Return a 1x1 image when bbox is smaller than a single pixel (#637)

* Return a 1x1 image when bbox is smaller than a single pixel * update changelog --------- Co-authored-by: vincentsarago <[email protected]>
cogeotiff · Sep 13, 2023 · a272374 · a272374
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diff --git a/CHANGES.md b/CHANGES.md
@@ -1,3 +1,8 @@
+
+# 6.0.3 (2023-09-13)
+
+* return a 1x1 image when bbox is smaller than a single pixel (author @JackDunnNZ, https://github.com/cogeotiff/rio-tiler/pull/637)
+
 # 6.0.2 (2023-08-21)
 
 * Update `data_as_image` to return masked values (author @JackDunnNZ, https://github.com/cogeotiff/rio-tiler/pull/635)

diff --git a/rio_tiler/reader.py b/rio_tiler/reader.py
@@ -417,8 +417,8 @@ def part(
             max_size, round(window.height), round(window.width)
         )
 
-    height = height or round(window.height)
-    width = width or round(window.width)
+    height = height or max(1, round(window.height))
+    width = width or max(1, round(window.width))
 
     if buffer:
         bounds, height, width = _apply_buffer(buffer, bounds, height, width)

diff --git a/tests/test_reader.py b/tests/test_reader.py
@@ -5,6 +5,7 @@
 import numpy
 import pytest
 import rasterio
+from numpy.testing import assert_array_almost_equal
 from rasterio.warp import transform_bounds
 
 from rio_tiler import constants, reader
@@ -632,3 +633,11 @@ def test_part_no_VRT():
         assert img_pad.bounds == bounds_dst_crs
         # Padding should not have any influence when not doing any rescaling/reprojection
         numpy.array_equal(img_pad.data, img.data)
+
+        # Read bbox smaller than one pixel
+        bounds_small = [bounds[0], bounds[1], bounds[0] + 1e-6, bounds[1] + 1e-6]
+        bounds_small_dst_crs = transform_bounds("epsg:4326", src_dst.crs, *bounds_small)
+        img_small = reader.part(src_dst, bounds_small, bounds_crs="epsg:4326")
+        assert img_small.height == 1
+        assert img_small.width == 1
+        assert_array_almost_equal(img_small.bounds, bounds_small_dst_crs)