diff --git a/CHANGES b/CHANGES
index 2e4cd7796..2b2521039 100644
--- a/CHANGES
+++ b/CHANGES
@@ -212,6 +212,8 @@ Bugs fixed
 * #4477: Build fails after building specific files
 * #4449: apidoc: include "empty" packages that contain modules
 * #3917: citation labels are tranformed to ellipsis
+* #4501: graphviz: epub3 validation error caused if graph is not clickable
+* #4514: graphviz: workaround for wrong map ID which graphviz generates
 
 Testing
 --------
diff --git a/sphinx/builders/html.py b/sphinx/builders/html.py
index 2f8428989..2b2473e6c 100644
--- a/sphinx/builders/html.py
+++ b/sphinx/builders/html.py
@@ -188,6 +188,10 @@ class BuildInfo(object):
         return (self.config_hash == other.config_hash and
                 self.tags_hash == other.tags_hash)
 
+    def __ne__(self, other):  # type: ignore
+        # type: (BuildInfo) -> bool
+        return not (self == other)  # for py27
+
     def dump(self, f):
         # type: (IO) -> None
         f.write('# Sphinx build info version 1\n'
diff --git a/sphinx/ext/graphviz.py b/sphinx/ext/graphviz.py
index be1843e1e..2986bf9c1 100644
--- a/sphinx/ext/graphviz.py
+++ b/sphinx/ext/graphviz.py
@@ -37,13 +37,54 @@ if False:
 logger = logging.getLogger(__name__)
 
 
-mapname_re = re.compile(r'<map id="(.*?)"')
-
-
 class GraphvizError(SphinxError):
     category = 'Graphviz error'
 
 
+class ClickableMapDefinition(object):
+    """A manipulator for clickable map file of graphviz."""
+    maptag_re = re.compile('<map id="(.*?)"')
+    href_re = re.compile('href=".*?"')
+
+    def __init__(self, filename, content, dot=''):
+        # type: (unicode, unicode, unicode) -> None
+        self.id = None  # type: unicode
+        self.filename = filename
+        self.content = content.splitlines()
+        self.clickable = []  # type: List[unicode]
+
+        self.parse(dot=dot)
+
+    def parse(self, dot=None):
+        # type: (unicode) -> None
+        matched = self.maptag_re.match(self.content[0])   # type: ignore
+        if not matched:
+            raise GraphvizError('Invalid clickable map file found: %s' % self.filename)
+
+        self.id = matched.group(1)
+        if self.id == '%3':
+            # graphviz generates wrong ID if graph name not specified
+            # https://gitlab.com/graphviz/graphviz/issues/1327
+            hashed = sha1(dot.encode('utf-8')).hexdigest()
+            self.id = 'grapviz%s' % hashed[-10:]
+            self.content[0] = self.content[0].replace('%3', self.id)
+
+        for line in self.content:
+            if self.href_re.search(line):  # type: ignore
+                self.clickable.append(line)
+
+    def generate_clickable_map(self):
+        # type: () -> unicode
+        """Generate clickable map tags if clickable item exists.
+
+        If not exists, this only returns empty string.
+        """
+        if self.clickable:
+            return '\n'.join([self.content[0]] + self.clickable + [self.content[-1]])
+        else:
+            return ''
+
+
 class graphviz(nodes.General, nodes.Inline, nodes.Element):
     pass
 
@@ -253,18 +294,17 @@ def render_dot_html(self, node, code, options, prefix='graphviz',
             <p class="warning">%s</p></object>\n''' % (fname, alt)
             self.body.append(svgtag)
         else:
-            with open(outfn + '.map', 'rb') as mapfile:
-                imgmap = mapfile.readlines()
-            if len(imgmap) == 2:
-                # nothing in image map (the lines are <map> and </map>)
-                self.body.append('<img src="%s" alt="%s" %s/>\n' %
-                                 (fname, alt, imgcss))
-            else:
-                # has a map: get the name of the map and connect the parts
-                mapname = mapname_re.match(imgmap[0].decode('utf-8')).group(1)  # type: ignore
-                self.body.append('<img src="%s" alt="%s" usemap="#%s" %s/>\n' %
-                                 (fname, alt, mapname, imgcss))
-                self.body.extend([item.decode('utf-8') for item in imgmap])
+            with codecs.open(outfn + '.map', 'r', encoding='utf-8') as mapfile:  # type: ignore
+                imgmap = ClickableMapDefinition(outfn + '.map', mapfile.read(), dot=code)
+                if imgmap.clickable:
+                    # has a map
+                    self.body.append('<img src="%s" alt="%s" usemap="#%s" %s/>\n' %
+                                     (fname, alt, imgmap.id, imgcss))
+                    self.body.append(imgmap.generate_clickable_map())
+                else:
+                    # nothing in image map
+                    self.body.append('<img src="%s" alt="%s" %s/>\n' %
+                                     (fname, alt, imgcss))
         if 'align' in node:
             self.body.append('</div>\n')
 
diff --git a/tests/test_ext_graphviz.py b/tests/test_ext_graphviz.py
index 762add6f0..ef77135d7 100644
--- a/tests/test_ext_graphviz.py
+++ b/tests/test_ext_graphviz.py
@@ -13,6 +13,8 @@ import re
 
 import pytest
 
+from sphinx.ext.graphviz import ClickableMapDefinition
+
 
 @pytest.mark.sphinx('html', testroot='ext-graphviz')
 @pytest.mark.usefixtures('if_graphviz_found')
@@ -115,3 +117,63 @@ def test_graphviz_i18n(app, status, warning):
     content = (app.outdir / 'index.html').text()
     html = '<img src=".*?" alt="digraph {\n  BAR -&gt; BAZ\n}" />'
     assert re.search(html, content, re.M)
+
+
+def test_graphviz_parse_mapfile():
+    # empty graph
+    code = ('# digraph {\n'
+            '# }\n')
+    content = ('<map id="%3" name="%3">\n'
+               '</map>')
+    cmap = ClickableMapDefinition('dummy.map', content, code)
+    assert cmap.filename == 'dummy.map'
+    assert cmap.id == 'grapvizb08107169e'
+    assert len(cmap.clickable) == 0
+    assert cmap.generate_clickable_map() == ''
+
+    # normal graph
+    code = ('digraph {\n'
+            '  foo [href="http://www.google.com/"];\n'
+            '  foo -> bar;\n'
+            '}\n')
+    content = ('<map id="%3" name="%3">\n'
+               '<area shape="poly" id="node1" href="http://www.google.com/" title="foo" alt=""'
+               ' coords="77,29,76,22,70,15,62,10,52,7,41,5,30,7,20,10,12,15,7,22,5,29,7,37,12,'
+               '43,20,49,30,52,41,53,52,52,62,49,70,43,76,37"/>\n'
+               '</map>')
+    cmap = ClickableMapDefinition('dummy.map', content, code)
+    assert cmap.filename == 'dummy.map'
+    assert cmap.id == 'grapviza4ccdd48ce'
+    assert len(cmap.clickable) == 1
+    assert cmap.generate_clickable_map() == content.replace('%3', cmap.id)
+
+    # inheritance-diagram:: sphinx.builders.html
+    content = (
+        '<map id="inheritance66ff5471b9" name="inheritance66ff5471b9">\n'
+        '<area shape="rect" id="node1" title="Builds target formats from the reST sources."'
+        ' alt="" coords="26,95,125,110"/>\n'
+        '<area shape="rect" id="node5" title="Builds standalone HTML docs."'
+        ' alt="" coords="179,95,362,110"/>\n'
+        '<area shape="rect" id="node2" title="buildinfo file manipulator." '
+        ' alt="" coords="14,64,138,80"/>\n'
+        '<area shape="rect" id="node3" title="The container of stylesheets."'
+        ' alt="" coords="3,34,148,49"/>\n'
+        '<area shape="rect" id="node4" title="A StandaloneHTMLBuilder that creates all HTML'
+        ' pages as &quot;index.html&quot; in" alt="" coords="395,64,569,80"/>\n'
+        '<area shape="rect" id="node7" title="An abstract builder that serializes'
+        ' the generated HTML." alt="" coords="392,95,571,110"/>\n'
+        '<area shape="rect" id="node9" title="A StandaloneHTMLBuilder subclass that puts'
+        ' the whole document tree on one" alt="" coords="393,125,570,141"/>\n'
+        '<area shape="rect" id="node6" title="A builder that dumps the generated HTML'
+        ' into JSON files." alt="" coords="602,80,765,95"/>\n'
+        '<area shape="rect" id="node8" title="A Builder that dumps the generated HTML'
+        ' into pickle files." alt="" coords="602,110,765,125"/>\n'
+        '<area shape="rect" id="node10" title="The metadata of stylesheet."'
+        ' alt="" coords="11,3,141,19"/>\n'
+        '</map>'
+    )
+    cmap = ClickableMapDefinition('dummy.map', content, 'dummy_code')
+    assert cmap.filename == 'dummy.map'
+    assert cmap.id == 'inheritance66ff5471b9'
+    assert len(cmap.clickable) == 0
+    assert cmap.generate_clickable_map() == ''