GdalQuery.ColorFromAttributeTable Property

Gets or sets an attribute variable that will assign colors from a raster attribute table.

Syntax

public AttributeVariable< System.Drawing.Color > ColorFromAttributeTable { get; set; }

Property Value

Type: An attribute variable that returns a value of type System.Drawing.Color.
Default: null
An attribute variable that will assign colors from a raster attribute table.

Remarks

When a thematic raster dataset has a color scheme designed by the data provider, Carmenta Engine will apply the color scheme automatically if it is encoded in the basic data format, for example TIFF.

But sometimes, the color scheme is instead provided as metadata in a raster attribute table stored separately, for example in an Esri-style .vat.dbf file, usually as three columns RED, GREEN and BLUE like this:

VALUE	LAND_COVER	RED	GREEN	BLUE
11	"Open Water"	0.278	0.420	0.627
21	"Residential"	0.670	0.000	0.000
31	"Barren land"	0.698	0.678	0.639
41	"Deciduous Forest"	0.408	0.667	0.388
42	"Evergreen Forest"	0.110	0.388	0.188
43	"Mixed Forest"	0.710	0.788	0.557
51	"Shrubland"	0.800	0.729	0.486
71	"Grasslands"	0.886	0.886	0.757

In that case, Carmenta Engine will not apply the color scheme automatically, but you can apply the color scheme by defining a ColorFromAttributeTable property.

If the RED, GREEN and BLUE columns contain integers in the range 0 to 255, the same range that Carmenta Engine expects, you can construct a ColorFromAttributeTable using a string expression that represents the color:

"rgb(" + string(RED) + "," + string(GREEN) + "," + string(BLUE) + ")"

But if the columns contain Float numbers in the range 0.0 to 1.0 as in the example table, the string expression must rescale them to the 0 — 255 range:

"rgb(" + string(int(255 * RED)) + "," + string(int(255 * GREEN)) + "," + string(int(255 * BLUE)) + ")"

If ColorFromAttributeTable is used and some raster cells contain values that do not occur in the Value column, they will get the transparent color.

Platforms

Windows, Linux, Android

GdalQuery::colorFromAttributeTable Property

Gets or sets an attribute variable that will assign colors from a raster attribute table.

Syntax

C++

public:
ColorAttributeVariablePtr colorFromAttributeTable ( ) const;
void colorFromAttributeTable ( const ColorAttributeVariablePtr& value )

Property Value

Type: An attribute variable that returns a value of type Color.
Default: null
An attribute variable that will assign colors from a raster attribute table.

Remarks

When a thematic raster dataset has a color scheme designed by the data provider, Carmenta Engine will apply the color scheme automatically if it is encoded in the basic data format, for example TIFF.

VALUE	LAND_COVER	RED	GREEN	BLUE
11	"Open Water"	0.278	0.420	0.627
21	"Residential"	0.670	0.000	0.000
31	"Barren land"	0.698	0.678	0.639
41	"Deciduous Forest"	0.408	0.667	0.388
42	"Evergreen Forest"	0.110	0.388	0.188
43	"Mixed Forest"	0.710	0.788	0.557
51	"Shrubland"	0.800	0.729	0.486
71	"Grasslands"	0.886	0.886	0.757

In that case, Carmenta Engine will not apply the color scheme automatically, but you can apply the color scheme by defining a colorFromAttributeTable property.

If the RED, GREEN and BLUE columns contain integers in the range 0 to 255, the same range that Carmenta Engine expects, you can construct a colorFromAttributeTable using a string expression that represents the color:

"rgb(" + string(RED) + "," + string(GREEN) + "," + string(BLUE) + ")"

But if the columns contain Float numbers in the range 0.0 to 1.0 as in the example table, the string expression must rescale them to the 0 — 255 range:

"rgb(" + string(int(255 * RED)) + "," + string(int(255 * GREEN)) + "," + string(int(255 * BLUE)) + ")"

If colorFromAttributeTable is used and some raster cells contain values that do not occur in the Value column, they will get the transparent color.

Platforms

Windows, Linux, Android

GdalQuery.colorFromAttributeTable Property

Gets or sets an attribute variable that will assign colors from a raster attribute table.

Syntax

Java

public final ColorAttributeVariable getColorFromAttributeTable ( );
public final void setColorFromAttributeTable ( ColorAttributeVariable value );

Property Value

Type: An attribute variable that returns a value of type Color.
Default: null
An attribute variable that will assign colors from a raster attribute table.

Remarks

When a thematic raster dataset has a color scheme designed by the data provider, Carmenta Engine will apply the color scheme automatically if it is encoded in the basic data format, for example TIFF.

VALUE	LAND_COVER	RED	GREEN	BLUE
11	"Open Water"	0.278	0.420	0.627
21	"Residential"	0.670	0.000	0.000
31	"Barren land"	0.698	0.678	0.639
41	"Deciduous Forest"	0.408	0.667	0.388
42	"Evergreen Forest"	0.110	0.388	0.188
43	"Mixed Forest"	0.710	0.788	0.557
51	"Shrubland"	0.800	0.729	0.486
71	"Grasslands"	0.886	0.886	0.757

In that case, Carmenta Engine will not apply the color scheme automatically, but you can apply the color scheme by defining a colorFromAttributeTable property.

"rgb(" + string(RED) + "," + string(GREEN) + "," + string(BLUE) + ")"

But if the columns contain Float numbers in the range 0.0 to 1.0 as in the example table, the string expression must rescale them to the 0 — 255 range:

"rgb(" + string(int(255 * RED)) + "," + string(int(255 * GREEN)) + "," + string(int(255 * BLUE)) + ")"

If colorFromAttributeTable is used and some raster cells contain values that do not occur in the Value column, they will get the transparent color.

Platforms

Windows, Linux, Android

GdalQuery.colorFromAttributeTable Property

Gets or sets an attribute variable that will assign colors from a raster attribute table.

Syntax

Python

colorFromAttributeTable

Property Value

Type: An attribute variable that returns a value of type Color.
Default: null
An attribute variable that will assign colors from a raster attribute table.

Remarks

When a thematic raster dataset has a color scheme designed by the data provider, Carmenta Engine will apply the color scheme automatically if it is encoded in the basic data format, for example TIFF.

VALUE	LAND_COVER	RED	GREEN	BLUE
11	"Open Water"	0.278	0.420	0.627
21	"Residential"	0.670	0.000	0.000
31	"Barren land"	0.698	0.678	0.639
41	"Deciduous Forest"	0.408	0.667	0.388
42	"Evergreen Forest"	0.110	0.388	0.188
43	"Mixed Forest"	0.710	0.788	0.557
51	"Shrubland"	0.800	0.729	0.486
71	"Grasslands"	0.886	0.886	0.757

In that case, Carmenta Engine will not apply the color scheme automatically, but you can apply the color scheme by defining a colorFromAttributeTable property.

"rgb(" + string(RED) + "," + string(GREEN) + "," + string(BLUE) + ")"

But if the columns contain Float numbers in the range 0.0 to 1.0 as in the example table, the string expression must rescale them to the 0 — 255 range:

"rgb(" + string(int(255 * RED)) + "," + string(int(255 * GREEN)) + "," + string(int(255 * BLUE)) + ")"

If colorFromAttributeTable is used and some raster cells contain values that do not occur in the Value column, they will get the transparent color.

Platforms

Windows, Linux, Android

GdalQuery.ColorFromAttributeTable Property

In this article

Syntax

Property Value

Remarks

Platforms

See Also

Reference

Other Resources

GdalQuery::colorFromAttributeTable Property

In this article

Syntax

Property Value

Remarks

Platforms

See Also

Reference

Other Resources

GdalQuery.colorFromAttributeTable Property

In this article

Syntax

Property Value

Remarks

Platforms

See Also

Reference

Other Resources

GdalQuery.colorFromAttributeTable Property

In this article

Syntax

Property Value

Remarks

Platforms

See Also

Reference

Other Resources