Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities, including economic development, security and defense, scientific research, and environmental protection.
A nautical chart or hydrographic chart is a graphic representation of a sea region or water body and adjacent coasts or banks. Depending on the scale of the chart, it may show depths of water (bathymetry) and heights of land (topography), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, critical data such as Local Notices to Mariners are added to the on-demand chart files so that these charts are up to date at the time of printing.
Piloting or pilotage is the process of navigating on water or in the air using fixed points of reference on the sea or on land, usually with reference to a nautical chart or aeronautical chart to obtain a fix of the position of the vessel or aircraft with respect to a desired course or location. Horizontal fixes of position from known reference points may be obtained by sight or by radar. Vertical position may be obtained by depth sounder to determine depth of the water body below a vessel or by altimeter to determine an aircraft's altitude, from which its distance above the ground can be deduced. Piloting a vessel is usually practiced close to shore or on inland waterways. Pilotage of an aircraft is practiced under visual meteorological conditions for flight.
A bathymetric chart is a type of isarithmic map that depicts the submerged bathymetry and physiographic features of ocean and sea bottoms. Their primary purpose is to provide detailed depth contours of ocean topography as well as provide the size, shape and distribution of underwater features.
OpenStreetMap is a free, open geographic database updated and maintained by a community of volunteers via open collaboration. Contributors collect data from surveys, trace from aerial imagery and also import from other freely licensed geodata sources. OpenStreetMap is freely licensed under the Open Database License and as a result commonly used to make electronic maps, inform turn-by-turn navigation, assist in humanitarian aid and data visualisation. OpenStreetMap uses its own topology to store geographical features which can then be exported into other GIS file formats. The OpenStreetMap website itself is an online map, geodata search engine and editor.
An electronic navigational chart (ENC) is an official database created by a national hydrographic office for use with an Electronic Chart Display and Information System (ECDIS). ECDIS and ENCs are the primary means of electronic navigation on cargo ships. Charts can be used in navigation to provide an indication of location once a position is fixed and the charted depths can be used in under keel clearance calculations to ensure the ship is navigating in safe water.
Global Navigation Satellite System (GNSS) receivers, using the GPS, GLONASS, Galileo or BeiDou system, are used in many applications. The first systems were developed in the 20th century, mainly to help military personnel find their way, but location awareness soon found many civilian applications.
A satellite navigation device, satnav device or satellite navigation receiver is a user equipment that uses one or more of several global navigation satellite systems (GNSS) to calculate the device's geographical position and provide navigational advice. Depending on the software used, the satnav device may display the position on a map, as geographic coordinates, or may offer routing directions.
Reverse geocoding is the process of converting a location as described by geographic coordinates to a human-readable address or place name. It is the opposite of forward geocoding, hence the term reverse. Reverse geocoding permits the identification of nearby street addresses, places, and/or areal subdivisions such as neighbourhoods, county, state, or country. Combined with geocoding and routing services, reverse geocoding is a critical component of mobile location-based services and Enhanced 911 to convert a coordinate obtained by GPS to a readable street address which is easier to understand by the end user, but not necessarily with a better accuracy.
Google Maps Navigation is a mobile application developed by Google for the Android and iOS operating systems that later integrated into the Google Maps mobile app. The application uses an Internet connection to a GPS navigation system to provide turn-by-turn voice-guided instructions on how to arrive at a given destination. The application requires a connection to Internet data and normally uses a GPS satellite connection to determine its location. A user can enter a destination into the application, which will plot a path to it. The app displays the user's progress along the route and issues instructions for each turn.
Sygic is a Slovak company of global automotive navigation systems for mobile phones and tablets. The company was founded in 2004 and is headquartered in Bratislava, Slovakia. It became the first company to offer navigation for iPhone and second for Android. In 2015 Sygic reached milestone of 100 million downloads of its navigation app.
Turn-by-turn navigation is a feature of some satellite navigation devices where directions for a selected route are continually presented to the user in the form of spoken or visual instructions. The system keeps the user up-to-date about the best route to the destination, and is often updated according to changing factors such as traffic and road conditions. Turn-by-turn systems typically use an electronic voice to inform the user whether to turn left or right, the street name, and the distance to the next turn.
OsmAnd is a map and navigation app for Android and iOS. It uses the OpenStreetMap (OSM) map database for its primary displays, but is an independent app not endorsed by the OpenStreetMap Foundation. It is available in both free and paid versions; the latter unlocks the download limit for offline maps and provides access to Wikipedia points of interest (POIs) and their descriptions from within the app. Map data can be stored on the device for offline use. Using the device's GPS capabilities, OsmAnd offers routing, with visual and voice guidance, for car, bike, and pedestrian. All of the main functionalities work both online and offline.
Apple Maps is a web mapping service developed by Apple Inc. As the default map system of iOS, iPadOS, macOS, and watchOS, it provides directions and estimated times of arrival for driving, walking, cycling, and public transportation navigation. A "Flyover" mode shows certain urban centers and other places of interest in a 3D landscape composed of models of buildings and structures.
A moving map display (MMD) / projected map display (PMD) is a type of navigation system output that, instead of numerically displaying the current geographical coordinates determined by the navigation unit or an heading and distance indication of a certain waypoint, displays the unit's current location at the center of a map. As the unit moves around and new coordinates are therefore determined, the map moves to keep its position at the center of the display.
This article contains a list with gratis satellite navigation software for a range of devices. Some of the free software mentioned here does not have detailed maps or the ability to follow streets or type in street names. However, in many cases, it is also that which makes the program free, avoid the need of an Internet connection, and make it very lightweight. Very basic programs like this may not be suitable for road navigation in cars, but serve their purpose for navigation while walking or trekking, and for use at sea. To determine the GPS coordinates of a destination, one can use sites such as GPScoordinates.eu and GPS visualizer.
Here WeGo is a web mapping and satellite navigation software, operated by HERE Technologies and available on the Web and mobile platforms. It is based on HERE's location data platform, providing its in-house data, which includes satellite views, traffic data, and other location services. Maps are updated every two or three months.
Locus Map is a multi-functional Android navigation app. Primarily it is designed and used for leisure time outdoor activities like hiking, biking, or geocaching. The app is also used by professionals e.g. by S&R teams or for collecting geospatial data.
Yandex Maps is a Russian web mapping service developed by Yandex. The service provides detailed maps of the whole world, directions and estimated times of arrival for driving, walking, cycling, kick scooter, and public transportation navigation. It includes a search, information about traffic jams, routing and street panoramas. The service was launched in 2004.
Organic Maps is a community-developed, privacy-focused and offline navigation app. This app has the main features of no location tracking and no data collection. The map data is downloaded to the phone so search, routing, and navigation can operate without a cell phone signal, ideal for travel to locations with poor connections. Organic Maps uses the crowdsourced map data from OpenStreetMap. The app is free and open-source software, with priority for community development and collaboration.
