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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