Changeset 5976
 Timestamp:
 Nov 19, 2008, 3:21:51 PM (15 years ago)
 Location:
 anuga_core
 Files:

 2 edited
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anuga_core/documentation/user_manual/anuga_user_manual.tex
r5956 r5976 1100 1100 indices refer to edges in the order they appear: Edge 0 connects vertex 0 and vertex 1, edge 1 connects vertex 1 and 2; and so forth. 1101 1101 (Here, the values associated with each boundary tag are oneelement lists, but they can have as many indices as there are edges) 1102 If polygons intersect, or edges coincide the resolution may be undefined in some regions.1102 If polygons intersect, or edges coincide (or are even very close) the resolution may be undefined in some regions. 1103 1103 Use the underlying mesh interface for such cases. See Section 1104 1104 \ref{sec:mesh interface}. … … 1906 1906 1907 1907 1908 \begin{methoddesc}{get\_vertex _coordinates}{absolute=False}1909 1908 \begin{methoddesc}{get\_vertex\_coordinates}{absolute=False} 1909 \label{pg:get vertex coordinates} 1910 1910 Return vertex coordinates for all triangles. 1911 1911 … … 1914 1914 M the number of triangles in the mesh. 1915 1915 1916 Boolean keyword argument absolute determines whether coordinates 1917 are to be made absolute by taking georeference into account 1918 Default is False as many parts of ANUGA expects relative coordinates. 1919 \end{methoddesc} 1920 1921 1922 \begin{methoddesc}{get\_centroid\_coordinates}{absolute=False} 1923 1924 Return centroid coordinates for all triangles. 1925 1926 Return all centroid coordinates for all triangles as a M x 2 array 1927 1916 1928 Boolean keyword argument absolute determines whether coordinates 1917 1929 are to be made absolute by taking georeference into account … … 2027 2039 \item \code{location} determines which part of the triangles to assign 2028 2040 to. Options are 'vertices' (default), 'edges', 'unique vertices', and 'centroids'. 2041 If 'vertices' are use, edge and centroid values are automatically computed as the appropriate averages. This option ensures continuity of the surface. 2042 If, on the other hand, 'centroids' is used vertex and edge values will be set to the same value effectively creating a piecewise constant surface with possible discontinuities at the edges. 2029 2043 \end{itemize} 2030 2044 … … 2551 2565 model will evolve through several steps internally 2552 2566 as the method forces the water speed to be calculated 2553 on successive new cells). The user 2567 on successive new cells). 2568 2569 The code specified by the user in the block following the evolve statement is only executed once every \code{yieldstep} even though 2570 ANUGA typically will take many more internal steps behind the scenes. 2571 2572 The user 2554 2573 specifies the total time period over which the evolution is to take 2555 2574 place, by specifying values (in seconds) for either \code{duration} … … 2617 2636 Module: \module{abstract\_2d\_finite\_volumes.domain} 2618 2637 2619 Allow access to individual quantities and their methods 2620 2638 This function returns a Quantity object Q. 2639 Access to it's values should be done through Q.get\__values documented on Page \pageref{pg:get values}. 2640 2621 2641 \end{funcdesc} 2622 2642 … … 2674 2694 2675 2695 \begin{funcdesc}{get\_values}{location='vertices', indices = None} 2696 \label{pg:get values} 2676 2697 Module: \module{abstract\_2d\_finite\_volumes.quantity} 2677 2698 2678 Extract values for quantity as an array 2679 2699 Extract values for quantity as a Numeric array. 2700 2701 {\small \begin{verbatim} 2702 Inputs: 2703 interpolation_points: List of x, y coordinates where value is 2704 sought (using interpolation). If points 2705 are given, values of location and indices 2706 are ignored. Assume either absolute UTM 2707 coordinates or geospatial data object. 2708 2709 location: Where values are to be stored. 2710 Permissible options are: vertices, edges, centroids 2711 and unique vertices. Default is 'vertices' 2712 2713 2714 The returned values will have the leading dimension equal to length of the indices list or 2715 N (all values) if indices is None. 2716 2717 In case of location == 'centroids' the dimension of returned 2718 values will be a list or a Numerical array of length N, N being 2719 the number of elements. 2720 2721 In case of location == 'vertices' or 'edges' the dimension of 2722 returned values will be of dimension Nx3 2723 2724 In case of location == 'unique vertices' the average value at 2725 each vertex will be returned and the dimension of returned values 2726 will be a 1d array of length "number of vertices" 2727 2728 Indices is the set of element ids that the operation applies to. 2729 2730 The values will be stored in elements following their 2731 internal ordering. 2732 2680 2733 \end{funcdesc} 2681 2734 … … 3030 3083 Chapter \ref{ch:getstarted}: 3031 3084 3085 %FIXME (Ole): Should put in example with nonzero xllcorner, yllcorner 3032 3086 \verbatiminput{examples/bedslopeexcerpt.cdl} 3033 3087 … … 3079 3133 3080 3134 A mesh file can also contain a georeference, which describes an 3081 offset to be applied to $x$ and $y$ values egto the vertices.3135 offset to be applied to $x$ and $y$ values  e.g.\ to the vertices. 3082 3136 3083 3137 … … 3091 3145 %\begin{verbatim} 3092 3146 3093 first line: 3147 first line: \code{[column names]}\\ 3094 3148 other lines: \code{[x value], [y value], [attributes]}\\ 3095 3149 … … 3566 3620 \chapter{Basic \anuga Assumptions} 3567 3621 3568 3622 \section{Time} 3569 3623 Physical model time cannot be earlier than 1 Jan 1970 00:00:00. 3570 3624 If one wished to recreate scenarios prior to that date it must be done 3571 3625 using some relative time (e.g. 0). 3572 3626 3573 3574 All spatial data relates to the WGS84 datum (or GDA94) and has been 3575 projected into UTM with false easting of 500000 and false northing of 3576 1000000 on the southern hemisphere (0 on the northern). 3577 3578 It is assumed that all computations take place within one UTM zone and 3579 all locations must consequently be specified in Cartesian coordinates 3627 The ANUGA domain has an attribute \code{starttime} which is used in cases where the simulation should be started later than the beginning of some input data such as those obtained from boundaries or forcing functions (hydrographs, file\_boundary etc) 3628 3629 The \code{file\_boundary} may adjust domain.startime in case the input data does not itself start until a later time. 3630 3631 3632 \section{Spatial data} 3633 3634 \subsection{Projection} 3635 All spatial data relates to the WGS84 datum (or GDA94) and assumes a projection into UTM with false easting of 500000 and false northing of 3636 1000000 on the southern hemisphere (0 on the northern hemisphere). 3637 All locations must consequently be specified in Cartesian coordinates 3580 3638 (eastings, northings) or (x,y) where the unit is metres. 3581 3582 DEMs, meshes and boundary conditions can have different origins within 3583 one UTM zone. However, the computation will use that of the mesh for 3584 numerical stability. 3585 3639 Alternative projections can be assumed, but ANUGA does have the concept of a UTM zone 3640 that must be the same for all coordinates in the model. 3641 3642 \subsection{Internal coordinates} 3643 It is important to realise that ANUGA for numerical precision uses coordinates that are relative 3644 to the lower left node of the rectangle containing the mesh ($x_$min, $y_$min). 3645 This origin is referred to internally as xllcorner, yllcorner following the ESRI ascii grid notation. 3646 The sww file format also includes xllcorner, yllcorner and any coordinate in the file should be adjusted 3647 by adding this origin. See Section \ref{sec:sww format}. 3648 3649 Throughout the ANUGA interface functions have optional boolean arguments \code{absolute} which control 3650 whether spatial data received is using the internal representation (absolute=False) or the 3651 user coordinate set (absolute=True). See e.g. \code{get\_vertex\_coordinates} on \pageref{pg:get vertex coordinates}. 3652 3653 DEMs, meshes and boundary conditions can have different origins. However, the internal representation in ANUGA 3654 will use the origin of the mesh. 3655 3656 \subsection{Polygons} 3586 3657 When generating a mesh it is assumed that polygons do not cross. 3587 3658 Having polygons tht cross can cause the mesh generation to fail or bad 
anuga_core/source/anuga/abstract_2d_finite_volumes/quantity.py
r5897 r5976 1084 1084 """get values for quantity 1085 1085 1086 return X, Compatible list, Numeric array (see below)1086 Extract values for quantity as a Numeric array. 1087 1087 1088 1088 Inputs: … … 1098 1098 1099 1099 1100 The returned values wi th be a list the length of indices1101 (N if indices = None).1100 The returned values will have the leading dimension equal to length of the indices list or 1101 N (all values) if indices is None. 1102 1102 1103 1103 In case of location == 'centroids' the dimension of returned
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