Please select departure and arrival city to caculate flight time and distance between them. at a point that…. 691. DESCRIPTION. 17 * sqrt (eye height in feet) = (distance in miles) While wikihow says. In the Arctic, sea ice is a way of life—from the animals that depend on it for breeding, shelter, and food, to the people who rely on hunting for their livelihoods. ) or most any crossword answer. There are particular seas and the sea. You can calculate the length of a path, running route, fence, border, or the perimeter of any object that. 0 • Revision Number: 0a2c5103Driving distances between two cities. Meters per second. Of course, we will also deliver the rental boat to your house if you want to start from there. A. The top solutions are determined by popularity, ratings and frequency of searches. 852 kilometres (km) one nautical mile (nmi) = 1. Red Sea, narrow strip of water extending southeastward from Suez, Egypt, for about 1,200 miles (1,930 km) to the Bab el-Mandeb Strait, which connects with the Gulf of Aden and thence with the Arabian Sea. Discover ocean depths, wind speed,. 15 miles per hour or 1. So the surface of the. To convert nautical miles to miles: Miles = Nautical Miles * 1. , helicopters, airplanes). Whether you’re traveling alone or with others, find a ride option that fits your needs and budget. A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Search for popular ships globally. Popular distances from Seattle (SEA) Distance from Seattle to Paris (Seattle–Tacoma International Airport – Paris Charles de Gaulle Airport) is 5016 miles / 8073 kilometers / 4359 nautical miles. Rate and speed are similar since they both represent some distance per unit time like miles per hour or kilometers per hour. Preview of Nautical Sea Distance Calculator Result. In the bottom left, select Mouse Navigation. Calculate the distance, fuel consumption, and cost of your next boating trip. It’s a crucial measure for safe and accurate navigation on the water. For example, if our eye is 5 feet above sea level, then the horizon distance is about 1:22459 p 5 = 2:738 miles away. DESCRIPTION. Share. Searates provides Online Tool for Distance Calculation & Shipping Rates Between Air & Sea Ports. Get estimated flight time by choosing an aircraft type or entering the cruising speed. Speed is (select units before calculating):The CERDI-seadistance database. Copyright © 2023 by SEA-DISTANCES. More than 4000 sea ports. Minutes. More than 4. You can use this distance calculator to find out the distance between two or more points anywhere on the earth. [6] The territorial sea is sovereign territory, although foreign ships (military and civilian) are. North Atlantic Ocean » 6. 1 billion distance data with (S)ECA, Weather Forecast, Piracy Alert and many other powerful functions. How to choose Departure and Arrival points on the map with calculator's target buttons. Travelmath helps you find driving distances based on actual directions for your road trip. Then draw a route by clicking on the starting point, followed by all the subsequent points you want to measure. Antipode: -47. Distance calculator finds the distance between cities or places and shows the distance in miles and kilometers. g. Get point to point, port to point, and port to port sea routes and sea distances. Or if you're taking an international flight and you want to plan your arrival time, check the flight time between airports. The distance in miles and kilometers will display for the straight line or flight mileage along with the distance it would take to get there in a car. e. You can plan your sailing journey down to the last detail with our interactive distance calculator. More than 4000 sea ports. This calculator converts various nautical measurement units. The driving distance from Seattle (SEA) to Dallas (DFW) is 2084 miles / 3354 kilometers, and travel time by car is about 36 hours 59 minutes. GPH = (0. You can also book a hotel near the airport. The Get-Routes Service: Provides the means for getting a route between up to 16 points at sea (with a single call). It is developed under consideration for user-friendly UX & UI to enhance efficiency of your daily work. e. Check Shipping Vessels Schedules By Routing, By Port, By Vessel, or By Carrier. 60934 kilometers. A nautical knot is a unit of speed equal to one nautical mile per hour (1 knot = 1. How far is it from Southend-on-sea to the South Pole? From Southend-on-sea to the South Pole, it is 9,780. It will also display local time in each of the locations. g. Nautical mile speed, commonly referred to as “knots,” is a unit of speed used in maritime and aviation contexts. e CO2 equivalent emissions) statistics of a shipment for a given carrier, and for a given port pair. To find speed, time or distance, enter a value in two of the three fields, and the third will be calculated for you. The distance between Seattle (Seattle–Tacoma International Airport) and Los Angeles (Los Angeles International Airport) is 954 miles / 1535 kilometers / 829 nautical miles. Answer: Space is 62 vertical miles away. Saint Helena. C. The CERDI-SeaDistance database contains bilateral maritime distances between 227 countries and territories. Calculates the speed in knots and the distance in nautical miles at shipping. To find speed, time or distance, enter a value in two of the three fields, and the third will be calculated for you. The Defense Table of Official Distances (DTOD) is the official source for worldwide distance information used by the Department of Defense (DoD). The distance between Santa Ana (Orange County John Wayne Airport) and Seattle (Seattle–Tacoma International Airport) is 978 miles / 1574 kilometers / 850 nautical miles. Time Zones Map. 2. Saint Barthelemy. See also a map, estimated flight duration, carbon dioxide emissions and the time difference between Seattle and Doha. The Dataloy Distance Table is highly acclaimed for its extensiveness and accuracy. The relevant port (s) for countries with access to the sea is defined as the coastal cell of a country that contains the highest number of shipping lines, and. 06 km) How far is it from SEA to the South Pole? From SEA to the South Pole, it is 9,496. 60934 kilometers. Schedules sourced directly from more than 230 operators. Sea Distance & Time API. You can also book a hotel near the airport. More information from the unit converter. The distance between Seattle (Seattle–Tacoma International Airport) and Phoenix (Phoenix Sky Harbor International Airport) is 1107 miles / 1781 kilometers / 962 nautical miles. For artists, writers, gamemasters, musicians, programmers, philosophers and scientists alike! The creation of new worlds and new universes has long been a key element of speculative fiction, from the fantasy works of Tolkien and Le Guin, to the science-fiction universes of Delany and Asimov, to the tabletop realm of Gygax and Barker, and beyond. Vol. Downloadable! We describe the publicly available CERDI-seadistance database, which contains bilateral maritime distances between 227 countries and territories. Distance facts. But this herd has been lumbering its way across China for more than a year now. This distance and driving directions will also be displayed on an interactive map labeled as Distance Map and Driving Directions US. distance definition: 1. However, winds, currents, river discharges, and variations in gravity and temperature prevent the sea surface from being truly level. It’s a crucial measure for safe and accurate navigation on the water. To find the speed of a vessel on a measured nautical mile in a given number of minutes and seconds of time, enter the time in total seconds (i. More than 4000 sea ports. 5 * eye height in feet) = (distance in miles) They can't both be right, because the sqrt (1. the amount of space between two places: 2. Please provide a description of the route (e. The CERDI-seadistance database provides a matrix of bilateral sea distances for 227 countries and territories. In this raster we have to indicate the resolution, in our case it is of 5000m, the projection and the extension of the raster. It generates point-to-point distances and routes for origin/destination pairs of locations. Because of the variable road conditions, travel times can often take longer than you expect. Time Zones Map. Roger Barrier, founder of Preach It, Teach It, is a well-known author and sought-after conference speaker. 449,57. Sea Distances. 15078 mph. Instrument Accuracy. Minimum per segment: Ticket price (in dollars): Note: These air mile distances are approximate and are based on data provided by various outside sources. Regions . 2 PM + 11 hours 15 minutes = 1:15 AM. Similar to the speed and distance measurement on land, the nautical mile and knot explain the movement of a vessel at sea. All Rights Reserved. Fuel consumption will be decreased at cruising speeds. This module is available as an addition to a Sea-web Ships or a Sea-web Ports subscription. To check our calculations, we can work out an “exact” formula and compare. 15078. Are there APIs or datasets that would allow me to calculate the shortest over-water distance between two points, given the points' latitude and longitude?Distance Calculator. To remove a point, click it. View vessel details and ship photos. A yellow pin marker will be placed on the selected vessel or point on the Live Map. C. r"],"stylingDirectives":null,"csv":null,"csvError":null,"dependabotInfo":{"showConfigurationBanner":false,"configFilePath":null,"networkDependabotPath":"/vpanagos. Save and share the routes. Please select departure and arrival ports from the dropdowns. Often customers are given a very rough estimate of their delivery. The driving distance from Seattle (SEA) to Phoenix (PHX) is 1420 miles / 2286 kilometers, and travel time by car is about 26 hours 33 minutes. The CERDI-seadistance database. DTOD provides vehicular land distances for all DoD personal property, all DoD freight, and PCS/TDY travel needs. [Note: The distance between cities in Canada distance chart below is straight line distance (may be called as flying or air distance) between the two locations in Canada calculated based on. Find clues for Sea distances (2 wds. Maritime routes are structured according to the type of commercial service they support, which comes in three main categories: Port-to-port. Conversion Formula. 000. The driving distance from Seattle (SEA) to Los Angeles (LAX) is 1127 miles / 1814 kilometers, and travel time by car is about 21 hours 18 minutes. Date format is yyyy/MM/dd. 14 mi (6,115. One knot is equivalent to one nautical mile per hour, which is approximately 1. . MarineTraffic Online Services enable you to monitor, review, analyse and plan shipping operations. Preview of Nautical Sea Distance Calculator Result. Here are two standard methods: Vincenty's formula (applied above) 2677. Kilometers per hour. MM) or degrees, minutes, and decimal seconds (DD:MM:SS. On Rappahannock, we would normally use. This Advanced Distance Calculator is the successor to the Distance Calculator. Mileage Calculator: Calculate the mileage of a flight between airports or the mileage of a car between addresses. Tip: To move a point or path, click and drag it. Contribute to vpanagos/seadistance development by creating an account on GitHub. EuroVelo 6 – Atlantic–Black Sea is one of the most popular EuroVelo routes, and it’s little wonder why. You can get the distance between cities, airports, states, countries, or zip codes to figure out the best route to travel to your destination. 486 kilometers. Please log in with your VesselFinder account and refresh this page. Contact the USTRANSCOM Service Desk at DSN (322) 817-6432/Com (618) 817-6432 or email TRANSCOM Service Desk. Boat's waterline length. To create a path to measure, click anywhere on the map. As you can share your location, it will let you know easily how far you are in a straight line from any point of interest. Mediterranean Sea » 3. org show that sea-distances. A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. Kilometers (km): is the unit of length equal to 1000 meters or 0. Cat. We describe the publicly available CERDI-seadistance database, which contains bilateral maritime distances between 227 countries and territories. Miles (mi): is also the unit of length which is rarely used and is equal to 1. 6 or 2. We offer freight rates from the world's leading logistics providers, shipping lines and other vendors to destinations around the world. What sets this tool apart is the fact that the routes are based on actual voyage data recorded by MarineTraffic, as opposed to algorithmic routing that does not respect maritime traffic restrictions, such as Traffic Separation Schemes, safe waterways, turning. Then click Done when you're done editing and go to the Documents tab to merge or split the file. The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convention. You can use the equivalent formula d = rt which means. You can easily calculate/measure the distance between a vessel and any other Waypoint as defined by you. net is a maritime website monitoring ship traffic in 14 different types of geo regions like Seas, Straits, Canals, Sounds, Reefs etc. Follow. Malaysia Driving Distance Calculator to calculate driving distance between cities, towns or villages in Malaysia and Mileage Calculator, Distance Chart, Distance Map. SEA DISTANCE CALCULATOR Map of ports all around the world, Enter two ports, choose speed and find out how long it will take. Plan your journey. MarineTraffic Live Ships Map. Minimum miles. Distances Between United States Ports is published by the Office of Coast Survey, National Ocean Service (NOS), National Oceanic and Atmospheric Administration (NOAA), pursuant to the Act of 6 August 1947 (33 U. The Red Sea is the world’s northernmost tropical sea and is also one of the most heavily traveled waterways. Land freight: 13-17 days. Just follow these 3 simple steps: Type in your starting point, e. The distance between Seattle (Seattle–Tacoma International Airport) and Nashville (Nashville International Airport) is 1978 miles / 3183 kilometers / 1719 nautical miles. Where the "island" column is blank on departure, it's a repeat of the row above. The distances in the tables have been calculated using routes which have been plotted by experienced Master Mariners and updated by Marine Navigators. Speed measurement units. About Ship Radio Stations The GMDSS is an internationally recognized distress and radio communication safety system that has been in place for several decades. A Nautical Mile is 1/60th of a degree or one minute of latitude. In its desire to test the long- range capabilities of the airplane, the Air Service decided to fly a Glenn Martin bomber completely around the periphery of the U. Bus, line 256 bus • 2h 4m. 06 km) in the north. It is important to estimate transit times for various routes to any location in the world for both consignees and shippers. The Alberta Motor. Find locations of ports and ships using the near Real Time ships map. Container Lines ALL LINES MAERSK (332) CMA CGM (253) MSC (615) EVERGREEN (171) COSCO (129) APL (48) ONE (65) NYK (31) HAPAG LLOYD (107)Red Sea. Population connectivity refers to the exchange of individuals among populations: it affects gene flow, regulates population size and function, and mitigates recovery from natural or anthropogenic disturbances. One kilometer (km) = 0. Find the shortest route, ETA, days in sea, bunker ports along the route and estimated bunker. the time in an hour, minute, and second format. Export the distance as a raster. ) crossword clue, 5 letters. The United Nations Convention on the Law of the Sea ( UNCLOS ), also called the Law of the Sea Convention or the Law of the Sea Treaty, is an international agreement that establishes a legal framework for all marine and maritime activities. It takes a lot of energy to overcome gravity for that distance and gain the speed required to stay in orbit (approximately 17,500 miles per hour) once you've arrived. Solution: Formula: km / 1. SEA DISTANCES / PORT DISTANCES - online tool for calculation distances between sea ports. We have also included a directory of the top sites for driving directions, and maps. 15078 mph. The distance between the points will then be displayed. 96m sq km on 10 September and had fallen away since then. port distance tables. The famous sections along the Loire and the Danube Rivers are known to cycle tourists around the. Regions . buffer of a point, "as. Speed = Distance/Time. 000 distances. To reduce the number of listings needed, junction points along major routes are used to consolidate routes. Input them in the haversine distance formula: d = 2R × sin⁻¹ (√ [sin² ( (θ₂ - θ₁)/2) + cosθ₁ × cosθ₂ ×. Golfo De Panamá Gulf » 9. Regions . 2 = 120/7. A nautical mile is a unit of measurement used on water by sailors and/or navigators in shipping and aviation. To add another point, click anywhere on the map. The principle of internet banner advertising is based on how to attract the attention of the web viewers. While ticket prices remain undisclosed, passengers will be entitled to carry up to 40 kg of luggage without additional charges. Air distance (also called great circle or orthodrome) is also drawn on the distance map below. CO2 service provides CO2e emissions (i. We aim at helping shippers, BCOs, forwarders and carriers identify the greener routes to reduce their transport carbon footprint, all modes. MAP YOUR ROUTE. Miles (mi): is also the unit of length which is rarely used and is equal to 1. Whether you need information for a vessel, a port or at the global level, there’s a service to match your need. port distances, port distances table, port distances software, international port distances, mediterranean port distances, port distance by sea, shipping distances by sea, port distances calculator, port distances. ^top. SEA DISTANCES / PORT DISTANCES - online tool for calculation distances between sea ports. Why it Matters. We return the shortest route sailed considering traffic separation schemes, SECA/ECA zones, piracy zones, canals and port entries. The VMS API is designed to connect Dataloy VMS to the best in breed solutions for the maritime industry, helping you expand your product lines, increase the pace of innovation, and cut costs and time for integration. ORG All Rights Reserved. As modern tracking technology follows animals over ever-longer distances and durations, the last decade has revealed the largest daily migration and the. Total sail area square. 0. One km is equal to one thousand of meters (British spelling: metre), which is the current SI base unit of length. 169 miles. 000. While this journey planner tool gives distances in New Zealand, all times are approximate and do not allow time for stops, windy roads, heavy traffic or the impact of weather conditions. Includes air line, route, centre, route planner, flight route and interactive map. The results were similar to those presented here. ORG All Rights Reserved. The relevant port (s) for countries with access to the sea is defined as the coastal cell of a country that contains the highest number of shipping lines, and each. Vancouver to Toronto distance (YVR–YYZ) Anchorage to Seattle distance (ANC–SEA) London to Sydney distance (LHR–SYD) Air Miles Calculator helps you calculate how many miles it is from one airport to another and provides a map, estimated flight time, time difference between cities, and estimated CO2 emissions. Trans-Indian ocean traffic is dominantly intermediary traffic between Pacific Asia and Europe, implying a series of clearly defined routes between the Strait of Malacca and Bab el-Mandab. You can have a stress-free ride knowing that. Boats with deeper draft may have to select longer routes to avoid shallows. 916 and longitude: -122. have? With crossword-solver. First off, you can use Google Maps, including its satellite view, to take a look at an area you plan to be boating. e. Calculator will immediately calculate with selected distance unit. Derived from an ancient Celtic unit and adopted by the Romans as the leuga, the league became a common unit of measurement throughout western Europe. McDistance is a mobile edition for the voyage calculation and voyage estimation application which synchronizes budget records with the desktop edition. Conversions. 72. Sea distances, terrestrial and satellite AIS data, weather data, forecasts and more from Aquaplot and trusted 3rd parties. Level 4: Skybridge to ground transportation and car parking. v. We'll call θ and φ to their respective latitude and longitude components. This is a daily measure of change and variability in the length and incidence of Antarctic coastline lacking any protective sea-ice buffer offshore. 62137 miles. Because the ocean is one continuous body of water, its surface tends to seek the same level throughout the world. Driving directions and travel distance calculation for. You can also use this nautical mile calculator to calculate the traveled distance based on vessel speed and. 15 statute mph. Beware of the fact that maps can distort distances. Result page displays distance in miles, kilometers and nautical miles along with an interactive map showing travel direction. British imperial control, wars, Jewish settlements and Israeli occupation have combined to substantially shrink the Palestinian people’s land area. Distance and route computation. Our free online flight time and distance calculator can be used as a flying route and fuel planner for any round trip, multi-stop, or one-way flight. The relevant port(s) for countries with access to the sea is defined as the coastal cell of a country that contains the highest number of shipping lines, and each landlocked country is associated. PUGET SOUND is a maritime region of type sounds located geographically at the following coordinates: latitude: 47. Seametrix’ s weather module is based on the Global Forecast System (GFS) and consists of two different functionalities: – The map’s on/off layering which offers you an up to 3 days’ forecast (with full global. Web Applications. To find the speed of a vessel on a measured nautical mile in a given number of minutes and seconds of time, enter the time in total seconds (i. More than 4000 sea ports. Get estimated flight time by choosing an aircraft type or entering the cruising speed. This calculator converts various nautical measurement units. Typically these are based upon following transportation routes such as public transit, roadways, or foot paths rather than using a simple circle (a. Track Container Shipment and stay informed for Container Ships' Schedules. Boats with deeper draft may have to select longer routes to avoid shallows. [2] [3] Historically, it was defined as the meridian arc length corresponding to one minute ( 1 60 of a degree). Buzzing, hovering, landing, taking off, and taxiing near. The relevant port(s) for countries with access to the sea is defined as the coastal region of a country which contains the highest number of shipping lines (landlocked countries are linked to the foreign port with the shortest road. 300-hp Gasoline Engine Example. Where do I get to when I dig a hole in SEA through the centre of the earth? Port to Port Sea Distance Calculator. This method uses the observation that the average distance between the left and right eye of an adult is about 6. Ship Types . The calculation used for determining the distance to the horizon takes into account variables such as vision, nautical miles, and the eyes. The function VI03 -Port Distances and Routes will calculate distances between ports (simple response) and even provide a track (extended response). Accurate routes and sea distances are a key criteria to improve decision making. Request a ride up to 90 days before your trip, at any time and on any day of the year. If you like to plan ahead, consider scheduling a ride to Newbiggin-by-the-Sea in advance. Log In Calculate the total nautical distance of your sea voyage with ease. Search the MarineTraffic ships database of more than 550000 active and decommissioned vessels. e. By plugging in your specific. The service is provided as a REST API service, using JSON format for the returned values. Alboran Sea » 4. Straits Canals Gulfs Bays Seas Oceans Rivers Lakes Sounds Fjords Reefs Lagoons Capes. As dimension for the speed, knots (kn) is used, one knot is one nautical mile per hour. Speed = 45 mph. You can also find a conversion table and the central positions of each port in this publication. Edit routes to reflect seasonal constraints and user-specific requirements. Km to nautical miles conversion example. 45 mi (15,283. You can also find a conversion table and the central positions of each port in this publication. If you like to plan ahead, consider scheduling a ride to Southend-on-Sea in advance. Simple, powerful and effective tools tailored to your needs. Canada Distance Chart (Distance Table): For your quick reference, below is a Distance Chart or Distance Table of distances between some of the major cities in Canada. net monitors 9 of the major sounds around the world. 449,57. What sets this tool apart is the fact that the routes are based on actual voyage data recorded by MarineTraffic, as opposed to algorithmic routing that does not respect maritime traffic restrictions, such as Traffic Separation Schemes, safe waterways, turning points etc. Buzzing, hovering, landing, taking off, and taxiing near marine mammals on land or in the water is. Check the list of other websites hosted by JSC "ISPsystem" . Sea-web is the ultimate maritime reference tool, with more than 600 data fields on over 220,000 ships of 100 GT and above. Since she made it into law, the mile has been known officially as the “ statute mile . from a place that is not near: 3. We describe the publicly available CERDI-seadistance database, which contains bilateral maritime distances between 227 countries and territories. Rhumbline & Great-Circle navigation methods are. Here are the basic conversion formulas for nautical miles: To convert nautical miles to kilometers: Kilometers = Nautical Miles * 1. When you ride with Uber on your next trip from Takeley to Leigh-on-Sea, you’ve got choices. In this raster we have to indicate the resolution, in our case it is of 5000m, the projection and the extension of the raster. 73 km) How far is Mediterranean-sea from the North Pole? Mediterranean-sea is located 3,800. The vessel designated for this ferry service has been named Cheriyapani. The driving distance from Seattle (SEA) to Los Angeles (LAX) is 1127 miles / 1814 kilometers, and travel time by car is about 21 hours 18 minutes. 14 mi (6,115. Click your route to navigate around the map - it will add up the distance as you go. Click in the large textfield above to enter all the airports of your flight route! Use Great Circle Mapper to calculate the distance and flight duration. If you are traveling to different cities and want to calculate the distance between cities, you can convert the city name to gps coordinates and then use the distance calculator or just use the distance between cities tool. Involves a more or less regular service between two ports, often moving back and forth with unidirectional freight flows involving empty backhauls. , M. nautical miles x 1. 1. The Distance Calculator can find distance between any two cities or locations available in The World Clock. Large-scale movements of the Earth's crust uplifted the mountain ranges that divided the ancient Tethys Ocean into several water basins, such as the Paratethys Ocean. com and vesselfinder. Let’s break down the formulas: Nautical Miles: A nautical mile is a unit of measurement used in navigation and represents approximately. You can use it free of charge! Everything is api-driven, if you like to integrate Searoutes into your own solution, please have a look into our api documentation or contact our sales manager. SeaRates. It includes conversions for speed and distance units. We have developed custom routing algorithms, and leverage. See also a map, estimated flight duration, carbon dioxide emissions and the time difference between Seattle and Seoul. Where do I get to when I dig a hole in SEA through the centre of the earth?Port to Port Sea Distance Calculator. Seattle-Tacoma International Airport [SEA] – Ultimate Terminal Guide. We have developed custom routing algorithms, and leverage. The maximum width of the sea is 355 km, and the sea’s deepest point is 3,040 m at the central Suakin Trough, with the sea’s estimated. For example, if there is a barrier in the way, you have to detour. There are many tour options that take travelers to Masada and the Dead Sea from Jerusalem. 75 km) north of the equator, so it is located in the northern hemisphere. DD), degrees and decimal minutes (DD:MM. SeaRates today. Contribute to eurostat/searoute development by creating an account on GitHub. • Unauthorized Access is strictly prohibited. Sinai on day 64-65 and he added 12 “arbitrary” filler days to delay the arrival from day 53 to day 65. 1. Cost Savings Along the NSR. Take the line 256 bus from Tel Aviv-Savidor Train Stations/Platforms A to Ha'Eucalyptus/HaYam Road 256. The breadth of the territorial sea,. Sao Tome and Principe. Yes, as long as you are using a hands-free telephone device and the voice-activated 511 function. Antipode: -47. Copyright © 2023 by SEA-DISTANCES. C. The Jason-3 satellite uses radio waves and other instruments to measure the height of the ocean's surface – also known as sea level.