Unigine::Dataset Class

The Dataset class is used for processing raster and vector data with binding to geo-coordinates. The class uses GDAL API to retrieve data from files.

The class allows for loading such rare raster formats as .dem, .tiff (with information on binding to geo-coordinates), .ecw and vector formats .osm, .shp.

For raster data, geo-coordinates can be obtained per-pixel in the (latitude, longitude) format. Pixel values can be of different formats (R8, R16, R32F for single-channel data; RGB8, RGB16, RGB32F, RGBA8, RGBA16, RGBA32F for multi-channel data).

The following example shows how raster data can be accessed by using methods of the Dataset class:

// AppWorldLogic.cpp

#include <UnigineDataset.h>
#include <UnigineLog.h>
#include <UnigineEngine.h>
#include <UnigineImage.h>
#include <UnigineInterface.h>

int AppWorldLogic::init() {
	
	// create a new dataset
	DatasetPtr dataset = Dataset::create();
	// load raster data
	dataset->load("unigine_project/maps/geo.tif");
	// desclare images into which raster data obtained from the loaded dataset will be saved
	Vector<ImagePtr> raster_data;
	// print data on each raster band of the dataset
	for (int i = 0; i < dataset->getRasterCount(); i++) {
		Log::message("Band:  %d\n", i);
		Log::message("Type:  %s\n", dataset->getRasterTypeName(i));
		Log::message("Color: %s\n", dataset->getRasterColorName(i));

		ImagePtr image = Image::create();
		// create an image of the size and format of the current raster band
		image->create2D(dataset->getRasterSizeX(), dataset->getRasterSizeY(), Image::FORMAT_R8);
		// read the region of the current raster band into the created image
		if (dataset->getRasterImage(i, image) == 0) {			
			Log::error("Can't import raster band, layer: %d\n", i);
			continue;
		}
		// add the obtained raster data to the array
		raster_data.append(image);
	}

	for (int y = 0; y < dataset->getRasterSizeY(); y += dataset->getRasterSizeY() - 1) {
		for (int x = 0; x < dataset->getRasterSizeX(); x += dataset->getRasterSizeX() - 1) {
			double latitude = dataset->getLatitude(x, y);
			double longitude = dataset->getLongitude(x, y);
			Log::message("%4dx%-4d: %f / %f\n", x, y, latitude, longitude);
		}
	}
	
	return 1;
}

For vector data, the number of primitives, their points and properties can be obtained. You can also triangulate a primitive and save it to a dynamic mesh (see the samples_2/geodetics/dataset_00 sample).

Vector Dataset

// AppWorldLogic.cpp

#include <UnigineDataset.h>
#include <UnigineLog.h>
#include <UnigineEngine.h>
#include <UnigineInterface.h>

using namespace Unigine; 

int AppWorldLogic::init() {
	// create a new dataset
	DatasetPtr dataset = Dataset::create();
	// load vector data
	dataset->load("unigine_project/maps/antarctica.shp");
	// print information on the dataset layers
	for (int i = 0; i < dataset->getVectorCount(); i++) {
		Log::message("Layer:  %d\n", i);
		Log::message("Name:   %s\n", dataset->getVectorName(i));
		Log::message("Fields: %d\n", dataset->getVectorFieldCount(i));
		Log::message("Features:\n");
		// print field definitions and its assotiated values for each feature of the dataset layer
		// starting from the first feature
		dataset->vectorFeatureReadReset(i);
		// obtain the current feature
		while (dataset->vectorFeatureReadNext(i)) {
			// for each field definition of the current feature
			for (int j = 0; j < dataset->getVectorFieldCount(i); j++) {
				// get the name
				const char *field_name = dataset->getVectorFieldName(i, j);
				// get the assotiated value
				Variable field_value = dataset->getVectorFieldValue(i, j);
				// print the obtained values
				Log::message("\t%s: %s\n", field_name, field_value.getTypeInfo().get());
			}
		}
	}
	
	return 1;
}

Dataset Class

Members

static DatasetPtr create()

const char * getCreationData()

Return value

const char * getCreationOption()

Return value

const char * getDescription()

Return value

void getGeodeticPosition(int x, int y, double & latitude, double & longitude)

Arguments

• int x - X coordinate of the pixel.
• int y - Y coordinate of the pixel.
• double & latitude - North-south position in degrees.
• double & longitude - East-west position in degrees.

double getLatitude(int x, int y)

Arguments

• int x - X coordinate of the pixel.
• int y - Y coordinate of the pixel.

Return value

double getLongitude(int x, int y)

Arguments

• int x - X coordinate of the pixel.
• int y - Y coordinate of the pixel.

Return value

double getOriginX()

Return value

double getOriginY()

Return value

const char * getProjection()

Return value

const char * getRasterColorName(int num)

Arguments

• int num - Raster band number.

Return value

int getRasterCount()

Return value

int getRasterImage(int num, const Ptr<Image> & image, int offset_x = 0, int offset_y = 0)

Arguments

• int num - Raster band number.
• const Ptr<Image> & image - Image into which the raster band should be read.
• int offset_x - Pixel offset to the top left corner of the region of the band to be written. To start from the left, 0 should be specified.
• int offset_y - Line offset to the top left corner of the region of the band to be written. To start from the top, 0 should be specified.

Return value

int getRasterImageAllBands(const Ptr<Image> & image, int offset_x = 0, int offset_y = 0)

Arguments

• const Ptr<Image> & image - Image into which the raster bands should be read.
• int offset_x - Pixel offset to the top left corner of the region of the band to be accessed. To start from the left, 0 should be specified.
• int offset_y - Line offset to the top left corner of the region of the band to be accessed. To start from the top, 0 should be specified.

Return value

double getRasterMaximumValue(int num)

Arguments

• int num - Raster band number.

Return value

double getRasterMinimumValue(int num)

Arguments

• int num - Raster band number.

Return value

double getRasterNoDataValue(int num)

Arguments

• int num - Raster band number.

Return value

double getRasterOffset(int num)

Arguments

• int num - Raster band number.

Return value

int getRasterPosition(double latitude, double longitude, int & x, int & y)

Arguments

• double latitude - North-south position in degrees.
• double longitude - East-west position in degrees.
• int & x - X coordinate of the pixel.
• int & y - Y coordinate of the pixel.

Return value

int getRasterPosition(double latitude, double longitude, float & x, float & y)

Arguments

• double latitude - North-south position in degrees.
• double longitude - East-west position in degrees.
• float & x - X coordinate of the pixel.
• float & y - Y coordinate of the pixel.

Return value

void getRasterPositions(double * latitudes, double * longitude, int size, float * ret_x, float * ret_y, bool * ret_pixels)

Arguments

• double * latitudes - Array of north-south positions in degrees.
• double * longitude - Array of east-west positions in degrees.
• int size - Size of array of geodetic positions.
• float * ret_x - Array of X coordinates of pixels.
• float * ret_y - Array of Y coordinates of pixels.
• bool * ret_pixels - Array of values indicating if the transformed pixels are in the raster band: 1 if the pixel is in the raster band (x in range [0;raster_size_x]; y in range [0;raster_size_y]); otherwise, 0.

void getRasterPositions(double * latitudes, double * longitude, int size, int * ret_x, int * ret_y, bool * ret_pixels)

Arguments

• double * latitudes - Array of north-south positions in degrees.
• double * longitude - Array of east-west positions in degrees.
• int size - Size of array of geodetic positions.
• int * ret_x - Array of X coordinates of pixels.
• int * ret_y - Array of Y coordinates of pixels.
• bool * ret_pixels - Array of values indicating if the transformed pixels are in the raster band: 1 if the pixel is in the raster band (x in range [0;raster_size_x]; y in range [0;raster_size_y]); otherwise, 0.

double getRasterScale(int num)

Arguments

• int num - Raster band number.

Return value

int getRasterSizeX()

Return value

int getRasterSizeY()

Return value

const char * getRasterTypeName(int num)

Arguments

• int num - Raster band number.

Return value

const char * getRasterUnitType(int num)

Arguments

• int num - Raster band number.

Return value

double getResolutionX()

Return value

double getResolutionY()

Return value

int getVectorCount()

Return value

int getVectorFieldCount(int num)

Arguments

• int num - Layer index in the vector dataset.

Return value

const char * getVectorFieldName(int num, int field)

Arguments

• int num - Layer index in the vector dataset.
• int field - Field definition index.

Return value

Variable getVectorFieldValue(int num, int field)

Arguments

• int num - Layer index in the vector dataset.
• int field - Field definition index.

Return value

const char * getVectorName(int num)

Arguments

• int num - Layer index in the vector dataset.

Return value

int getVectorSurfaceCount(int num)

Arguments

• int num - Layer index in the vector dataset.

Return value

Math::dvec3 getVectorSurfacePoint(int num, int surface, int point)

Arguments

• int num - Layer index in vector dataset.
• int surface - Surface index from which to get point coordinates.
• int point - Surface point index.

Return value

int getVectorSurfacePointCount(int num, int surface)

Arguments

• int num - Layer index in vector dataset.
• int surface - Surface index from which to get points.

Return value

void clear()

int load(const char * name)

Arguments

• const char * name - Dataset name (a path to a file with raster or vector data).

Return value

int vectorFeatureReadNext(int num)

Arguments

• int num - Layer index in vector dataset.

Return value

void vectorFeatureReadReset(int num)

Arguments

• int num - Layer index in vector dataset.