If you work with maps, location data, or GPS coordinates, you probably know this situation: You have a latitude and longitude pair such as: 37.4219983, -122.084 And suddenly you need to answer five more questions: Where exactly is this? What address does it belong to? What's the elevation? What places are nearby? Is the coordinate itself even correct? Of course, all of these problems can be solved with APIs and a few lines of JavaScript. But sometimes you don't want to build anything. You just want to check the data. That's why I built CoordMap, a small collection of browser-based map utilities for working with coordinates and locations. The problem with debugging location data When developing location-based applications, I often find myself switching between several tools. One site for coordinates. Another for reverse geocoding. Another for elevation. Another map for visually checking whether a point is actually where I expect it to be. For example, imagine an API returns: { "latitude": 40.7484, "longitude": -73.9857 } Before using that result in an application, I may want to quickly inspect it on a map. Instead of creating a temporary map page or sending another API request, I can paste the coordinates into a coordinate finder and visually verify the location. This sounds trivial, but it becomes surprisingly useful when working with: delivery applications travel websites GPS tracking geocoding APIs weather applications hiking tools location-based search map interfaces Address → coordinates One of the most common tasks is geocoding. You start with something like: 1600 Amphitheatre Parkway, Mountain View and need something like: 37.xxxxxx, -122.xxxxxx In production applications, you would normally use a geocoding API. But during development, manually testing an address first is often useful. For example, if your API returns an unexpected location, checking the same address independently can help determine whether the problem is your application, your query formatting, or the underlying geocoder. Coordinates → address The opposite operation is equally useful. Suppose your browser gives you a position: navigator.geolocation.getCurrentPosition((position) => { console.log(position.coords.latitude); console.log(position.coords.longitude); }); Now you have two numbers. That's useful for a computer, but not particularly useful to a person. Reverse geocoding converts those coordinates into a human-readable place or address. During development, I often paste GPS coordinates directly into a map before integrating reverse geocoding into the application. It makes debugging much faster. Decimal coordinates vs DMS Coordinates also appear in different formats. Most web APIs use decimal degrees: 51.5074, -0.1278 But GPS devices, documents, and traditional maps may use degrees, minutes, and seconds: 51°30'26.6"N 0°07'40.1"W The conversion itself isn't difficult. For example: function decimalToDMS(decimal) { const degrees = Math.floor(Math.abs(decimal)); const minutesFloat = (Math.abs(decimal) - degrees) * 60; const minutes = Math.floor(minutesFloat); const seconds = (minutesFloat - minutes) * 60; return { degrees, minutes, seconds }; } But if I only need to convert one coordinate while debugging something, opening a converter is usually faster than writing or running code. Checking elevation Coordinates are two-dimensional, but many real-world applications need a third value: elevation. This becomes useful for things like: hiking applications cycling routes outdoor travel terrain visualization GPS photo metadata geographic analysis Elevation data should generally be treated as an estimate unless you're using survey-grade data, but it's still useful for quickly understanding a location. A point at 20 meters above sea level and a point at 2,000 meters can obviously behave very differently in an outdoor or weather-related application. Finding nearby places Another common location workflow starts with a coordinate and asks: What's around here? For an application, this usually means calling a places API. For debugging, however, it's useful to visually inspect nearby places first. Given: latitude = 48.8584 longitude = 2.2945 you may want to see nearby restaurants, hotels, landmarks, or other points of interest before deciding how your application should present the results. This is particularly helpful when testing location search radius logic. For example: const searchRadius = 1000; // meters A radius that works well in Manhattan may behave very differently in a rural area. Looking at the map helps make those differences obvious. A small tool I built for this I eventually put these workflows together into one site: https://www.coordmap.com/ The idea behind CoordMap is intentionally simple: Paste an address or coordinate, inspect it on a map, and continue exploring from there. It includes tools for working with latitude and longitude, checking your current location, exploring elevation, discovering nearby places, converting coordinate formats, measuring distance, browsing a world map, and working with other common geographic information. There's no need to create an account just to use the basic map tools. I mainly use it as a quick companion when developing or testing location-related features. Tools don't replace APIs A browser tool like this isn't intended to replace a proper geospatial stack. If you're processing thousands of coordinates, you should use an API or a geographic database. If you're calculating large datasets, use libraries such as Turf.js, PostGIS, or other GIS tools. And if location is a critical part of your application, you should understand the accuracy and limitations of your underlying data sources. But for questions like: "Where is this coordinate?" or: "Did my geocoder return the right place?" or: "What's near this point?" sometimes opening a map is simply the fastest solution. That's the problem I wanted CoordMap to solve. If you work with maps or location data, you can try it here: 👉 https://www.coordmap.com/ I'd also be interested to know which small geographic utilities you use most often while developing location-based applications.