Should an older question "Are there any GIS component that can be used for developing GIS applications for Android phones?" with several answers be closed as a duplicate, when an new question is created that are presumed to be more clear or better "Is there an comparison of the various mapping libraries for Android?" are added?
Having reviewed the two Q&As that you cite, my preferred approach on this would have been for:
- the earlier Question to have been edited by the later asker to improve it (no one expects a Question written 3 years ago to be perfect for today); and
- the later Answer to have been added to those on the earlier Question where I would expect to see it "float" via voting quickly to or near the top
However, the earlier question may only have been seen by the later asker after that later Q&A had considerable time invested in writing it, so an expedient then may have been to just make the earlier question a duplicate.
My voting pattern on this will be to try and re-open the earlier question, try to close the later Question as a duplicate of the earlier one, hope the best Answer (which is on the later Question) gets added to the earlier Question, upvote the best Answer(s) on the earlier Question, and downvote/edit/flag any there that look "terrible".
If it pans out this way, then I hope any edits made to the earlier Question will be considered carefully and objectively before any inclination to roll them back is exercised.
A word of advice to the asker is that in light of the other Answer, this is looking more and more like a case where some "gardening" of your Question (and the Answers), in the period since it was first asked, may well have avoided the later Question being inadvertently (re-)asked. This Google+ Hangout video for Agile India entitled Good Stack Overflow Citizen by Jeff Atwood talks about "gardening" your Question(s), and offers much other sage advice. It is not too late to do some "gardening" of the original Question now.
While looking at the situation it should be noted that the old question is over 3 years old, while the 'new' question is over 1 year old; I found the older question just last week while I was searching for something else.
I have always maintained that
When marking a question as duplicate, the Quality of Question and Answers is far more important, than the age of the Question.
(Notice that I said quality, and not quantity)
In this case, I feel that the quality of most answers on the old question is not up to the mark. Look at the posts from the view of an developer who comes to it from Google. The person searched for "GIS component that can be used for developing GIS applications for Android", since he wants to use such an component in his own App.
Now he reads the various Answers, and this is what his reaction will be:
- The accepted Answer about gvSIG Mini. How would a developer use it as a component in his own application? That information is not available on the linked site. Show me one Application that uses gvSIG Mini to show maps.
- Geopaparazzi . Ok here is a $14 app on the Play store. Good for the Creator! But again how do I use it as a component in my Application?
- Nutiteq Android SDK - At last something useful.
- An general answer about Flash, Silverlight and HTML5- How is that going to help me?
- ExtMap Touch- There is no information about using it in an Android Application.
If you look at it from this point of view, there is basically just one answer which is useful to future users. Compared to this, my answer on the new question has much more information, and talks about many more libraries.
Of course this is very much my opinion, and I stated it as such when I first voted to close the question. (It's very much possible that others might disagree with my opinion; That's why it is called an opinion)
If I had found your question when I was searching for this information one year back, yes I would have posted my Answer on it. Unfortunately I didn't find it, and hence had to post a new question, and then ultimately after my research, I shared the results of my research with the community in an answer on the new question.
It's up to us, the community to decide which one they feel better serves as a canonical resource, and I have no problem going along with the wishes of the community.