In reference to coats-of-arms for the Landis families
A coat-of-arms is typically a symbol of nobility, so most coats of arms
can be seen as an attempt to emulate noble descent and date back to the
18th and 19th century (there is no actual nobility in Switzerland, but
there are the so called regimental families). With the exception of a
certain Jacob Landys from Basel (
http://query.staatsarchiv.bs.ch/query/detail.aspx?Id=596199)
who might as well have other origins, no Landis belonged to the social elite
before industrialization, though there might still be a chance to find evidence
for a 15th century ancestor purchasing this coat-of-arms. In modern periods
they where usually granted to members of a guild. To this day it is possible
to register new coats of arms, because there are no legal regulations to it.
This is probably why there is a whole number of such coat-of-arms for the name Landis.
The source stated for the coat of arms you mentioned is: "Neues historisches Wappenbuch
der Stadt Zürich, by Jean Egli, 1860" (there is also a reprint of 2013):
http://www.chgh.net/heraldik/l/la/landisa.htm
The following website by the Zürich guild-committee, assigned with matters of heraldry,
explains the rules applying to the creation of a coat-of-arms (you might want to use
some online translation tool):
http://www.wappenkommission.ch/de/Dienstleistungen/FA-Heraldik
Mit besten Grüssen
Philipp
http://www.chgh.net/heraldik/l/la/landisf.htm
http://www.chgh.net/heraldik/l/la/landisg.htm
http://www.chgh.net/heraldik/l/la/landise.htm
http://www.chgh.net/heraldik/l/la/landisc.htm
http://www.chgh.net/heraldik/l/la/landisb.htm
http://www.chgh.net/heraldik/l/la/landis.htm