diff --git a/roentgen.py b/roentgen.py
index 9bc8ec5..a6ec43d 100644
--- a/roentgen.py
+++ b/roentgen.py
@@ -29,7 +29,7 @@ from roentgen.osm_getter import get_osm
 from roentgen.osm_reader import Map, OSMReader, OverpassReader
 from roentgen.point import Point
 from roentgen.scheme import LineStyle, Scheme
-from roentgen.ui import error, parse_options
+from roentgen.ui import parse_options
 from roentgen.util import MinMax
 
 
@@ -52,7 +52,7 @@ def main(options) -> None:
     else:
         content = get_osm(options.boundary_box, cache_path)
         if not content:
-            error("cannot download OSM data")
+            logging.fatal("Cannot download OSM data.")
             sys.exit(1)
         input_file_names = [cache_path / f"{options.boundary_box}.osm"]
 
diff --git a/roentgen/icon.py b/roentgen/icon.py
index ebea966..6e5707d 100644
--- a/roentgen/icon.py
+++ b/roentgen/icon.py
@@ -17,7 +17,6 @@ from svgwrite.container import Group
 from svgwrite.path import Path as SvgPath
 
 from roentgen.color import is_bright
-from roentgen.ui import error
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
@@ -241,7 +240,7 @@ class ShapeExtractor:
                 configuration, path, point, id_, name
             )
         else:
-            error(f"not standard ID {id_}")
+            logging.error(f"Not standard ID {id_}.")
 
     def get_shape(self, id_: str) -> Optional[Shape]:
         """
@@ -294,7 +293,9 @@ class ShapeSpecification:
             if "shape" in structure:
                 shape = extractor.get_shape(structure["shape"])
             else:
-                error("invalid shape specification: 'shape' key expected")
+                logging.error(
+                    "Invalid shape specification: `shape` key expected."
+                )
             if "color" in structure:
                 color = scheme.get_color(structure["color"])
             if "offset" in structure:
diff --git a/roentgen/osm_getter.py b/roentgen/osm_getter.py
index 6fb3790..574182e 100644
--- a/roentgen/osm_getter.py
+++ b/roentgen/osm_getter.py
@@ -7,10 +7,9 @@ import urllib
 from pathlib import Path
 from typing import Dict, Optional
 
+import logging
 import urllib3
 
-from roentgen.ui import error
-
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
@@ -37,7 +36,7 @@ def get_osm(
     )
 
     if not matcher:
-        error("invalid boundary box")
+        logging.fatal("Invalid boundary box.")
         return None
 
     try:
@@ -46,17 +45,17 @@ def get_osm(
         right = float(matcher.group("right"))
         top = float(matcher.group("top"))
     except ValueError:
-        error("parsing boundary box")
+        logging.fatal("Invalid boundary box.")
         return None
 
     if left >= right:
-        error("negative horizontal boundary")
+        logging.fatal("Negative horizontal boundary.")
         return None
     if bottom >= top:
-        error("negative vertical boundary")
+        logging.error("Negative vertical boundary.")
         return None
     if right - left > 0.5 or top - bottom > 0.5:
-        error("box too big")
+        logging.error("Boundary box is too big.")
         return None
 
     content = get_data(
diff --git a/roentgen/tile.py b/roentgen/tile.py
index ac3e4ba..9f9d240 100644
--- a/roentgen/tile.py
+++ b/roentgen/tile.py
@@ -20,7 +20,6 @@ from roentgen.mapper import Painter
 from roentgen.osm_getter import get_osm
 from roentgen.osm_reader import Map, OSMReader
 from roentgen.scheme import Scheme
-from roentgen.ui import error
 from roentgen.util import MinMax
 
 
@@ -101,7 +100,7 @@ class Tile:
         )
         content = get_osm(boundary_box, Path("cache"))
         if not content:
-            error("cannot download OSM data")
+            logging.error("Cannot download OSM data.")
             return None
 
         return OSMReader().parse_osm_file(cache_path / (boundary_box + ".osm"))
@@ -120,13 +119,17 @@ class Tile:
             f"https://tile.openstreetmap.org/{self.scale}/{self.x}/{self.y}.png"
         )
 
-    def draw(self, directory_name: Path, cache_path: Path):
+    def draw(self, directory_name: Path, cache_path: Path) -> None:
         """
         Draw tile to SVG file.
 
         :param directory_name: output directory to storing tiles
+        :param cache_path: directory to store temporary files
         """
         map_ = self.load_map(cache_path)
+        if map_ is None:
+            logging.fatal("No map to draw.")
+            return
 
         lat1, lon1 = self.get_coordinates()
         lat2, lon2 = Tile(self.x + 1, self.y + 1, self.scale).get_coordinates()
@@ -181,8 +184,7 @@ def ui(options) -> None:
         scale, x, y = map(int, options.tile.split("/"))
         tile = Tile(x, y, scale)
     else:
-        logging.fatal("specify either --coordinates, or --tile")
+        logging.fatal("Specify either --coordinates, or --tile.")
         sys.exit(1)
 
     tile.draw(directory, Path(options.cache))
-    print(tile.get_carto_address())
diff --git a/roentgen/ui.py b/roentgen/ui.py
index 0be0f8a..05475ca 100644
--- a/roentgen/ui.py
+++ b/roentgen/ui.py
@@ -4,8 +4,6 @@ Command-line user interface.
 import argparse
 import sys
 
-from typing import Optional
-
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
@@ -185,15 +183,3 @@ def progress_bar(
             f"{int(length - fill_length - 1) * ' '}▏{text}"
         )
         sys.stdout.write("\033[F")
-
-
-def error(message: Optional[str] = None):
-    """
-    Print error message.
-
-    :param message: message to print.
-    """
-    if message:
-        print(f"Error: {message}.")
-    else:
-        print("Error.")