A Grid item is an item that is displayed as a raster image. This can depict a Digital Terrain Model (DTM) or the density of point data.
It is made up of coloured cells, or pixels, the colour corresponding to a numerical value.
This value could be the height above sea level of that cell (a DTM), or the number of burglaries in that area.
- Bitmap file: _bmpfile$
The file containing the Bitmap. Bitmap items which do not use linked files leave this property empty.
- Bitmap type: _classDib$
The type of image this Bitmap item displays.
- Colour depth: _depth&
The number of bits defining each pixel in a Bitmap. The more depth a Bitmap has, the more colours it can show simultaneously.
- Colourset: _colourset$
The Colourset object used by a Grid item. This affects how the Grid item is coloured. If you do not specify a colourset name then the Grid item's Pen colour will be used.
- Compression: _compression#
The compression which has been applied to the Bitmap data. Uncompressed Bitmap items have a compression of 1, and JPEG Bitmap items can have a compression as small as 0.1.
- Grid value resolution: _GridValRes#
The resolution of values in a Grid item. Each cell in a Grid item stores a 16 bit signed integer. The Grid item stores a single floating point multiplier which converts the integer cell values into grid values.
- Height: _height&
The number of rows in the Bitmap item.
- Maximum grid value: _MaxGridVal#
The highest value within a Grid item
- Minimum grid value: _MinGridVal#
The lowest value within a Grid item
- No-data grid value: _NoDataGridVal#
Shows the No-data value (for information only)
- No-data value: _NoData&
Change to set a specific data value to transparent. When a value is entered the Use no-data value is set to True.
- Resample method: _resample&
The method a Bitmap or Grid item uses when pixel values need to be resampled.
- Resolution: _resolution#
The resolution of a Polygon, QZone, or Bitmap item.
For a Polygon item, the value is the resolution of the invisible cached QZone item. If there is no cached QZone item then the Polygon item's resolution is reported as zero.
A QZone item is made up of progressively smaller squares. Its resolution is the size of the smallest QZone square.
The resolution of a Bitmap item is the size of each pixel.
- Transparent: _transparentColour$ /_alphaTransparency&
Is the Bitmap item transparent? If a Bitmap is transparent then any light coloured pixels will not obscure the graphics which are underneath it. Some displays and printers do not fully support transparency.
- Use no-data value: _bNoData&
True uses the No-data value. False resets the No-data value to zero.
- Width: _width&
The number of pixels in each row of a Bitmap.