GDAL images

Functions
bool	Image._pushSchemetkRaster (GridColorScheme cScheme)
	Sets color scheme to use in process of generation of the image representation of the grid.
void	Image.BufferToProjection (int BufferX, int BufferY, out double projX, out double projY)
	Converts the position of pixel in image buffer to the map coordinates.
bool	Image.BuildOverviews (tkGDALResamplingMethod ResamplingMethod, int NumOverviews, Array OverviewList)
	Builds overviews for GDAL image.
bool	Image.LoadBuffer (double maxBufferSize)
	Loads the whole image in the memory buffer of specified size. Applicable for GDAL images only.
void	Image.SetNoDataValue (double Value, ref bool Result)
	Sets no-data value for the image. Applicable for GDAL images only.
void	Image.SetVisibleExtents (double newMinX, double newMinY, double newMaxX, double newMaxY, int newPixelsInView, float transPercent)
	Reloads the image buffer to represent the specified map extents. Applicable for GDAL images only.
Properties
bool	Image.AllowHillshade [get, set]
	Indicate whether hillshade algorithm will be used for generation of image representation of the grid.
int	Image.BufferSize [get, set]
	Gets or sets the size of image buffer in percents.
bool	Image.ClearGDALCache [get, set]
	Clears the cache of GDAL library which can be used for faster display.
bool	Image.HasColorTable [get]
	Returns a boolean value which indicates whether an image has a color table. Applicable for GDAL images only.
PredefinedColorScheme	Image.ImageColorScheme [get, set]
	Gets or sets the predefined color scheme for the image. Applicable for GDAL images only.
int	Image.NoBands [get]
	Returns the nubmer of bands of GDAL image.
int	Image.NumOverviews [get]
	Returns the number of overviews for GDAL image.
string	Image.PaletteInterpretation [get]
	Gets the type of pallete interpretation. Applicable for GDAL images only.
bool	Image.UseHistogram [get, set]
	Gets or sets a boolean value which indicates whether a histogram will be used. Aplicable for GDAL images only.

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Detailed Description

Here is a list of methods and properties that are specific for images accessed through GDAL library. The properties and methods described here belong to Image class.

Graph description

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Function Documentation

bool Image._pushSchemetkRaster

(

GridColorScheme

cScheme

)

Sets color scheme to use in process of generation of the image representation of the grid.

Parameters:

cScheme

The color scheme.

Returns:

True on success and false otherwise.

void Image.BufferToProjection	(	int	BufferX,
		int	BufferY,
		out double	projX,
		out double	projY
	)

Converts the position of pixel in image buffer to the map coordinates.

Parameters:

BufferX	The x coordinate of the pixel.
BufferY	The y coordinate of the pixel.
projX	The resulting x coordinate of the map.
projY	The resulting y coordinate of the map.

New API 4.8:

Added in version 4.8

bool Image.BuildOverviews	(	tkGDALResamplingMethod	ResamplingMethod,
		int	NumOverviews,
		Array	OverviewList
	)

Builds overviews for GDAL image.

Overviews are the images with lower resolution which are used as a replacement for the original image while drawing it at small scales. The usage of overviews can significantly improve performance and is highly recommended for large images.

Parameters:

ResamplingMethod	The resamling method to use for generation of the image with lower resolution.
NumOverviews	The number of overviews. Should be equal to the size of OverviewList.
OverviewList	An array of integer type with the specification of overviews (magnification ratios).

Returns:

True on success and false otherwise.

New API 4.8:

Added in version 4.8

bool Image.LoadBuffer

(

double

maxBufferSize

)

Loads the whole image in the memory buffer of specified size. Applicable for GDAL images only.

If the buffer size is smaller than image disk size, the image will be resampled, by decreasing it's linear dimensions by 2.

Parameters:

maxBufferSize

The maximum size of buffer in MB.

Returns:

True on successful loading and false otherwise.

New API 4.8:

Added in version 4.8

void Image.SetNoDataValue	(	double	Value,
		ref bool	Result
	)

Sets no-data value for the image. Applicable for GDAL images only.

The pixels with this value will be treated as transparent.

Parameters:

Value	The value to be set.
Result	A boolean output value which indicates the success of the operation.

New API 4.8:

Added in version 4.8

void Image.SetVisibleExtents	(	double	newMinX,
		double	newMinY,
		double	newMaxX,
		double	newMaxY,
		int	newPixelsInView,
		float	transPercent
	)

Reloads the image buffer to represent the specified map extents. Applicable for GDAL images only.

In most cases the method must not be called directly, as MapWinGIS reloads the buffers for the images automatically after zooming operations.

Parameters:

newMinX	The minimal x coordinate of the new extents.
newMinY	The minimal y coordinate of the new extents.
newMaxX	The maximum x coordinate of the new extents.
newMaxY	The maximum y coordinate of the new extents.
newPixelsInView	The nubmer of image pixels which fall into the specified extents.
transPercent	This parameter is no longer used.

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Properties

bool Image.AllowHillshade [get, set]

Indicate whether hillshade algorithm will be used for generation of image representation of the grid.

int Image.BufferSize [get, set]

Gets or sets the size of image buffer in percents.

The values less than 100 will increase performace of drawing at the cost of decreasing the visual quality.

bool Image.ClearGDALCache [get, set]

Clears the cache of GDAL library which can be used for faster display.

New API 4.8:

Added in version 4.8

bool Image.HasColorTable [get]

Returns a boolean value which indicates whether an image has a color table. Applicable for GDAL images only.

PredefinedColorScheme Image.ImageColorScheme [get, set]

Gets or sets the predefined color scheme for the image. Applicable for GDAL images only.

The color scheme is used for generation of image representation of the grid.

int Image.NoBands [get]

Returns the nubmer of bands of GDAL image.

int Image.NumOverviews [get]

Returns the number of overviews for GDAL image.

See also:

Image.BuildOverviews.

New API 4.8:

Added in version 4.8

string Image.PaletteInterpretation [get]

Gets the type of pallete interpretation. Applicable for GDAL images only.

The possible values are

• "Grayscale";
• "Red, Green, Blue and Alpha";
• "Cyan, Magenta, Yellow and Black";
• "Hue, Lightness and Saturation";
• "Unknown".

bool Image.UseHistogram [get, set]

Gets or sets a boolean value which indicates whether a histogram will be used. Aplicable for GDAL images only.