Maps

Easy GPS
Free GPS map site. Provides more advanced version with commercial software.

Google Maps
An easy to access source for the novice and advanced outdoorsperson.

TopoZone
TopoZone is the Web's center for recreational and professional topographic map users.

MAPTECH Map Server
Maptech MapServer Maps and Charts: View FREE USGS Topo Maps, NOAA Nautical Charts, Aerial Photos. GPS Navigation Software.

TerraServer
TerraServer contains 3.3 tera-bytes of high resolution USGS aerial imagery and USGS topographic maps.

Purchase map from USGS
A quick and easy way to find and order detailed USGS paper maps.

Texas Mapping
Texas Water Development Board Map Site

Maps on us
Maps and Trip Directions

MapQuest
Maps and Trip Directions

Map Tools
MapTools provides GPS users with the tools and knowledge to fully utilize geographic coordinates. MapTools produces grids, corner rulers, roamers, and rulers to assist with plotting or measuring positions on many different scales of maps.

Global Positioning System

GPS
Global Positioning System satellites transmit signals to equipment on the ground. When the receiver estimates the distance to at least four GPS satellites, it can calculate its position in three dimentions.

GPS World
Commercial Magazine discussing GPS technologies

Garmin
Manafacturer of Global Positioning System (GPS) technology and electronics.

Magellan
Manafacturer of Global Positioning System (GPS) technology and electronics.

Trimble
Provides a tutorial on GPS use.

The Aerospace Corporation
Provides a GPS primer.

GPSy
This is a page of links containing information about the Global Positioning System (GPS) and handheld GPS units.

Water

Water Data
The U.S. Geological Survey has the principal responsibility within the Federal Government to provide the hydrologic information.

Stream real time data (Texas)
USGS data for Texas

www.saltwatertides.com
Source for tide, moon, and sun predictions for the Gulf Coast, US East Coast and US West Coast.

Daily Tide and Current Predictions
Tide and current predictions are available for thousands of locations in North and Central America as available from NOAA and CHS.

Regions with Tide Predictions
The listed regions have tides calculated automatically for many sites.

The National Oceanographic Data Center
Archives and provides public access to global oceanographic and coastal data, products, and information

National Oceanic and Atmospheric Administration
Provides a vast variety of information including weather data.