diff --git a/masque/file/svg.py b/masque/file/svg.py
index 148f6d4..859c074 100644
--- a/masque/file/svg.py
+++ b/masque/file/svg.py
@@ -2,7 +2,7 @@
 SVG file format readers and writers
 """
 from collections.abc import Mapping
-import warnings
+import logging
 
 import numpy
 from numpy.typing import ArrayLike
@@ -12,6 +12,9 @@ from .utils import mangle_name
 from .. import Pattern
 
 
+logger = logging.getLogger(__name__)
+
+
 def writefile(
         library: Mapping[str, Pattern],
         top: str,
@@ -50,7 +53,7 @@ def writefile(
     bounds = pattern.get_bounds(library=library)
     if bounds is None:
         bounds_min, bounds_max = numpy.array([[-1, -1], [1, 1]])
-        warnings.warn('Pattern had no bounds (empty?); setting arbitrary viewbox', stacklevel=1)
+        logger.warning('Pattern had no bounds (empty?); setting arbitrary viewbox', stacklevel=1)
     else:
         bounds_min, bounds_max = bounds
 
@@ -117,7 +120,7 @@ def writefile_inverted(
     bounds = pattern.get_bounds(library=library)
     if bounds is None:
         bounds_min, bounds_max = numpy.array([[-1, -1], [1, 1]])
-        warnings.warn('Pattern had no bounds (empty?); setting arbitrary viewbox', stacklevel=1)
+        logger.warning('Pattern had no bounds (empty?); setting arbitrary viewbox', stacklevel=1)
     else:
         bounds_min, bounds_max = bounds