1. Procedural Output Steps
Note symbol design rules:
a. Determine purpose of map output and scale
b. Which theme layers and/or attribute codes (items)
c. Design map elements: symbols and colours
d. Design map layout
- Use of design variables following cartographic conventions
- Qualitative (nominal) versus quantitative (ordinal, interval) data
- Choice of boundary line or area fill for polygons
- Colour - avoid dark solids, be aware of screen to print differences - RGB versus CMYK
2. Design Layout
The following are key components of map design:
- Boxes: can be used to hold keys, sections or maps together
- Legend: defines whatever items are not self-explanatory
- Title: is required to define content
- Scale: required, usually as scale bar (RF can be problematic), divisons by round logical numbers
- North arrow: is often redundant if North is 'up' (but usually included)
- UTM or Latitude/longitude ticks
- Data source and map designer ( = metadata)
- Laser Printers (mostly monochrome) (letter -> tabloid)
- Ink jet Printers (letter -> rolls 36 or 54" wide)
Monochrome: cheaper, can be photocopied: is colour necessary and usable (cost)
Colour: is required for much output, due to complexity.
*In the 1980s pen plotters were the main output device for GIS: patterns were used for polygon fills, outlines for symbols;
From the 1990s, ink jet Printers are by far the most common, colour fills are easier, but solid colours can be too intense.
*Other changes have been increased resolution and quality of Printing media.
Sheets < 11 x 17": Ink jet or Laser Prinrers ($100+)
Roll > 11 x 17": Ink jet (36 or 54 " drum). (10,000+)
Measured in dots per inch (dpi). 300 dpi was a standard for most of the 90s; 600 and 1200 are now commonly available, and useful for photographic type output and sharper text.
Common graphic output formats
Postscript (PS) [Encapsulated Postscript (EPS)].
*Hewlett Packard Graphics Language (HPGL). Adobe Acrobat Portable Document Format (PDF)
Until the 1990s, output was a 'weak link' in the GIS process: many users transferred data to another program to Print maps. In the 1990s major vendors also introduced 'viewer' software for easier map production e.g. Arcview (ESRI), GeoMedia (Intergraph). Some still prefer export to a design package such as Adobe Illustrator (although not for industrial production).
Automated command scripts
In Arc/Info, maps were produced using AML = 'Arc Macro Language'
These allow the construction of a text file that contains a series of commands to be executed as one command.
Others such as ArcGIS use Visual Basic scripts
Menus can also be built for the customisation of the display interface
Things you should know after finishing this lecture:
- Why do large companies use scripts for map output
- What are the most common Printers used today for GIS output?
- What items do NO need to go in the legend
- Why is scale best given in a scale bar