Microsoft Excel has many built-in features, but they can't expect to cover the waterfront. In the past, I've put together some tools that have been useful in displaying data as maps, and in extracting data from files. The image at left, for example, is a plot of part of the east coast of the US, with the Gulf Stream outlined. Excel makes it simple to do this kind of plot.
Here are some other (free) things I've found useful. I assume you already know enough about "extending" Excel to install them yourself.
- Coastline Extractor Not really an "Excel tool" per se, it's a database of coastline data for the world, in various scales. I downloaded the data for the image above from the database, then deleted many of the points to make the file size more manageable. The Gulf Stream data came from a separate source.
- GeoFunc.xla This is a very handy set of " functions that perform trigonometric calculations for plane and spherical geometry and a number of other related calculations." Compiled by Jeff Laake at the National Marine Mammal Laboratory.
- XY Chart Labeler This utility enables you to add labels to x-y data plots, and move them around in 1 point increments. The AppsPro site lists other free utilities as well.