Large format maps are an indispensable tool in the GIS mapping industry. They offer comprehensive visual renditions of complex geographic areas. But to fully utilise these maps—namely, to organise and analyse the various locations and boundaries of Earth—they must be appropriately sized and fit to scale before being printed.

To resize and print oversized maps, careful scaling techniques must be undertaken. This will ensure that, once printed, the detail in the maps remains of optimal quality and is decipherable by users. In this article, we will uncover the process of scaling oversized maps for print jobs using such techniques. Whether you're a map designer, an architect, or a topographer, understanding the nuances of resizing large format maps is crucial for generating high-quality printouts that effectively communicate geographic information.

Large format maps are an essential part of many planning, logistics, ecological, and navigation practices. Large format maps help experts to:

• Plan buildings
• Manage city zones
• Chart geological features
• Track ecological trends
• Navigate buried utilities
• And much more

Large format maps are posted at construction sites and used for both wilderness and urban navigation. Experts also use them to study trends like disease outbreaks that occur over geographical areas. Large maps may display the features of a focused area closely or a large area in great detail.

Scaling is essential for large format maps because they are used for many precise projects. When an oversized map is not correctly scaled, the dimensions of the map will not be scientifically or logistically useful. There must be a consistent scale that translates exactly when the map is enlarged and is unwarped when the map is printed.

GIS maps come in many highly accurate file types. But printers have more narrow requirements. Therefore, you need to save your map in a file type that scales accurately. We suggest vector graphic file types like SVG, PNG, and PSG, which provide lossless scaling and printer-ready images.

Resolutions for map printing are measured in DPI or Dots Per Inch. We recommend 150 dpi to 300 dpi for most high-resolution maps.

The right size for your map printout depends on the project and where the map will be assembled. Determine the dimensions of the space where the map needs to be presented and how the map's original size ratio (ex: 1:3 vs 1:1 length/width) fits in that space.

Your map dimensions will be the length/width size ratio that fits within the presentation size. For example, if you need a map that is 200 cm long (wide) and has a length/width ratio of 2:1, your final dimensions will be 200 by 100 cm.

If your goal is to present a map large enough to provide detail over a large area, then sizing will ideally range between 'poster board' and 'mural' dimensions. This means your longest dimension is likely between 1.5 and 12 metres in length, depending on how you plan to display and use the map.

In your map editor or vector image editing program, locate the dimension scaling tool. Lock the two values together so that they scale with the same aspect ratio. Then adjust the larger number to your ideal map size.

There are two options for tiling that divides your map into separate paper-size-limited sections to be reassembled later: image editing and printer settings.

In image editing, use a grid to separate your map into sections. Then create separate sections with a small amount of overlap (cutting and reassembly margin for error) before printing each section separately.

In printer settings, your printer may have a tiling or "poster" mode that will automatically slice up your large format map into smaller printable sections. Give yourself a small margin (paper larger than the printed area) for each for cutting and reassembly.

Image interpolation can be used instead of vector scaling if your map's original format risks loss when scaled up. This is common using pixel/raster graphics. Interpolation "connects the dots" when an image is scaled, and pixels become further apart, creating shading instead of pixelation.

Vector graphics are ideal for image scaling because details are based on point-to-point angle and ratio rather than pixel coordinates. Scale a vector graphic up or down (or both), and the image will stay exactly the same.

If you prefer grid overlay mapping, then you can use the exact same aspect ratio increases to scale each grid individually.

Adobe Photoshop has a range of image editing tools that can help you precisely scale and resize maps while maintaining image quality and resolution.

GIS software like ArcGIS and QGIS provides advanced mapping capabilities, including scaling tools tailored for maps and spatial data.

AutoCAD is widely used in engineering and architecture. Its features accommodate high-detail projects, including large-scale maps with layered data. This software offers powerful scaling features for the accurate resizing of maps and technical drawings.

Adobe Illustrator is ideal for working with vector-based maps, enabling precise scaling without loss of quality. Vector editing is also ideal for adjusting your map key and notations so that your labels look right when scaled while maintaining accurate notation.

Specialised software designed for large format printing like ONYX or Caldera can offer scaling features, colour management, and more refined control over your printer settings for scaled and tiled map creation.

This is a physical tool that allows you to measure and scale maps accurately by maintaining the proportional relationship between distances.

Large format scanners can provide high-resolution digital copies for easy scaling and printing. This is clearly ideal when your original map is already printed and you need to scale, edit, or reprint.

When you're ready to print your large format map, using the right printer, settings, and format will determine the final quality of your map prints and how the pieces will be assembled based on paper size, margins, and overlap.

Large format printers are ideal for large format maps because the paper can cover a wider area per tile. Large format printers often use paper rolls so that you can accommodate your longest dimension and use map strips instead of letter-sized tiles. You can even choose more durable types of paper for a more durable final map.

Consider the level of ink detail needed. Adjust your printer settings to the colour balance and potential bleed during the printing process.

Before committing to a final print:

1. Run a few test prints.
2. Make sure your tiling settings are correct.
3. Ensure the ink and paper combination provides the right level of detail and that tiled map pieces fit together for final production.

GIS map printing is a demanding operation for any printer, even high-end large format printers designed for the purpose. To improve your GIS map printing results, reach out to HP for helpful guidance on GIS map printing solutions.

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• https://vincmazet.github.io/bip/interpolation/interpolation.html
• https://www.outlookmaps.com/map-sizes-dimensions
• https://www.assetally.com/articles/2018/8/31/pi8bwqagb91r3rzg7ueyoycr4zaktq
• https://freegeographytools.com/2007/printing-large-maps-on-a-small-printer
• https://support.esri.com/en-us/knowledge-base/how-to-print-a-large-map-as-panels-or-tiles-with-arcpre-000006355
• https://www.caliper.com/learning/articles/how-can-i-setup-my-map-to-print-at-large-scales/