Searching an area for something

Question

If you (or other people) are searching an area for something (in my case I'm searching for a number in a wide grid), and you get the searching area smaller.

What is the expression for that?

I'm not sure if I'm clear enough.

I googled and I got,

• "closing a search" : to stop looking
• "tightening a search" : I got nothing

So what should I use?

I'm going to use it like, ___ the search over a smaller area.

Answer 1

There are several closely related terms:

• Narrow the search is probably the expression you want, if you have already eliminated some areas after looking there and finding nothing. You are then going to look in the unsearched area, which is now smaller than before, with the expectation that you will find the goal there.
• Focus the search means that you are looking particularly hard in one area, for any reason. Maybe you are arbitrarily deciding to do an intensive search in one particular area first, based on just a suspicion. For example, if you are searching for a missing person, you might refocus the search somewhere based on eyewitness reports, even though you haven't ruled out the possibility of finding the person elsewhere.
• Restrict the search or Limit the search means to disregard part of the search space. For example, you might restrict a video search to high-definition videos only.
• Closing in on a target means that you are very close to knowing where to find what you are looking for, and are getting even closer.

Answer 2

You can say you are narrowing your search.

http://dictionary.reference.com/browse/narrow

14. to limit or restrict (often followed by down): to narrow an area of search; to narrow down a contest to three competitors.