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 20518 2009-03-05 23:39:46Z jimg $"
00033     };
00034 
00035 #include <cmath>
00036 
00037 #include <iostream>
00038 #include <sstream>
00039 
00040 //#define DODS_DEBUG
00041 
00042 #include "debug.h"
00043 #include "dods-datatypes.h"
00044 #include "GridGeoConstraint.h"
00045 #include "Float64.h"
00046 
00047 #include "Error.h"
00048 #include "InternalErr.h"
00049 #include "ce_functions.h"
00050 #include "util.h"
00051 
00052 using namespace std;
00053 
00054 namespace libdap {
00055 
00056 
00065 GridGeoConstraint::GridGeoConstraint(Grid *grid)
00066         : GeoConstraint(), d_grid(grid), d_latitude(0), d_longitude(0)
00067 {
00068     if (d_grid->get_array()->dimensions() < 2
00069         || d_grid->get_array()->dimensions() > 3)
00070         throw Error("The geogrid() function works only with Grids of two or three dimensions.");
00071 
00072     // Is this Grid a geo-referenced grid? Throw Error if not.
00073     if (!build_lat_lon_maps())
00074         throw Error(string("The grid '") + d_grid->name()
00075                     +
00076                     "' does not have identifiable latitude/longitude map vectors.");
00077 
00078     if (!lat_lon_dimensions_ok())
00079         throw Error("The geogrid() function will only work when the Grid's Longitude and Latitude\nmaps are the rightmost dimensions.");
00080 }
00081 
00097 bool GridGeoConstraint::build_lat_lon_maps()
00098 {
00099     Grid::Map_iter m = d_grid->map_begin();
00100     // Assume that a Grid is correct and thus has exactly as many maps at its
00101     // array part has dimensions. Thus don't bother to test the Grid's array
00102     // dimension iterator for '!= dim_end()'.
00103     Array::Dim_iter d = d_grid->get_array()->dim_begin();
00104     // The fields d_latitude and d_longitude are initialized to null
00105     while (m != d_grid->map_end() && (!d_latitude || !d_longitude)) {
00106         string units_value = (*m)->get_attr_table().get_attr("units");
00107         units_value = remove_quotes(units_value);
00108         string map_name = (*m)->name();
00109 
00110         // The 'units' attribute must match exactly; the name only needs to
00111         // match a prefix.
00112         if (!d_latitude
00113             && unit_or_name_match(get_coards_lat_units(), get_lat_names(),
00114                                   units_value, map_name)) {
00115 
00116             // Set both d_latitude (a pointer to the real map vector) and
00117             // d_lat, a vector of the values represented as doubles. It's easier
00118             // to work with d_lat, but it's d_latitude that needs to be set
00119             // when constraining the grid. Also, record the grid variable's
00120             // dimension iterator so that it's easier to set the Grid's Array
00121             // (which also has to be constrained).
00122             d_latitude = dynamic_cast < Array * >(*m);
00123             if (!d_latitude)
00124                 throw InternalErr(__FILE__, __LINE__, "Expected an array.");
00125             if (!d_latitude->read_p())
00126                 d_latitude->read();
00127 
00128             set_lat(extract_double_array(d_latitude));   // throws Error
00129             set_lat_length(d_latitude->length());
00130 
00131             set_lat_dim(d);
00132         }
00133 
00134         if (!d_longitude        // && !units_value.empty()
00135             && unit_or_name_match(get_coards_lon_units(), get_lon_names(),
00136                                   units_value, map_name)) {
00137 
00138             d_longitude = dynamic_cast < Array * >(*m);
00139             if (!d_longitude)
00140                 throw InternalErr(__FILE__, __LINE__, "Expected an array.");
00141             if (!d_longitude->read_p())
00142                 d_longitude->read();
00143 
00144             set_lon(extract_double_array(d_longitude));
00145             set_lon_length(d_longitude->length());
00146 
00147             set_lon_dim(d);
00148         }
00149 
00150         ++m;
00151         ++d;
00152     }
00153 
00154     return get_lat() && get_lon();
00155 }
00156 
00167 bool
00168 GridGeoConstraint::lat_lon_dimensions_ok()
00169 {
00170     // get the last two map iterators
00171     Grid::Map_riter rightmost = d_grid->map_rbegin();
00172     Grid::Map_riter next_rightmost = rightmost + 1;
00173 
00174     if (*rightmost == d_longitude && *next_rightmost == d_latitude)
00175         set_longitude_rightmost(true);
00176     else if (*rightmost == d_latitude && *next_rightmost == d_longitude)
00177         set_longitude_rightmost(false);
00178     else
00179         return false;
00180 
00181     return true;
00182 }
00183 
00205 void GridGeoConstraint::apply_constraint_to_data()
00206 {
00207     if (!get_bounding_box_set())
00208         throw
00209         InternalErr
00210         ("The Latitude and Longitude constraints must be set before calling apply_constraint_to_data().");
00211 
00212     Array::Dim_iter fd = d_latitude->dim_begin();
00213     if (get_latitude_sense() == inverted) {
00214         int tmp = get_latitude_index_top();
00215         set_latitude_index_top(get_latitude_index_bottom());
00216         set_latitude_index_bottom(tmp);
00217     }
00218 
00219     // It's esy to flip the Latitude values; if the bottom index value
00220     // is before/above the top index, return an error explaining that.
00221     if (get_latitude_index_top() > get_latitude_index_bottom())
00222         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.");
00223 
00224     // Constrain the lat vector and lat dim of the array
00225     d_latitude->add_constraint(fd, get_latitude_index_top(), 1,
00226                                get_latitude_index_bottom());
00227     d_grid->get_array()->add_constraint(get_lat_dim(),
00228                                         get_latitude_index_top(), 1,
00229                                         get_latitude_index_bottom());
00230 
00231     // Does the longitude constraint cross the edge of the longitude vector?
00232     // If so, reorder the grid's data (array), longitude map vector and the
00233     // local vector of longitude data used for computation.
00234     if (get_longitude_index_left() > get_longitude_index_right()) {
00235         reorder_longitude_map(get_longitude_index_left());
00236 
00237         // If the longitude constraint is 'split', join the two parts, reload
00238         // the data into the Grid's Array and make sure the Array is marked as
00239         // already read. This should be true for the whole Grid, but if some
00240         // future modification changes that, the array will be covered here.
00241         // Note that the following method only reads the data out and stores
00242         // it in this object after joining the two parts. The method
00243         // apply_constraint_to_data() transfers the data back from the this
00244         // objet to the DAP Grid variable.
00245         reorder_data_longitude_axis(*d_grid->get_array());
00246 
00247         // Now the data are all in local storage
00248 
00249         // alter the indices; the left index has now been moved to 0, and the right
00250         // index is now at lon_vector_length-left+right.
00251         set_longitude_index_right(get_lon_length() - get_longitude_index_left()
00252                                   + get_longitude_index_right());
00253         set_longitude_index_left(0);
00254     }
00255     // If the constraint used the -180/179 (neg_pos) notation, transform
00256     // the longitude map s it uses the -180/179 notation. Note that at this
00257     // point, d_longitude always uses the pos notation because of the earlier
00258     // conditional transformation.
00259 
00260     // Do this _before_ applying the constraint since set_array_using_double()
00261     // tests the array length using Vector::length() and that method returns
00262     // the length _as constrained_. We want to move all of the longitude
00263     // values from d_lon back into the map, not just the number that will be
00264     // sent (although an optimization might do this, it's hard to imagine
00265     // it would gain much).
00266     if (get_longitude_notation() == neg_pos) {
00267         transform_longitude_to_neg_pos_notation();
00268     }
00269     // Apply constraint; stride is always one and maps only have one dimension
00270     fd = d_longitude->dim_begin();
00271     d_longitude->add_constraint(fd, get_longitude_index_left(), 1,
00272                                 get_longitude_index_right());
00273 
00274     d_grid->get_array()->add_constraint(get_lon_dim(),
00275                                         get_longitude_index_left(),
00276                                         1, get_longitude_index_right());
00277 
00278     // Transfer values from the local lat vector to the Grid's
00279     set_array_using_double(d_latitude, get_lat() + get_latitude_index_top(),
00280                            get_latitude_index_bottom() - get_latitude_index_top() + 1);
00281 
00282     set_array_using_double(d_longitude, get_lon() + get_longitude_index_left(),
00283                            get_longitude_index_right() - get_longitude_index_left() + 1);
00284 
00285     // ... and then the Grid's array if it has been read.
00286     if (get_array_data()) {
00287 /* ***/
00288         int size = d_grid->get_array()->val2buf(get_array_data());
00289 
00290         if (size != get_array_data_size())
00291             throw
00292             InternalErr
00293             ("Expected data size not copied to the Grid's buffer.");
00294         d_grid->set_read_p(true);
00295     }
00296     else {
00297         d_grid->get_array()->read();
00298     }
00299 }
00300 
00301 } // namespace libdap

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