GeoConstraint Class Reference

#include <GeoConstraint.h>

Inheritance diagram for GeoConstraint:

Inheritance graph
[legend]
Collaboration diagram for GeoConstraint:

Collaboration graph
[legend]
List of all members.

Public Types

 inverted
enum  LatitudeSense { unknown_sense, normal, inverted }
 neg_pos
 normal
enum  Notation { unknown_notation, pos, neg_pos }
 pos
 unknown_notation
 unknown_sense

Public Member Functions

virtual void apply_constraint_to_data ()=0
 Once the bounding box is set use this method to apply the constraint.
void set_bounding_box (double left, double top, double right, double bottom)
virtual ~GeoConstraint ()
Constructors
 GeoConstraint (const string &ds_name)
 Initialize GeoConstraint with a Grid.

Protected Member Functions

virtual bool build_lat_lon_maps ()=0
virtual LatitudeSense categorize_latitude () const
Notation categorize_notation (double left, double right) const
void find_latitude_indeces (double top, double bottom, LatitudeSense sense, int &latitude_index_top, int &latitude_index_bottom) const
void find_longitude_indeces (double left, double right, int &longitude_index_left, int &longitude_index_right) const
virtual bool is_bounding_box_valid (double left, double top, double right, double bottom) const
virtual bool lat_lon_dimensions_ok ()=0
virtual void reorder_data_longitude_axis (Array &a)
virtual void reorder_longitude_map (int longitude_index_left)
void transform_constraint_to_pos_notation (double &left, double &right) const
virtual void transform_longitude_to_neg_pos_notation ()
virtual void transform_longitude_to_pos_notation ()

Friends

class GridGeoConstraintTest

Detailed Description

Encapsulate the logic needed to handle geographical constraints when they are applied to DAP Grid (and some Array) variables.

This class will apply a longitude/latitude bounding box to a Grid that is a 'geo-referenced' Grid. That is, it follows the COARDS/CF conventions. This may be relaxed...

If the longitude range of the constraint crosses the boundary of the data array so that the constraint creates two separate rectangles, this class will arrange to return the result as a single Grid. It will do this by rearranging the data before control is passed onto the constraint evaluator and serialization logic. Here's a diagram of how it works:

Suppose a constraint for the longitude BB starts at the left edge of L and goes to the right edge of R:

       0.0       180.0       360.0 (longitude, in degrees)
        +----------------------+
        |xxxxxyyyyyyyyyyyyzzzzz|
        -----+            +-----
        |    |            |    |
        | R  |            | L  |
        |    |            |    |
        -----+            +-----
        |                      |
        +----------------------+
    

For example, suppose the client provides a bounding box that starts at 200 degrees and ends at 80. This class will first copy the Left part to new storage and then copy the right part, thus 'stitching together' the two halves of the constraint. The result looks like:

     80.0  360.0/0.0  180.0  ~200.0 (longitude, in degrees)
        +----------------------+
        |zzzzzxxxxxxyyyyyyyyyyy|
        -----++-----           |
        |    ||    |           |
        | L  || R  |           |
        |    ||    |           |
        -----++-----           |
        |                      |
        +----------------------+
    

The changes are made in the Grid variable itself, so once this is done the Grid should not be re-read by the CE or serialization code.

Author:
James Gallagher

Definition at line 100 of file GeoConstraint.h.


Member Enumeration Documentation

enum GeoConstraint::LatitudeSense

Most of the time, latitude starts at the top of an array with positive values and ends up at the bottom with negative ones. But sometimes... the world is upside down.

Enumerator:
unknown_sense 
normal 
inverted 

Definition at line 115 of file GeoConstraint.h.

enum GeoConstraint::Notation

The longitude extents of the constraint bounding box can be expressed two ways: using a 0/359 notation and using a -180/179 notation. I call the 0/359 notation 'pos' and the -180/179 notation 'neg_pos'.

Enumerator:
unknown_notation 
pos 
neg_pos 

Definition at line 106 of file GeoConstraint.h.


Constructor & Destructor Documentation

GeoConstraint::GeoConstraint ( const string &  ds_name  ) 

Parameters:
grid Set the GeoConstraint to use this Grid variable. It is the caller's responsibility to ensure that the value grid is a valid Grid variable.
ds_name The name of the dataset. Passed to BaseType::read().
dds Use this DDS to get global attributes.

Definition at line 521 of file GeoConstraint.cc.

virtual GeoConstraint::~GeoConstraint (  )  [inline, virtual]

Definition at line 214 of file GeoConstraint.h.


Member Function Documentation

virtual void GeoConstraint::apply_constraint_to_data (  )  [pure virtual]

Implemented in ArrayGeoConstraint, and GridGeoConstraint.

virtual bool GeoConstraint::build_lat_lon_maps (  )  [protected, pure virtual]

A protected method that searches for latitude and longitude map vectors and sets six key internal fields. This method returns false if either map cannot be found.

The d_lon, d_lon_length and d_lon_dim (and matching lat) fields must be set by this method.

Returns:
True if the maps are found, otherwise False

GeoConstraint::LatitudeSense GeoConstraint::categorize_latitude (  )  const [protected, virtual]

Take a look at the latitude vector values and record whether the world is normal or upside down.

Returns:
normal or inverted.

Definition at line 332 of file GeoConstraint.cc.

References inverted, and normal.

Referenced by set_bounding_box().

GeoConstraint::Notation GeoConstraint::categorize_notation ( double  left,
double  right 
) const [protected]

A private method that determines if the longitude part of the bounding box uses 0/359 or -180/179 notation. This class only supports latitude constriants which use 90/-90 notation, so there's no need to figure out what sort of notation they use.

Note:
This function assumes that if one of the two values is negative, then the notation is or the -180/179 form, otherwise not. If the user asks for 30 degrees to 50 degress (or 50 to 30, for that matter), there's no real way to tell which notation they are using.
Parameters:
left The left side of the bounding box, in degrees
right The right side of the boubding box
Returns:
The notation (pos or neg_pos)

Definition at line 128 of file GeoConstraint.cc.

References neg_pos, and pos.

Referenced by set_bounding_box().

void GeoConstraint::find_latitude_indeces ( double  top,
double  bottom,
LatitudeSense  sense,
int &  latitude_index_top,
int &  latitude_index_bottom 
) const [protected]

Scan from the top to the bottom, and the bottom to the top, looking for the top and bottom bounding box edges, respectively.

Parameters:
top The top edge of the bounding box
bottom The bottom edge
latitude_index_top Value-result parameter that holds the index in the grid's latitude map of the top bounding box edge. Uses a closed interval for the test.
latitude_index_bottom Value-result parameter for the bottom edge index.

Definition at line 289 of file GeoConstraint.cc.

References normal.

Referenced by set_bounding_box().

void GeoConstraint::find_longitude_indeces ( double  left,
double  right,
int &  longitude_index_left,
int &  longitude_index_right 
) const [protected]

Scan from the left to the right, and the right to the left, looking for the left and right bounding box edges, respectively.

Parameters:
left The left edge of the bounding box
right The right edge
d_longitude_index_left Value-result parameter that holds the index in the grid's longitude map of the left bounding box edge. Uses a closed interval for the test.
d_longitude_index_right Value-result parameter for the right edge index.

Definition at line 201 of file GeoConstraint.cc.

References DBG2.

Referenced by set_bounding_box().

char* GeoConstraint::get_array_data (  )  const [inline]

Definition at line 229 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

int GeoConstraint::get_array_data_size (  )  const [inline]

Definition at line 233 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

bool GeoConstraint::get_bounding_box_set (  )  const [inline]

Definition at line 324 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

set<string> GeoConstraint::get_coards_lat_units (  )  const [inline]

Definition at line 354 of file GeoConstraint.h.

set<string> GeoConstraint::get_coards_lon_units (  )  const [inline]

Definition at line 358 of file GeoConstraint.h.

string GeoConstraint::get_dataset (  )  const [inline]

Definition at line 223 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), ArrayGeoConstraint::apply_constraint_to_data(), and reorder_data_longitude_axis().

double* GeoConstraint::get_lat (  )  const [inline]

Definition at line 238 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data().

Array::Dim_iter GeoConstraint::get_lat_dim (  )  const [inline]

Definition at line 276 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

int GeoConstraint::get_lat_length (  )  const [inline]

Definition at line 255 of file GeoConstraint.h.

set<string> GeoConstraint::get_lat_names (  )  const [inline]

Definition at line 363 of file GeoConstraint.h.

int GeoConstraint::get_latitude_index_bottom (  )  const [inline]

Definition at line 294 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

int GeoConstraint::get_latitude_index_top (  )  const [inline]

Definition at line 290 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

LatitudeSense GeoConstraint::get_latitude_sense (  )  const [inline]

Definition at line 341 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

double* GeoConstraint::get_lon (  )  const [inline]

Definition at line 242 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data().

Array::Dim_iter GeoConstraint::get_lon_dim (  )  const [inline]

Definition at line 272 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

int GeoConstraint::get_lon_length (  )  const [inline]

Definition at line 259 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), ArrayGeoConstraint::apply_constraint_to_data(), and reorder_data_longitude_axis().

set<string> GeoConstraint::get_lon_names (  )  const [inline]

Definition at line 367 of file GeoConstraint.h.

int GeoConstraint::get_longitude_index_left (  )  const [inline]

Definition at line 307 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), ArrayGeoConstraint::apply_constraint_to_data(), and reorder_data_longitude_axis().

int GeoConstraint::get_longitude_index_right (  )  const [inline]

Definition at line 311 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), ArrayGeoConstraint::apply_constraint_to_data(), and reorder_data_longitude_axis().

Notation GeoConstraint::get_longitude_notation (  )  const [inline]

Definition at line 337 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data().

bool GeoConstraint::get_longitude_rightmost (  )  const [inline]

Definition at line 328 of file GeoConstraint.h.

Referenced by reorder_data_longitude_axis().

bool GeoConstraint::is_bounding_box_valid ( double  left,
double  top,
double  right,
double  bottom 
) const [protected, virtual]

Definition at line 169 of file GeoConstraint.cc.

References normal.

Referenced by set_bounding_box().

virtual bool GeoConstraint::lat_lon_dimensions_ok (  )  [protected, pure virtual]

Are the latitude and longitude dimensions ordered so that this class can properly constrain the data? This method throws Error if lat and lon are not to two 'fastest-varying' (or 'rightmost) dimensions. It sets the internal property longitude_rightmost if that's true.

Note:
Called by the constructor once build_lat_lon_maps() has returned.
Returns:
True if the lat/lon maps are the two rightmost maps, false otherwise

void GeoConstraint::reorder_data_longitude_axis ( Array a  )  [protected, virtual]

Reorder the data values relative to the longitude axis so that the reordered longitude map (see GeoConstraint::reorder_longitude_map()) and the data values match.

Note:
This method should set the d_array_data and d_array_data_size fields. If those are set, apply_constraint_to_data() will use those values.

First set all the other constraints, including the latitude and then make this call. Other constraints, besides latitude, will be simple range constraints. Latitude might require that values be inverted, but that can be done _after_ the longitude reordering takes place. The latitude constraint can be imposed by inverting the top and bottom indices if the sense of the grid is inverted, before data are read in this method. Then apply the longitude constraint, then invert the result of the merge, if needed.

Todo:
Fix this code so that it works with latitude as the rightmost map

Definition at line 417 of file GeoConstraint.cc.

References Array::add_constraint(), Vector::buf2val(), DBG, DBG2, get_dataset(), get_lon_length(), get_longitude_index_left(), get_longitude_index_right(), get_longitude_rightmost(), Array::print_val(), BaseType::read(), Vector::set_read_p(), Vector::var(), and BaseType::width().

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

Here is the call graph for this function:

void GeoConstraint::reorder_longitude_map ( int  longitude_index_left  )  [protected, virtual]

Reorder the elements in the longitude map so that the longitude constraint no longer crosses the edge of the map's storage. The d_lon field is modified.

Note:
The d_lon vector always has double values regardless of the type of d_longitude.
Parameters:
d_longitude_index_left The left edge of the bounding box.

Definition at line 377 of file GeoConstraint.cc.

Referenced by GridGeoConstraint::apply_constraint_to_data().

void GeoConstraint::set_bounding_box ( double  left,
double  top,
double  right,
double  bottom 
)

Set the bounding box for this constraint. After calling this method the object has values for the indexes for the latitude and longitude extent as well as the sense of the latitude (south pole at the top or bottom of the Array or Grid). These are used by the apply_constraint_to_data() method to actually constrain the data.

Parameters:
left The left side of the bounding box.
right The right side
top The top
bottom The bottom

Definition at line 560 of file GeoConstraint.cc.

References categorize_latitude(), categorize_notation(), DBG, double_to_string(), find_latitude_indeces(), find_longitude_indeces(), is_bounding_box_valid(), neg_pos, transform_constraint_to_pos_notation(), and transform_longitude_to_pos_notation().

Referenced by libdap::function_geoarray(), and libdap::function_geogrid().

Here is the call graph for this function:

void GeoConstraint::set_lat ( double *  lat  )  [inline]

Definition at line 246 of file GeoConstraint.h.

void GeoConstraint::set_lat_dim ( Array::Dim_iter  lat  )  [inline]

Definition at line 284 of file GeoConstraint.h.

void GeoConstraint::set_lat_length ( int  len  )  [inline]

Definition at line 263 of file GeoConstraint.h.

void GeoConstraint::set_latitude_index_bottom ( int  bottom  )  [inline]

Definition at line 302 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

void GeoConstraint::set_latitude_index_top ( int  top  )  [inline]

Definition at line 298 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

void GeoConstraint::set_latitude_sense ( LatitudeSense  l  )  [inline]

Definition at line 349 of file GeoConstraint.h.

void GeoConstraint::set_lon ( double *  lon  )  [inline]

Definition at line 250 of file GeoConstraint.h.

void GeoConstraint::set_lon_dim ( Array::Dim_iter  lon  )  [inline]

Definition at line 280 of file GeoConstraint.h.

void GeoConstraint::set_lon_length ( int  len  )  [inline]

Definition at line 267 of file GeoConstraint.h.

void GeoConstraint::set_longitude_index_left ( int  left  )  [inline]

Definition at line 315 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

void GeoConstraint::set_longitude_index_right ( int  right  )  [inline]

Definition at line 319 of file GeoConstraint.h.

Referenced by GridGeoConstraint::apply_constraint_to_data(), and ArrayGeoConstraint::apply_constraint_to_data().

void GeoConstraint::set_longitude_notation ( Notation  n  )  [inline]

Definition at line 345 of file GeoConstraint.h.

void GeoConstraint::set_longitude_rightmost ( bool  state  )  [inline]

Definition at line 332 of file GeoConstraint.h.

void GeoConstraint::transform_constraint_to_pos_notation ( double &  left,
double &  right 
) const [protected]

Definition at line 139 of file GeoConstraint.cc.

Referenced by set_bounding_box().

void GeoConstraint::transform_longitude_to_neg_pos_notation (  )  [protected, virtual]

Given that the Grid has a longitude map that uses the 'pos' notation, transform it to the 'neg_pos' notation. This method modifies the d_longitude Array.

Definition at line 163 of file GeoConstraint.cc.

Referenced by GridGeoConstraint::apply_constraint_to_data().

void GeoConstraint::transform_longitude_to_pos_notation (  )  [protected, virtual]

Given that the Grid has a longitude map that uses the 'neg_pos' notation, transform it to the 'pos' notation. This method modifies the d_longitude Array.

Definition at line 151 of file GeoConstraint.cc.

Referenced by set_bounding_box().


Friends And Related Function Documentation

friend class GridGeoConstraintTest [friend]

Reimplemented in GridGeoConstraint.

Definition at line 206 of file GeoConstraint.h.


The documentation for this class was generated from the following files:
Generated on Wed Jun 27 12:57:54 2007 for libdap++ by  doxygen 1.4.7