many open tables in innodb

[Dean]

In the manual, it says:

"If you have many MyISAM or ISAM tables in a database directory, open, close, and create operations are slow. If you execute SELECT statements on many different tables, there is a little overhead when the table cache is full, because for every table that has to be opened, another must be closed. You can reduce this overhead by making the table cache larger. "

Does this apply at all to innodb? Specifically, does innodb care how many tables it has opened in memory, or does it only care about the total key/index size?

I am writing an application for geographical data, and I am able to to make tables both extremely large or extremely small. I am searching for keywords in these tables, but I only care about keywords that are about 0-40km (0-25miles) from a given latitude/longitude. Any recommendations, or do I just need to test for the optimal table size?

Thanks,
Dean Michael Gores