I think the full phrase makes things a bit different from what I'd previously assumed... So I'm entering a new answer as I'm picking a different word (hope that's ok?).

Given the context, I would actually keep the "patriotic" bit, and translate "immaginario" as "heritage" - I think it's more specific to the context of names and renaming the peaks, "heritage" can also have this extra meaning of something geographical, a landmark, etc.

See:

1) http://www.helsinki.fi/maantiede/geofi/fennia/Fennia_178_1.h...
----- Landscaping the patriotic past: Finnish war landscapes as a national heritage
The landscapes of war and conflict — such as battlefields, relics of military constructions and memorials — are fundamental parts of the national iconography of modern states. (...) The remains of old battlefields in Eastern and Northern Finland and hundreds of war memorials and cemeteries all over the country are part of the local historical landscape and thus a part of the local memory and heritage. These landscapes are also an essential part of the processes of preservation, re-creation and representation of contemporary heritage-making and the tourism that has become attached to it. A new kind of patriotic heritage-making has also emerged in Finland (...) -----

(Actually I think "iconography" wouldn't be a bad alternative either, but I prefer "heritage".)


2) http://www.cityofhenderson.com/news/php/newstemplate.php?pag...
----- The Memorial Wall is just one way that Henderson honors its patriotic heritage. -----


3) http://thomas.loc.gov/cgi-bin/query/z?r104:E29SE5-163:
----- Mr. Speaker, I rise today in honor and recognition of Columbus Day and in celebration of Italian-American heritage. (...) Happy Columbus Day to my fellow Italian-Americans as they celebrate our patriotic heritage. -----


4) http://www.greateryellowstone.org/news/op-eds/op-ed-nat-reso...
----- We call on Bush to open his eyes and see the wildlands he visits this week for what they truly are: not just a source of commodities to be extracted but an intrinsic part of **this nation's patriotic heritage** -- a symbol of our national vigor and freedom and an irreplaceable trust for our future. -----

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If it helps, I've done a quick translation of the whole phrase because I needed to see how the whole flowed together:

--- The latter has turned into a battleground for nationalistic competition, a challenge that sees the "Deutscher und Österreichischer Alpenverein" and the Italian "Società Alpinisti Tridentini" engaged in a sort of nationalistic colonisation of [or: in a nationalistic race to colonise/conquer...?] the Alpine peaks-Spitzen, which are then renamed accordingly, with appellations drawing on the respective nation's patriotic heritage. ---

Where "respective nation" means the nation that gets to "conquer" the peak. I left out a few repetitions. Anyway it's just a rough translation to see how the "heritage" phrase fits in there.