Master

'

s Thesis 2006 

FACHHOCHSCHULE

HOCHSCHULE F

U

R

LI Hui 

STUTTGART

TECHNIK

Background 

        STUTTGART UNIVERSITY OF APPLIED 

SCIENCES 

Following  the  same  principle,  a  valid  request  should  include  all  the  mandatory 

parameters. In the URL above, 

http://www.gis news.de/wms/getmapcap.php?

 gives 

the  server  name  and  the  path  of  the  file  resource  on  the  server. 

VERSION=1.1.1

indicates 

the 

server 

supports 

OGC 

WMS 

version 

1.1.1 

and 

REQUEST=GetCapabilities

tells 

the 

request 

name. 

BBOX=189775.33,4816305.37,761662.27,5472414.18

  and 

SRS

2

=EPSG

3

:  26715

define  the  bounding  box  which  indicates  the  specific  required  region  in  the  given 

coordinates  system. 

HEIGHT=800

  and 

WIDTH=600

  defines  the  size  of  the 

image. 

FORMAT=image/svg+xml

  defines  the  output  format  of  the  image  in  this 

case  it  is  SVG  format. 

LAYERS=

airports,ctybdpy2,AUSSTATE1

defines  the 

layers  which  requested  by  the  user.  The  result  of  the  GetMap  request  is  a  vector  or 

raster image map to be displayed in the browser. All the parameters should be picked 

up from the GetCapabilities XML Document. 

The  GetFeatureInfo  request  is  an  option.  It  has  not  been  involved  in  the 

implementation of this thesis, so it will not be discussed here. 

2.3  Graphic data formats 

As  discussed  above,  the  output  image  format  is  a  very  important  parameter  of  the 

GetMap  request.  At  the  moment  there  are  more  than  44  different  graphic  format 

names,  but  there  actually  are  only  two  basic  methods  for  a  computer  to  render,  or 

store and display an image: raster image format and vector image format.   

Raster  image  formats  (RIFs)  should  be  the  most familiar  to  Internet  users.  A  Raster 

format  breaks  the  image  into  a  series  of  colored  dots  called  pixels.  The  number  of 

ones and zeros (bits) used to create each pixel denotes the depth of color you can put 

into  your  images.  There  are  various  raster  image  formats  available  such  as  Tagged 

Image  File  Format  (TIFF),  Graphics  Interchange  Format  (GIF),  Joint  Photographic 

Expert Group (JPEG) and Standard Windows Bitmap (BMP).   

2

  Spatial Reference System 

3

  European Petroleum Survey Group (http://www.epsg.org) 

11