You can georeference a scanned map online using browser-based tools that let you align the image to real-world coordinates. We built this capability directly into Gratic because cartographers often need to update older maps or trace features from historical surveys. Our goal was to avoid a broken workflow. Instead of using one tool to warp an image and another to draw, Gratic lets you do both in the same browser tab, so you can start drawing immediately.
Managing the distortion in old scanned maps
Beyond simply aligning points, the main challenge is managing the distortions inherent in old paper maps and integrating the result into a modern vector workflow. A scanned map is not a perfect representation of the ground. The original paper may have stretched or shrunk unevenly. The survey itself might have contained errors, or it may have been drawn using a projection that is difficult to reconcile with modern satellite data. The scanner can also introduce its own lens distortion.
Many tools treat georeferencing as a separate, preliminary step. An excellent open-source tool like Map Warper, for instance, focuses entirely on rectification. You upload an image, match control points to a basemap, and it generates a rectified image file, like a GeoTIFF. This is useful if your goal is to create a warped image for use in various desktop GIS programs. But for a cartographer making a new map, that file is just another intermediate asset to manage. You still have to import it into your primary drawing software.
We wanted to solve the cartographer's problem, not just the image-warping problem. The ultimate goal is a new, clean vector map. The scanned image is a source, a guide, a reference layer—but it is temporary. The workflow should reflect that.
Forcing a mapper to jump between different applications for rectification and drawing adds friction and complexity. It breaks the creative flow. That’s why we decided the georeferencing function had to live inside the editor itself, as a fundamental part of the map creation process.
Treating the georeferenced image as a live tracing layer
An editor should treat a georeferenced image not as a final product, but as a live tracing layer that is part of the project file. This is a different approach from standalone rectification tools like Map Warper. Such tools are excellent for their specific purpose: you upload an image, match control points, and download a rectified image file like a GeoTIFF. This is ideal for one-off tasks or when you need a georeferenced image for use in various desktop GIS programs.
The limitation for a cartographer is that this rectified file is an intermediate step. It must then be imported into a separate drawing program. We built Gratic to avoid this broken workflow. Once you align your scanned map in Gratic, it becomes an interactive part of your workspace, not just a static background image. You can adjust its transparency to see the vector lines you are drawing, or toggle it off to check your work against the fresh contour and road data Gratic pulls in from our servers.
The purpose of georeferencing in Gratic is to enable drawing. You align your scan, and then you immediately pick up a pen tool and start tracing a path or building using standard orienteering symbol sets. The workflow is uninterrupted. Because the alignment is non-destructive, you can go back and adjust the control points if you notice a misalignment as you draw, without starting over. The georeferenced layer and your new vector layers are linked within the same project—just as a cartographer thinks of their map.
From alignment to a finished vector map
After the map is aligned, the real cartography begins: tracing features, applying standard symbols, and building a new, clean vector map from your source material. The alignment itself is just the setup. The main event is drawing. In Gratic, once your scanned map is in place, you are in a complete cartographic environment. You can immediately begin using the pen tools, which are designed to feel right for a mapper, to draw trails, fences, and water features directly over the scan.
Because Gratic is built for terrain and orienteering maps, it can also pull in other relevant data for your chosen area. You can overlay automatically generated contours from our elevation data or import vector data for roads and streams from national mapping services. This allows you to cross-reference your scanned map with modern data, helping you decide which features to keep, which to discard, and which to correct. You are not just blindly tracing an old document; you are creating a new, more accurate map by synthesizing multiple sources.
All of this work—the georeferencing, the tracing, the symbolization, the layering of external data—is saved as a single project file. When you are finished, you are not left with a warped raster image. You have a crisp vector map. And because we know that professional workflows often involve multiple tools, the files you create in Gratic are designed to open directly in OCAD. The entire process, from uploading a dusty scanned map to exporting a clean OCAD file, happens in a single browser tab, with nothing to install.
Frequently Asked Questions
Can I use any scanned map in Gratic?
Yes, as long as it is a standard image file. The key is having visible points on your scan—like road intersections or distinct buildings—that you can match to real-world locations. Gratic helps you find these locations by letting you pull in vector data from national mapping services directly into the editor, providing a reliable reference for placing your control points.
Does the georeferenced map file work with OCAD?
The georeferencing information itself is part of the Gratic project. The goal is to create a new map, not just warp an old image. When you are done drawing, you export the new vector map you have created. That file, with all your new objects and standard symbols, is what opens in OCAD for final touches or printing.
Do I need to install any software for this?
No. The entire process happens in your browser. You upload your scan, georeference it, draw your new map over it, and export the final file without ever leaving the browser tab. There is nothing to install and nothing to license.