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STUTTGART

TECHNIK

Background 

        STUTTGART UNIVERSITY OF APPLIED 

SCIENCES 

Vector formats are newly implemented into geographic mapping and becoming more 

and  more  popular.  They  are  actual  vectors  of  data  stored  in  mathematical  formats 

rather than bits of colored dots. This formatting falls into a lot of proprietary formats, 

formats  made  for  specific  programs.  CorelDraw  (CDR),  Hewlett Packard  Graphics 

Language  (HGL),  Windows  Metafiles  (EMF),  SVG  (Scalable  Vector  Graphic)  and 

WebCGM (Web Computer Graphics Metafile). 

2.3.1  Raster image formats 

A raster image file is generally defined to be a rectangular array of regularly sampled 

values,  known  as  pixels.  Each  pixel  (picture  element)  has  one  or  more  numbers 

associated with it, generally specifying a color which the pixel should be displayed in.   

The most common file format that used for mobile device is PNG (Portable Network 

Graphics).  PNG  is  a  bitmap  format  that  was  developed  by  the  World  Wide  Web 

Consortium  especially  for  the  web;  it  is  fully  streamable  with  a  progressive  display 

option.   

The PNG format has several advantages over other graphics  formats;  for example,  it 

is  license  free  and  supports  true  color  images,  including  a  full  transparency  (alpha) 

channel.  PNG  images  are  always  compressed  with  a  loss less  algorithm.  The 

algorithm  is  identical  to  the  algorithm  used  for  JAR  files,  so  the  mobile 

implementation can save space by using the same algorithm for both purposes. 

2.3.2    Vector image formats 

Vector  image  files  record  images  descriptively,  in  terms  of  geometric  shapes.  These 

shapes are converted to bitmaps for display on the monitor. Vector images are easier 

to  modify,  because  the  components  can  be  moved,  resized,  rotated,  or  deleted 

independently. The W3C has produced an XML based format called Scalable Vector 

Graphics (SVG). SVG has been widely used in GIS Internet mapping purpose, and it 

is more optimal compared to other vector image formats.   

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