These other websites have information about Castlemartin:

Website Description
GENUKI: UK & Ireland Genealogy UK and Ireland Genealogy:The aim of GENUKI is to serve as a comprehensive "virtual reference library" of genealogical information that is of particular relevance to the UK & Ireland. It is organised so as to make it easy to find what information on what topics is available online related to given geographical localities (even down to parish level). It is a noncommercial service, provided by an ever-growing group of volunteers in cooperation with the Federation of Family History Societies.

Read what they say about Castlemartin
GeoNames The GeoNames geographical database is available for download free of charge under a creative commons attribution license. It contains over 10 million geographical names and consists of over 8 million unique features whereof 2.8 million populated places and 5.5 million alternate names. All features are categorized into one out of nine feature classes and further subcategorized into one out of 645 feature codes.

Read what they say about Castlemartin

These other websites provide geo-referenced information covering Castlemartin:

Geograph georeferenced photos "The Geograph British Isles project aims to collect geographically representative photographs and information for every square kilometre of Great Britain and Ireland."
GeoNames "The GeoNames geographical database covers all countries and contains over eight million placenames that are available for download free of charge."
National Library of Scotland On the National Library of Scotland's Map images website, you can access and view over a quarter of a million maps as high-resolution, colour, zoomable images. They are happy to supply printouts, digital images, and photocopies of their maps.
Open Street Map "OpenStreetMap provides map data for thousands of websites, mobile apps, and hardware devices. OSM is built by a community of mappers that contribute and maintain data about roads, trails, cafes, railway stations, and much more, all over the world."