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    1 #!F-adobe-helvetica-medium-r-normal--18*
    2 #!N 
    3 #!CSlateBlue #!N  #!Rqimd Importing Data #!N #!EC #!N #!N Importing data 
    4 into Data Explorer is the first step in creating a visualization 
    5 of that data. Data Explorer supports the importation of a number 
    6 of data formats: General Array Importer, Data Explorer native, CDF, netCDF, 
    7 and HDF (see  #!Limd,dxall618 h Importing Data: File Formats  #!EL  in IBM Visualization Data Explorer User's Guide). 
    8 The General Array Importer is discussed here not only because it 
    9 can import a variety of data types but because its supporting 
   10 interface makes it useful to the broadest range of users. This 
   11 interface consists of the Data Prompter, for describing the data to 
   12 be imported, and the Data Browser, for viewing the data. #!N 
   13 #!N This chapter deals with the importation of data in the 
   14 following sections: #!N #!I0 #!N  #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N o 
   15  #!Lgai,dxall110 h General Array Importer  #!EL  #!N #!I30 #!N o  #!Lgaiexs,dxall114 h Importing Data: Header File Examples  #!EL  #!N #!I30 #!N o  #!Lsydfgi,dxall139 h Header File Syntax: Keyword Statements  #!EL  
   16 #!N #!I30 #!N o  #!Lprompt,dxall157 h Data Prompter  #!EL  #!N #!I30 #!N o  #!Lbrowse,dxall169 h Data Prompter Browser  #!EL  #!N 
   17 #!I0 #!N #!EF #!N #!CIndianRed #!N #!N #!N  #!F-adobe-times-bold-r-normal--18*   An Important 
   18 Note on Fields #!N #!N Importing data into Data Explorer requires 
   19 some knowledge of the Data Explorer data model and at least 
   20 a working knowledge of a  #!F-adobe-times-medium-i-normal--18*   field #!EF . #!N #!N 
   21  #!F-adobe-times-medium-i-normal--18*   Fields #!EF are the fundamental objects in the Data Explorer 
   22 data model. A field represents a mapping from some  #!F-adobe-times-medium-i-normal--18*   domain 
   23 #!EF to some  #!F-adobe-times-medium-i-normal--18*   data space #!EF . The domain of 
   24 the mapping is specified by a set of  #!F-adobe-times-medium-i-normal--18*   positions #!EF 
   25 and (generally) a set of  #!F-adobe-times-medium-i-normal--18*   connections #!EF that allow interpolation 
   26 of data values for points between positions. Positions represent what can 
   27 be thought of as (and often really are) locations in space; 
   28 the data are the values associated with the space of the 
   29 positions. The mapping at all points in a domain (not just 
   30 those specified by the given positions) is represented implicitly by specifying 
   31 that the data are dependent on (located at) the sample points 
   32 or on the connections between points. #!N #!N This simple abstraction 
   33 is sufficient for representing a wide range of information. For example, 
   34 you can describe 3-dimensional volumetric data whose domain is the region 
   35 specified by positions and whose data space is the set of 
   36 values associated with those positions. The domain of a 2-dimensional image 
   37 on a monitor screen is a set of pixel locations, and 
   38 the data space consists of the pixel color. For 2-dimensional surfaces 
   39 imbedded in 3-dimensional space (e.g., traditional graphical models) the domain may 
   40 be a set of positions on the surface, and the data 
   41 space a set of data values on that surface. #!N #!N 
   42 In Data Explorer the positions and data are said to be 
   43  #!F-adobe-times-medium-i-normal--18*   components #!EF of a field, and every field must contain 
   44 at least a "positions" component and a "data" component. Fields may 
   45 also contain other components (e.g., "connections"). Thus a Data Explorer field 
   46 consists of data and the additional components needed to describe that 
   47 data so that Data Explorer can process it. #!N #!N  #!F-adobe-times-bold-r-normal--18*   
   48 (cont.) #!EF #!N #!N #!EC #!CIndianRed #!N #!N #!N  #!F-adobe-times-bold-r-normal--18*   An 
   49 Important Note on Fields (cont.) #!N #!N Components are represented as 
   50 arrays of numbers with some auxiliary information specifying  #!F-adobe-times-medium-i-normal--18*   attributes #!EF 
   51 (e.g., type of data dependency). The syntax of defining fields in 
   52 the General Array format is described in  #!Lsydfgi,dxall139 h Header File Syntax: Keyword Statements  #!EL  . The various 
   53 components are described in IBM Visualization Data Explorer User's Guide. #!N 
   54 #!N #!EC #!N #!N #!N  #!F-adobe-times-medium-i-normal--18*   Next Topic #!EF #!N #!N 
   55  #!Lgai,dxall110 h General Array Importer  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N