Class Raster

Inheritance Relationships

Derived Type

Class Documentation

class Raster

Interface to an Elevation Reader based on a rectangular grid of pixels (i.e.

posts).

Subclassed by navtk::geospatial::GdalRaster

Public Functions

virtual ~Raster() = default
virtual int get_width() const = 0

Returns the total number of pixels in each line.

Returns

The number of pixels in the line.

virtual int get_height() const = 0

Returns the total number of lines in the dataset object (i.e.

in the file).

Returns

The number of lines.

virtual std::pair<double, double> wgs84_to_pixel(double latitude, double longitude) const = 0

Transform the coordinates from wgs84 (lat/lon) to pixel offset.

The pixel offset is the decimal distance from the top left of the tile, must be converted to an int to get a specific pixel index.

Parameters

  • latitude – latitude in degrees

  • longitude – longitude in degrees

Returns

The converted coordinates as a pixel offset from the top left of the tile.

virtual double read_pixel(size_t idx_x, size_t idx_y) = 0

Returns a single double representing the elevation at the given pixel index.

Parameters

  • idx_x – index of pixel in the line, value should be between 0 and get_width().

  • idx_y – index of line to read, value should be between 0 and get_height().

Returns

The elevation at the pixel index, or no_data_value if the requested index is unavailable in the dataset or is out of bounds.

virtual std::string get_name() const = 0

Return a human-readable name for this object.

Returns

The file name.

virtual bool is_valid_data(double data) const = 0

Compare the given elevation to the raster’s no data value.

Parameters

data – The elevation to evaluate.

Returns

true if the elevation is valid and false if not.

virtual void unload() = 0

Remove data from memory, if cached.

Public Members

double no_data_value

Datasets define a value which they use to denote invalid or missing data inside of a tile.

If any elevation matches this value then it is invalid.

std::unique_ptr<GDALDataset, detail::DatasetDelete> dataset

A unique pointer to a GDALDataset object with a custom deleter.