在玩户外的人中，GPS的拥有量开始增加，什么型号的GPS适合户外使用？我在买GPS之前看过不少资料，可以参考一下。
GPS information是一个很值得看的站点，几大GPS厂家的设备信息、GPS相关软件、使用心得等等资料非常齐全。
该网站里面一篇文章Important features for a hiking GPS介绍了什么GPS适合于hiking使用。
摘录部分出来：
Below are my “essential hiking feature list” of GPS receiver features.
(I omitted features that are present in ALL receivers.)
12 channel parallel receiver system: Needed for best reception in difficult terrain and tree cover.
WaterProofness: Unit should be rated submersible to protect it from getting wet.
Long battery life: Keeps you from having to carry so many batteries.
Built in Maps: Not absolutely essential, but big help in orientation and estimating distance to nearest roads.
Route capability: Twenty Route capability is pretty standard. Make sure you get one with at least 20 routes.
Waypoints: 500+ user entered waypoints are pretty standard. Make sure you get one of these.
Multiple Datum capability is pretty standard: Make sure all the datums you will want to use are included in the GPS you select.
Fit nicely in your pocket and lightweight: This is a very personal thing, but you should consider it when you are thinking about hauling a unit around in the wilderness.
Bearing to next waypoint: Almost universal, but essential to hiking use.
Screen Size and your ability to read it are important especially if you have problems with viewing fine detail.
Not ABSOLUTELY essential features, but nice to have.
“Map” screen (as opposed to just a numerical lon/lat position fix): Makes it much easier to see where you are relative to reference waypoints.
Rotatable screen: Garmin makes a couple of units capable of rotating the screen vertical (handheld use) or horizontal (car dash use). These are not the handiest for pocket use, but lots of people like this compromise for joint hiking/car use.
UTM readout may be a consideration for some. This feature is available on a limited selection of consumer GPS receivers.
Topo Maps uploaded into your GPS: The Garmin USA Topo CD maps contain contour lines and small stream data very helpful in navigating in off-road territory. Magellan has a new TOPO map offering for the M330 available late Summer 2001.
For use under heavy tree cover or difficult (multipath) terrain conditions, an external amplified antenna will generally be helpful.
A minimum of 8 megs of map memory is recommended on a mapping GPS though you can “get by” with 1.4 megs or so.
中文站点方面，绿野论坛的通讯版估计是目前集中了最多户外GPS玩家的地方。
这是绿野网友晨峰归纳的GPS选购原则：
户外用的GPS有特殊性，我尝试列了几点，从经验上觉得最重要到次重要的。不考虑价钱的因素。
1、防水和Rocky Panel功能。（不能太娇嫩，最好可以达到军用标准）
2、电源（耗电量小，使用时间相对长，低温条件下能工作稳定）
3、考虑丛林条件的天线设计和恶劣条件下的信号捕捉能力。
4、自动记录点的时间间距可调，Trace Back功能（完整的记录和大雾条件下使用）
5、重量、体积适中。
6、大屏幕或彩屏，自制矢量化地图。
inc的GPS zone虽然资料不算很多，但好像是目前比较好的关于GPS的中文个人站点了。
我自己就没有仔细归纳过，根据使用经验来说，想到几点：
- 防水性、坚固性很重要，不能带个娇贵的东西到户外的恶劣环境
- 屏幕要有足够的分辨率(象素)，并且map页面zoom到最大的时候应该要能分辨出10米以内距离
- track的容量越大越好，track记录间隔可设置，能够记录尽量长的航迹。waypoint、route的容量我反而觉得不是很重要，一般都够用(前提是有数据线，平常数据都保存在电脑上)
- 数据线很有用，可以在电脑上保存、整理资料数据。
- 卫星信号接收能力强，特别是树林中的接收能力很重要
- 如果仅仅是户外活动使用，不开车，那么地图功能是毫无用处的。
有机会最好还是在购买前先试用一下，对于操作使用有感性认识，看看用起来顺不顺手，单单比较性能指标是不够的。