Creating a terrain map in a browser requires a true cartography editor that works with live data, not just an image generator. I built Gratic as a vector editor for this purpose. It pulls in elevation and vector data automatically, giving you live contours and standard symbols to draw with. Everything happens in your browser, and the result is a file that opens directly in OCAD for your existing workflow.
The difference between a map generator and a map editor
A map generator produces a static output like an image or 3D model, while a map editor gives you tools to draw and modify vector data. Many browser tools are generators. They take real-world elevation data and create a visual representation, which can be useful. For example, 3D Map Generator is excellent for creating a striking 3D view of a trail, and its companion Free Heightmap Generator can give you a high-resolution heightmap image to use as a base layer. These are powerful for visualization, but they are not cartography tools. Their output is the final product.
Once a generator creates its image or model, you cannot easily change a single contour line or move one building. The entire map is a single, flat object. If you need to correct the course of a stream or reclassify a path, you would have to go back to the start and regenerate the entire map with different settings, if the tool even allows it. This is a fundamental limitation for anyone doing serious cartography. A map is rarely perfect on the first try; it requires refinement based on field checking and local knowledge.
This is why I built Gratic as a vector editor. Instead of a single image, a map in Gratic is a collection of individual objects. Every contour, path, fence, and building is a separate piece of data you can select, modify, or delete. If a fence needs its ticks corrected, you change the symbol for that object.
If a trail is drawn incorrectly, you move its vertices. This is how cartography software has always worked, and I saw no reason to abandon that principle just because the editor runs in a browser. The goal isn't just to see the terrain, but to draw an accurate representation of it.
Getting real-world data into a browser-based editor
We built Gratic to import elevation and vector data automatically when you select an area on the map. My goal was to remove the tedious step of hunting for data files before you can even start drawing. The workflow is direct: you open a tab, find the location you want to map, and drag a rectangle over it. Gratic then fetches the necessary data for that specific area. You don't need to know what a DEM file is or where to download one.
Behind the scenes, two things happen. First, the editor pulls elevation data from our own tiled data sets to generate the contour lines. Second, it imports vector data—like roads, streams, and buildings—from national mapping services. This gives you an immediate, symbolized base map to work from, not just a blank canvas or a background image to trace. The contours are live vector lines, and the roads are paths you can edit, not just pixels in an image. It’s a real map from the first second.
This integrated approach differs from many other workflows. Some tools require you to find and upload your own data files. Others, like cotamap.com, are very effective at processing specific data sources like LiDAR to generate a base map, which you then take to the field. Gratic integrates the data acquisition and editing into one continuous process. We are also transparent about our sources. On our site, we publish a complete list of the national mapping services we import from, including their license terms, so you know exactly what you are working with.
Drawing a real terrain map
Drawing a terrain map involves tracing features, applying standard symbols, and adjusting objects until the map is clear and accurate. A piece of software must be built for this specific task. It needs to provide the right tools, not just a generic set of drawing functions. When I started building Gratic, I focused on the specific needs of orienteering and terrain cartography. This meant implementing standard ISOM symbol sets and creating pens that behave the way a mapper expects them to.
For instance, when you draw a line, you are not just setting its color and width. You are choosing a symbol, like a small earth bank or a stone wall, and the editor handles the correct dashes, ticks, and spacing for you. This is crucial for efficiency and for creating a map that other people in the sport can read. The process is one of constant refinement. You might draw a path based on aerial imagery, then adjust it after walking the ground yourself. In Gratic, you just click and drag the line's points to match reality.
Ultimately, a map made in a browser has to be useful outside the browser. The final step for most mappers is layout and printing, which is often handled by specialized desktop software. That is why we made sure that files from Gratic open cleanly in OCAD. The work you do in the browser is not trapped there. You are creating a standard map file that fits into a professional production workflow. The browser becomes a powerful, installation-free tool for the most time-consuming part of the job: drawing the ground itself.
Frequently asked questions
Q: Do I need to install anything? A: No. Gratic is a map editor that runs entirely in your browser tab. There is nothing to install or license. You sign in with an email, we send you a code, and you can start drawing immediately.
Q: Can I use my existing OCAD files? A: Gratic is designed to fit into a professional workflow. Our files are built to open directly in OCAD, ensuring compatibility with the tools you already use for final layout and printing.
Q: Where does the map data come from? A: We pull data from two main sources. We hold our own tiled elevation data for contours, and for vector features like roads and rivers, we import directly from national mapping services. We publish a full, transparent list of these providers and their license terms.
Q: Is this for real maps or fantasy maps? A: Gratic is a vector cartography editor for real-world orienteering and terrain maps. While some browser tools are built for fictional worlds, our focus is on providing accurate data and professional symbols for mapping actual ground.