def from_xml_file(filename):
xmldoc = parse(filename)
width = get_track_root_info(xmldoc, 'width')
default_profil_steps_length = get_track_root_info(
xmldoc, 'profil steps length')
segments = []
for section in get_main_track(xmldoc).childNodes:
if section.nodeType == Node.ELEMENT_NODE:
s = Segment.from_xml(section)
if s.end_radius is None:
segments.append(s)
else:
profil_steps_length = default_profil_steps_length
if s.profil_steps_length is not None:
profil_steps_length = s.profil_steps_length
length = abs((s.radius + s.end_radius) / 2.0 * s.arc)
num_steps = int(length / profil_steps_length) + 1
if num_steps == 1:
segments.append(s)
else:
# rearange steps so:
# - every part of the turn has the same length
# - the first part has curvature given by ``radius``
# - the last part had curvature given by ``end_radius``
# - there are ``steps`` parts
# - the total ``arc`` angle does not change
dradius = (s.end_radius - s.radius) / float(num_steps -
1)
tmp = 0.0
for i in xrange(num_steps):
tmp += 1.0 / (s.radius + i * dradius)
geom_average = 1.0 / tmp
for i in xrange(num_steps):
name = s.name + '.' + str(i)
radius = s.radius + i * dradius
arc = s.arc * geom_average / radius
segments.append(
Segment(name=name,
arc=arc,
radius=radius,
end_radius=None))
return Track(segments, width)
def test_from_xml(self):
xmldoc = parseString("""
<section name="s6">
<attstr name="type" val="lft" />
<attnum name="arc" unit="deg" val="102.0" />
<attnum name="radius" unit="m" val="32.7" />
<attnum name="end radius" unit="m" val="38.4" />
<attnum name="grade" unit="%" val="-3.0" />
<attnum name="profil end tangent" unit="%" val="-3.0" />
<attnum name="profil steps length" unit="m" val="4.0" />
<attnum name="banking start" unit="deg" val="0.0"/>
<attnum name="banking end" unit="deg" val="-4.0"/>
<attstr name="marks" val="50;100;150"/>
<section name="Left Border">
<attnum name="width" unit="m" val="1.0" />
<attnum name="height" unit="m" val="0.05" />
<attstr name="surface" val="curb-left" />
<attstr name="style" val="curb" />
</section>
<section name="Left Side">
<attnum name="start width" unit="m" val="10.0" />
<attnum name="end width" unit="m" val="12.0" />
<attstr name="surface" val="dirtA" />
</section>
<section name="Right Side">
<attnum name="start width" unit="m" val="32.0" />
<attnum name="end width" unit="m" val="40.0" />
<attstr name="surface" val="sand" />
</section>
</section>
""")
s = Segment.from_xml(xmldoc.childNodes[0])
self.assertEqual(s.name, 's6')
self.assertIsNone(s.length)
self.assertAlmostEqual(math.degrees(s.arc), 102.0)
self.assertAlmostEqual(s.radius, 32.7)
self.assertAlmostEqual(s.end_radius, 38.4)
self.assertAlmostEqual(s.profil_steps_length, 4.0)
