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1 gross 4106 \chapter{Data Sources}\label{Chp:ref:data sources}
2    
3 caltinay 4145 At the source of every inversion is data in the form of gravity anomaly or
4     magnetic flux density values for at least a part of the region of interest.
5     These usually come from surveys and are preprocessed to correct for various
6     factors and distortions.
7     This chapter provides an overview of the classes related to data input for
8     inversions.
9    
10 gross 4106 \section{General Interface}
11 caltinay 4145 The inversion module comes with a number of classes that can read gridded
12     (raster) data on a 2-dimensional plane from file or provide artificial values
13     for testing purposes. These classes all derive from the abstract
14     \class{DataSource} class and override methods that return information about
15     the data and the values themselves.
16     The \class{DomainBuilder} class is responsible for creating an \escript domain
17     with a suitable grid spacing and spatial extents that include all data sources
18     attached to it (see Figure~\ref{fig:domainBuilder}).
19     %
20     \begin{figure}[ht]
21     \centering\includegraphics{domainbuilder}
22     \caption{\class{DataSource} instances are added to a \class{DomainBuilder}
23     which creates a suitable domain and \Data objects for the inversion}
24     \label{fig:domainBuilder}
25     \end{figure}
26     %
27     Notice that in the figure there are cells in the region of interest that are
28     not covered by any data source instance.
29     Ideally, all data sources used for an inversion have the same spatial resolution
30     and are spatially adjacent so that all cells have a value but this is not a
31     requirement.
32 gross 4106
33 caltinay 4145
34 gross 4131 \section{Domain Builder}\label{Chp:ref:domain builder}
35 caltinay 4145 Every inversion requires one \class{DomainBuilder} instance which has the
36     following methods:
37 gross 4106
38 caltinay 4145 \begin{classdesc}{DomainBuilder}{\optional{dim=3}}
39     Constructor for the domain builder. \member{dim} sets the dimensionality of the
40     target domain and must be 2 or 3. By default a 3-dimensional domain is created.
41     \end{classdesc}
42 gross 4106
43 caltinay 4145 \begin{methoddesc}[DomainBuilder]{addSource}{source}
44     Adds survey data \member{source} (a \class{DataSource} object) to the domain
45     builder. The dimensionality of the data must be less than or equal to the
46     domain dimensionality.
47     \end{methoddesc}
48    
49     \begin{methoddesc}[DomainBuilder]{getDomain}{}
50     returns the \escript domain of the inversion, see~\cite{ESCRIPT}.
51     \end{methoddesc}
52    
53     \section{ER Mapper Raster Data}
54    
55 gross 4106 \section{NetCDF Data}
56 caltinay 4145 An example script how to create a data input file for both gravity and magnetic data using the NetCDF file format~\cite{netcdf}
57     is available in the script \examplefile{create_ncinput.py}. To plot an input file using matplotlib~\cite{matplotlib}
58 gross 4119 is avilable in the script \examplefile{show_ncinput.py}.
59 gross 4106
60     \section{Synthetic Data}
61 caltinay 4145

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