GridGeoConstraint.cc

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00001 
00002 // -*- mode: c++; c-basic-offset:4 -*-
00003 
00004 // This file is part of libdap, A C++ implementation of the OPeNDAP Data
00005 // Access Protocol.
00006 
00007 // Copyright (c) 2002,2003 OPeNDAP, Inc.
00008 // Author: James Gallagher <jgallagher@opendap.org>
00009 //
00010 // This library is free software; you can redistribute it and/or
00011 // modify it under the terms of the GNU Lesser General Public
00012 // License as published by the Free Software Foundation; either
00013 // version 2.1 of the License, or (at your option) any later version.
00014 //
00015 // This library is distributed in the hope that it will be useful,
00016 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00017 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018 // Lesser General Public License for more details.
00019 //
00020 // You should have received a copy of the GNU Lesser General Public
00021 // License along with this library; if not, write to the Free Software
00022 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00023 //
00024 // You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
00025 
00026 // The Grid Selection Expression Clause class.
00027 
00028 
00029 #include "config.h"
00030 
00031 static char id[] not_used =
00032     { "$Id: GridGeoConstraint.cc 16966 2007-08-20 21:54:12Z jimg $"
00033     };
00034 
00035 #include <math.h>
00036 #include <string.h>
00037 
00038 #include <iostream>
00039 #include <sstream>
00040 
00041 //#define DODS_DEBUG
00042 
00043 #include "debug.h"
00044 #include "dods-datatypes.h"
00045 #include "GridGeoConstraint.h"
00046 #include "Float64.h"
00047 
00048 #include "Error.h"
00049 #include "InternalErr.h"
00050 #include "ce_functions.h"
00051 
00052 using namespace std;
00053 using namespace libdap;
00054 
00055 
00062 GridGeoConstraint::GridGeoConstraint(Grid *grid, const string &ds_name)
00063         : GeoConstraint(ds_name), d_grid(grid), d_latitude(0), d_longitude(0)
00064 {
00065     if (d_grid->get_array()->dimensions() < 2
00066         || d_grid->get_array()->dimensions() > 3)
00067         throw Error("The geogrid() function works only with Grids of two or three dimensions.");
00068 
00069     // Is this Grid a geo-referenced grid? Throw Error if not.
00070     if (!build_lat_lon_maps())
00071         throw Error(string("The grid '") + d_grid->name()
00072                     +
00073                     "' does not have identifiable latitude/longitude map vectors.");
00074 
00075     if (!lat_lon_dimensions_ok())
00076         throw Error("The geogrid() function will only work when the Grid's Longitude and Latitude\nmaps are the rightmost dimensions.");
00077 }
00078 
00094 bool GridGeoConstraint::build_lat_lon_maps()
00095 {
00096     Grid::Map_iter m = d_grid->map_begin();
00097     // Assume that a Grid is correct and thus has exactly as many maps at its
00098     // array part has dimensions. Thus don't bother to test the Grid's array
00099     // dimension iterator for '!= dim_end()'.
00100     Array::Dim_iter d = d_grid->get_array()->dim_begin();
00101     // The fields d_latitude and d_longitude are initialized to null
00102     while (m != d_grid->map_end() && (!d_latitude || !d_longitude)) {
00103         string units_value = (*m)->get_attr_table().get_attr("units");
00104         remove_quotes(units_value);
00105         string map_name = (*m)->name();
00106 
00107         // The 'units' attribute must match exactly; the name only needs to
00108         // match a prefix.
00109         if (!d_latitude
00110             && unit_or_name_match(get_coards_lat_units(), get_lat_names(),
00111                                   units_value, map_name)) {
00112 
00113             // Set both d_latitude (a pointer to the real map vector) and
00114             // d_lat, a vector of the values represented as doubles. It's easier
00115             // to work with d_lat, but it's d_latitude that needs to be set
00116             // when constraining the grid. Also, record the grid variable's
00117             // dimension iterator so that it's easier to set the Grid's Array
00118             // (which also has to be constrained).
00119             d_latitude = dynamic_cast < Array * >(*m);
00120             if (!d_latitude->read_p())
00121                 d_latitude->read(get_dataset());
00122 
00123             set_lat(extract_double_array(d_latitude));   // throws Error
00124             set_lat_length(d_latitude->length());
00125 
00126             set_lat_dim(d);
00127         }
00128 
00129         if (!d_longitude        // && !units_value.empty()
00130             && unit_or_name_match(get_coards_lon_units(), get_lon_names(),
00131                                   units_value, map_name)) {
00132 
00133             d_longitude = dynamic_cast < Array * >(*m);
00134             if (!d_longitude->read_p())
00135                 d_longitude->read(get_dataset());
00136 
00137             set_lon(extract_double_array(d_longitude));
00138             set_lon_length(d_longitude->length());
00139 
00140             set_lon_dim(d);
00141         }
00142 
00143         ++m;
00144         ++d;
00145     }
00146 
00147     return get_lat() && get_lon();
00148 }
00149 
00160 bool
00161 GridGeoConstraint::lat_lon_dimensions_ok()
00162 {
00163     // get the last two map iterators
00164     Grid::Map_riter rightmost = d_grid->map_rbegin();
00165     Grid::Map_riter next_rightmost = rightmost + 1;
00166 
00167     if (*rightmost == d_longitude && *next_rightmost == d_latitude)
00168         set_longitude_rightmost(true);
00169     else if (*rightmost == d_latitude && *next_rightmost == d_longitude)
00170         set_longitude_rightmost(false);
00171     else
00172         return false;
00173 
00174     return true;
00175 }
00176 
00198 void GridGeoConstraint::apply_constraint_to_data()
00199 {
00200     if (!get_bounding_box_set())
00201         throw
00202         InternalErr
00203         ("The Latitude and Longitude constraints must be set before calling apply_constraint_to_data().");
00204 
00205     Array::Dim_iter fd = d_latitude->dim_begin();
00206     if (get_latitude_sense() == inverted) {
00207         int tmp = get_latitude_index_top();
00208         set_latitude_index_top(get_latitude_index_bottom());
00209         set_latitude_index_bottom(tmp);
00210     }
00211 
00212     // It's esy to flip the Latitude values; if the bottom index value
00213     // is before/above the top index, return an error explaining that.
00214     if (get_latitude_index_top() > get_latitude_index_bottom())
00215         throw Error("The upper and lower latitude indices appear to be reversed. Please provide the latitude bounding box numbers giving the northern-most latitude first.");
00216 
00217     // Constrain the lat vector and lat dim of the array
00218     d_latitude->add_constraint(fd, get_latitude_index_top(), 1,
00219                                get_latitude_index_bottom());
00220     d_grid->get_array()->add_constraint(get_lat_dim(),
00221                                         get_latitude_index_top(), 1,
00222                                         get_latitude_index_bottom());
00223 
00224     // Does the longitude constraint cross the edge of the longitude vector?
00225     // If so, reorder the grid's data (array), longitude map vector and the
00226     // local vector of longitude data used for computation.
00227     if (get_longitude_index_left() > get_longitude_index_right()) {
00228         reorder_longitude_map(get_longitude_index_left());
00229 
00230         // If the longitude constraint is 'split', join the two parts, reload
00231         // the data into the Grid's Array and make sure the Array is marked as
00232         // already read. This should be true for the whole Grid, but if some
00233         // future modification changes that, the array will be covered here.
00234         // Note that the following method only reads the data out and stores
00235         // it in this object after joining the two parts. The method
00236         // apply_constraint_to_data() transfers the data back from the this
00237         // objet to the DAP Grid variable.
00238         reorder_data_longitude_axis(*d_grid->get_array());
00239 
00240         // Now the data are all in local storage
00241 
00242         // alter the indices; the left index has now been moved to 0, and the right
00243         // index is now at lon_vector_length-left+right.
00244         set_longitude_index_right(get_lon_length() - get_longitude_index_left()
00245                                   + get_longitude_index_right());
00246         set_longitude_index_left(0);
00247     }
00248     // If the constraint used the -180/179 (neg_pos) notation, transform
00249     // the longitude map s it uses the -180/179 notation. Note that at this
00250     // point, d_longitude always uses the pos notation because of the earlier
00251     // conditional transforamtion.
00252 
00253     // Do this _before_ applying the constraint since set_array_using_double()
00254     // tests the array length using Vector::length() and that method returns
00255     // the length _as constrained_. We want to move all of the longitude
00256     // values from d_lon back into the map, not just the number that will be
00257     // sent (although an optimization might do this, it's hard to imagine
00258     // it would gain much).
00259     if (get_longitude_notation() == neg_pos) {
00260         transform_longitude_to_neg_pos_notation();
00261     }
00262     // Apply constraint; stride is always one and maps only have one dimension
00263     fd = d_longitude->dim_begin();
00264     d_longitude->add_constraint(fd, get_longitude_index_left(), 1,
00265                                 get_longitude_index_right());
00266 
00267     d_grid->get_array()->add_constraint(get_lon_dim(),
00268                                         get_longitude_index_left(),
00269                                         1, get_longitude_index_right());
00270 
00271     // Transfer values from the local lat vector to the Grid's
00272     set_array_using_double(d_latitude, get_lat() + get_latitude_index_top(),
00273                            get_latitude_index_bottom() - get_latitude_index_top() + 1);
00274 
00275     set_array_using_double(d_longitude, get_lon() + get_longitude_index_left(),
00276                            get_longitude_index_right() - get_longitude_index_left() + 1);
00277 
00278     // ... and then the Grid's array if it has been read.
00279     if (get_array_data()) {
00280         int size = d_grid->get_array()->val2buf(get_array_data());
00281         if (size != get_array_data_size())
00282             throw
00283             InternalErr
00284             ("Expected data size not copied to the Grid's buffer.");
00285         d_grid->set_read_p(true);
00286     }
00287     else {
00288         d_grid->get_array()->read(get_dataset());
00289     }
00290 }

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