I think that deeper, more profound answers require one to appeal to Linguistics. So I Googled "semantics of spanish prepositions" which revealed the following that should assist:
Huerta, Beth Lynn (2009). The semantics of the spanish prepositions en, a, and de: A cognitive approach (Order No. 3372152).
Available from ProQuest Dissertations & Theses A&I. (305085088).
Retrieved from http://search.proquest.com/docview/305085088?accountid=9851
At 24 pages, it is too long to reproduce here, but these details that should aid you to find it:
It is dated June 26, 2009, and
A dissertation submitted to the
Faculty of the Graduate School of the
University at Buffalo, State University of New York
in partial fulfillment of the requirements for the degree of
Doctor of Philosophy
A partial quote from p 11 of 24 (Abstract) should already convince you of and to evidence its helpfulness:
Prepositions are a source of error for English-speakers learning Spanish throughout many
years of study. Other than contrasts of
por
and
para
, very little emphasis is given to the
semantics of prepositions in current SLA pr
actices. However, a preposition in either
Spanish or English may have several meanings
associated with it which a native speaker
would know and use. Since prepositions in
both languages have multiple meanings which
do not entirely equate to the most similar pre
position in the other language, at times there
is a match (equivalency) and at other tim
es there is a mismatch between the two
languages. English-speaking learners of Spanis
h may attempt to equate the prepositions
across languages if unaware of the differences in spatial relations coded by the
prepositions in the two languages.
This dissertation examines the prepositions
en, a, and de in consideration of the
subset of spatial relations that they form within the Spanish language, their primary
meanings, and the semantic network of meanings associated with them. By using
illustrations and explanations of spatial relations for the three Spanish prepositions as
determined by Whitley, explanations of
the system provided by Bull, semantic
descriptions provided by the
Diccionario de la Real Academia Española
and the
Diccionario de Construcción y Ré
gimen de la Lengua Castellana
, and by applying the
model of principled polysemy
for analyzing English prepositions proposed by Tyler and
Evans, the current work provides a thorough description of
en
,
a
, and
de
from a cognitive perspective, that is, in terms of the
concepts
they convey. In order to provide a more complete analysis for the learner and educator, this work also includes a very brief
description of grammaticalized usages of these prepositions.