Most GPS navigators come with their own set of maps. If the devices are compatible, you are able to use third party maps, too. The problem is that these maps have POIs, or points of interest, marked on the maps that try to cater to a mixed set of users. These maps are likely to have different things that interest a variety of users.. Thus, typically, these maps have POIs marked on them that tend to cover a common denominator. Gas stations, restaurants, rest areas, and motels are usually the common POIs provided on such maps.
Custom POI Files
So, if you are interested in a specific set(s), of POI then what are the available options? These are typically third party providers who supply such files. Some files are claimed to hold more than a million POI data in them. The websites that sell these POI files usually have their own products, of course. Most often they also have a forum where people can and do contribute special interest POI files. A couple of sites that have been picked from top search results are POI Factory and POI Directory. These provide a source of a rich variety of POI data. These are illustrated to indicate the kind of products that are usually available. The forums available at such sites provide a means to find any esoteric needs you may have and the special POI data that is not commonly available.
The POI Factory has a rating system based on popularity, and it lists these categories. Recent categories are WalMart, Sam’s Clubs, and WalMart Supercenters in the US and Canada, rest areas, and places to visit in the US. One category that is rising fast is the locations of Rite Aid Pharmacy. Some fifty odd categories are listed on a wide range of topics. A sampling of the categories will give you an idea of how wide a range these cover. The categories include airports/aviation, astronomy, ATM/banks, beer/breweries/distilleries, boating, camping, grocery/convenience stores, health clubs/gyms, hospitals/ERs, libraries, and so on. What is interesting is there are several files in each category, sometimes in the hundreds. Categories of POI files also include such very niche interest areas as where red light or speeding cameras are located.
Categories by Compatibility
While the above categorization is organized by interest areas, another possibility is by device type. What that means is organization by file format compatibility. Maps used by different GPS devices are of different types. They may even be different between products from the same manufacturer, too. These maps need the POI data in a certain format. So, this style of categorization is by specifying that the POI data is compatible with a specific device type. This kind of offerings is shown at the second site the POI Directory. The POI files available are indicated by device category and a wide range of devices types indicated at the site. Garmin, Magellan, Tom Tom are from POI Directory.
Compatibility and File Type
Once you have the POI files, they will need to be integrated with the maps you use on your particular device. To help facilitate the import, the POI data files will have to be in a specific format. Typically CSV or the comma separated value format is the most common. With Garmin, Tom Tom, and Magellan being popular devices, POI data files are available that can be imported directly to the maps used by these devices. Sometimes you will need to convert the format, and data conversion software pieces have started becoming available.