Image Export Formats

[Midgardsormr]

Table of Contents

Introduction

Raster Formats

• Key Terms
• Bitmap
• GIF
• Jpeg
• PNG
• TIFF
• Targa
• OpenEXR
• Photoshop Document

Vector Formats

Introduction to Image Formats

There are several common image formats we use in creating maps. The purpose of this thread is to examine each of those formats, explain their strengths and weaknesses, and try to give some guidelines on when to use each one.

First, there are two broad groups of formats: raster vs vector. A raster image is simply a grid of colored pixels (dots on your screen). Most images you see on the web are raster images, described by their resolution of horizontal and vertical pixels. The term "bitmap" is sometimes used interchangeably with raster. Raster images are defined by their resolution ( 800 X 600, for instance, meaning 800 pixels wide by 600 pixels tall ), and their color depth, or bit-depth. The color depth refers to how many possible colors there are in the image. I'll not go into the technical details of color depth here, but if you want further reading, try this article: http://www.luminous-landscape.com/tu...it-depth.shtml

The other group of image formats are vector images. A vector graphic is described by mathematical formulae that the imaging software interprets and displays. Vector image formulas are continuous, so they are not limited by the resolution of the original picture. This means you can zoom in on a vector image and never see the ugly jaggies associated with increased magnification on a raster image. Unfortunately, web support for vector formats is limited, so although you can create images in a vector format, you will almost certainly have to export to a raster format if you want to share your work on the Internet. Many printshops can accept a variety of vector image formats, though, so if your target output is print, you can stay in vector from beginning to end if you so desire.