog_profiles.get("raw")
 
 
 @pytest.fixture(autouse=True)
@@ -256,3 +263,32 @@ def test_cog_translate_tags():
             assert src.tags()["OVR_RESAMPLING_ALG"] == "NEAREST"
             assert src.tags()["DatasetName"] == "my useful dataset"
             assert src.descriptions[0] == "second band"
+
+
+def test_cog_translate_valid_blocksize():
+    """Should work as expected (create cogeo file)."""
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        with pytest.warns(IncompatibleBlockRasterSize):
+            cog_translate(raster_path_small, "cogeo.tif", default_profile, quiet=True)
+            assert cog_validate("cogeo.tif")
+            with rasterio.open("cogeo.tif") as src:
+                assert src.height == 171
+                assert src.width == 171
+                assert src.is_tiled
+                assert src.profile["blockxsize"] == 128
+                assert src.profile["blockysize"] == 128
+                assert src.overviews(1) == [2]
+
+        with pytest.warns(IncompatibleBlockRasterSize):
+            cog_translate(
+                raster_path_toosmall, "cogeo.tif", default_profile, quiet=True
+            )
+            assert cog_validate("cogeo.tif")
+            with rasterio.open("cogeo.tif") as src:
+                assert src.height == 51
+                assert src.width == 51
+                assert not src.is_tiled
+                assert not src.profile.get("blockxsize")
+                assert not src.profile.get("blockysize")
+                assert not src.overviews(1)