GIS Maps for Offset Printing
This section describes how to create maps from GIS for use in offset-printed publications.
Going from GIS to offset printing is not for the faint of heart! If you do want to place your GIS-based map into a document that will be offset printed, here are some basic guidelines:
- Offset printing is used for large quantity and or high quality prints/publications/reports (over 500-1000 copies).
- Offset printers use CMYK color where as most GIS packages export using RGB colors (more on this below).
- When doing an offset print of your map, confer with your designer and/or printer early and often!
- It is a good idea to do a press check at the printer for critical pieces, before the full printing begins.
- In the past publications were done in two colors to save money, but today the cost difference between 2 color and 4 color may not be as significant as the time and effort in preparing GIS data for job (showing many features with just two colors takes much more effort than using many colors).
In evaluating your choices, one of the key factors is that computers display colors in Red/Green/Blue (RGB) mode, while printers use devices that create documents in Cyan/Magenta/Yellow/Black (CMYK) mode. Understanding this difference is critical to ensuring your offset printed map matches your expectations. LEARN MORE about color modes...
Approach 1: Simple Export, Uncertain Results
The easiest approach is to export a graphic image of your map, from your GIS software, and then to place that image in your document publishing software. But:
- Exporting a high resolution image from a GIS software package may provide you with adequate resolution (sharpness) but the actual colors that are printed are highly unpredictable.
- Most GIS software allows for a 600dpi EPS or TIF file to be exported. This image should be brought into a image editing software and converted to a CMYK image prior to conducting test prints.
- You should definitely test your print by sending it to a pre-press production service where a color-approved print can be created. This print will generally show how the map will appear when printed, and may cost $80-120. If the image is generally acceptable, great - otherwise, you'll need to move to Approach 2:
Approach 2: Export Directly to Illustration Software
This approach uses GIS software to export a final map in a file that can preserve the "layers" of data and text when used in illustration software such as Adobe Illustrator or Freehand. However, the following guidelines should be considered:
- In your (ESRI) GIS, follow these practices:
- Export from the DataFrame not the PageLayout
- Do not use transparency (this will rasterize layers)
- Export vector files separately (points, polygons and lines)
- Export raster files and edit with your image software -- don't forget to convert them to CMYK -- then place the image in your illustration file. Some rescaling may need to take place.
- It is good practice to export more area than you think you'll need --also good to take notes on projection and scale used.
Approach 3: Using Intermediate Software for Export
- Avenza's MapPublisher software can be very useful for managing the export process from GIS to Illustrator or Freehand software. It is fairly expensive (over $500), but if you frequently export maps for offset, it can be well worth the cost, because it:
- Allows attribute data to be associated with features;
- Keeps georeferencing information with data - important if data will be added to future maps;
- Very useful if geometry is for a specific area; and
- Available for both Mac and PC platforms (Illustrator or Freehand).
- However - this software will take some time to fully understand - it is quite complex. Training is available, but generally costs $700/day or more.
- Shaded relief layers can be exported
at 150dpi (dots per inch), even if your printer says they shouldn’t be (only in this
case, ignore the printer's advice) – otherwise those map images can become very large with no
gain in production value.
Return to Advanced GIS Techniques <<<