TGIS_LayerPixel class

DK for Delphi | GisLayerPixel.TGIS_LayerPixel | Classes | Constructors | Fields | Methods | Properties | Events

Abstract base class for georeferenced pixel and raster layers, providing shared bitmap and numeric grid infrastructure.

Available also on: .NET | Java | ActiveX | Python.

// Delphi
type
  TGIS_LayerPixel = class( TGIS_Layer )
  end;

// C++ Builder
class PASCALIMPLEMENTATION TGIS_LayerPixel : public TGIS_Layer
{
};

→ TGIS_BaseObjectDisposable → TGIS_LayerAbstract → TGIS_Layer

For specifying some more advanced pixel layer appearances, such as color mapping, transparent zones, etc., the property Pixel.Params should be used.

For properties, such as: RedMapZones, BlueMapZones, GreenMapZones, it is possible to create a section for different values zones:

lp.Params.Pixel.RedMapZones.Add("1, 100, 0, 127"); 
lp.Params.Pixel.RedMapZones.Add("200, 100, 127, 255"); 

The general format is:

"start_value,end_value,start_value_mapped,end_value_mapped"

Where:

• start_value
  is the starting value of a zone expressed in native layer values (so for 16-bit layers it can be above 255);
• end_value
  is a the end value of a zone expressed in native layer values (so for 16-bit layers can be above 255);
• start_value_mapped
  is the starting value of a zone expressed as a RGB channel value (0..255);
• end_value_mapped
  is the end value of a zone expressed as a RGB channel value (0..255).

Values between the start_value and end_value will be smoothly mapped to values between the start_value_mapped and end_value_mapped. start_value_mapped can be smaller then end_value_mapped to achieve inversion.

Accepted values are integer, like 37 or hexadecimal like $25.

FullRGB zones are used to map one color to another.

lp.Params.Pixel.RedMapZones.Add("$EFEFEF, $FFFFFF, $00FF00"); 
lp.Params.Pixel.RedMapZones.Add("$000000, $0F0F0F, $0000FF"); 

The general format is:

"start_color,end_color,mapped_color"

Where:

• start_color
  is the starting color expressed as a RGB value;
• end_color
  is the end color expressed as a RGB value;
• mapped_color
  is the mapped color expressed as a RGB value.

If a color is between the start_color and end_color, then it will be mapped to a mapped_color.

The operation “between” is done per channel. So, construction between $102030 and $A0B0C0 means that any color with R:$10..$A0, G:$20..$B0 and B:$30..$C0 will be mapped. This can be used, for example, to match any color that is close to white to another color.

Accepted color values are RGB integer, like 255, hexadecimal like $0000FF, R:G:B like 0:0:255, or using names: AQUA, BLACK, BLUE, FUCHSIA, GRAY, GREEN, LIME, MAROON, NAVY, OLIVE, PURPLE, RED, SILVER, TEAL, WHITE and YELLOW.

If the last provided parameter is BGR, like $112233,$AABBCCF,BGR, then the color will be interpreted as BGR, not RGB.

Gray zones are used to map gray to color:

lp.Params.Pixel.GrayMapZones.Add("0, 127, $0000A0, $0000FF"); 
lp.Params.Pixel.GrayMapZones.Add("127, 255, $A00000, $FF0000FF"); 

The general format is:

"start_value, end_value, start_color, end_color"

Where:

• start_value
  is the starting value of a gray-scale image (0..255);
• end_value
  is a the end value of a gray-scale image (0..255);
• start_color
  is the starting color expressed as a RGB value;
• end_color
  is the end color expressed as a RGB value.

Values between the start_value and end_value will be smoothly mapped to values between the start_color and endcolor. start_value can be smaller then the end_value to achieve an inversion.

The operation “between” is done per channel. So construction between $102030 and $A0B0C0 means that any color with R:$10..$A0, G:$20..$B0 and B:$30..$C0 will be mapped.

Accepted color values are RGB integer like 255, hexadecimal like $0000FF, R:G:B like 0:0:255, or names: AQUA, BLACK, BLUE, FUCHSIA, GRAY, GREEN, LIME, MAROON, NAVY, OLIVE, PURPLE, RED, SILVER, TEAL, WHITE and YELLOW.

If the last provided parameter is BGR, like $112233, $AABBCCF, BGR, the color will be interpreted as BGR, not RGB.

Transparency zones are used to define which color should be transparent:

lp.Params.Pixel.TransparentZones.Add("$EFEFEF, $FFFFFF"); 
lp.Params.Pixel.TransparentZones.Add("$000000, $0F0F0F"); 

The general format is:

"start_color, end_color"

Where:

• start_color
  is the starting color expressed as a RGB value;
• end_color
  is the end color expressed as a RGB value;

If color is between the start_color and end_color, it will be mapped as transparent.

This operation “between” is done per channel. So construction between $102030 and $A0B0C0 means that any color with R:$10..$A0, G:$20..$B0 and B:$30..$C0 will be mapped. This can be used, for example, to match any color that is close to white to transparent.

Accepted color values are RGB integer like 255, hexadecimal like $0000FF, R:G:B like 0:0:255, or names: AQUA, BLACK, BLUE, FUCHSIA, GRAY, GREEN, LIME, MAROON, NAVY, OLIVE, PURPLE, RED, SILVER, TEAL, WHITE and YELLOW.

If the last provided parameter is BGR, like $112233, $AABBCCF, BGR, then the color will be interpreted as BGR, not RGB.

Altitude zones are used to apply grid layer coloring:

lp.Params.Pixel.AltitudeMapZones.Add("100.45, 800.12, $FF0000"); 
lp.Params.Pixel.AltitudeMapZones.Add("800.12, 900.45, $FFFF00"); 

The general format is:

"start_value, end_value, color"

Where:

1. start_value
   is the starting value of the zone expressed in native layer values;
2. end_value
   is the end value of the zone expressed in native layer values;
3. color
   is the RGB value representing the zone color.

Accepted grid values are float values with dot decimal point, like “123.45”.

Accepted color values are RGB integer like 255, hexadecimal like $0000FF, R:G:B like 0:0:255, or names: AQUA, BLACK, BLUE, FUCHSIA, GRAY, GREEN, LIME, MAROON, NAVY, OLIVE, PURPLE, RED, SILVER, TEAL, WHITE and YELLOW.

If the last provided parameter is BGR, like $112233, $AABBCCF, BGR then the color will be interpreted as BGR, not RGB.

1. Selecting which channel will be used to form RGB.
2. Mapping native layer values to 0..255 (RGB) zone with the use of RedMapZones, GreenMapZones, and BlueMapZones, if any of these exists.
3. Mapping color-to-color, if FullRGMMapZones exits.
4. Firing event for additional custom color mapping.
5. Applying TransparentZoneMaps, if any exists.
6. Making grayscale, if requested.
7. Applying GreyScaleZones, if any exist.
8. Applying histogram correction, if requested.
9. Applying brightness, contrast, inverse, and RGB channel value modifications.

1. Selecting which channel will be used as the grid source.
2. Applying AltitudeMapZones, if these exist; if not, perform simple mapping to a grayscale image.

All properties of Params.Pixel are available as: TGIS_ParamsPixel class.

Available metadata keys:

• CuttingPolygon sample
• ExportToImage sample
• Grid sample
• Interpolation sample
• JupyterNotebookDKForPython sample
• JupyterNotebookPythonAndNumpy sample
• PixelEdit sample
• PixelOperations sample
• Viewer sample