Grid

A Grid item is an item that is displayed as a raster image, depicting 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.

Properties

• Bitmap file
• Bitmap type
• Colour depth
• Colour-set
• Compression
• Grid value resolution
• Height
• Maximum grid value
• Minimum grid value
• No-data grid value
• No-data value
• Resample method
• Resolution
• Transparent
• Use no-data value
• Width
  

Item Properties

Properties

• 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.
  
  
• Colour-set: _colourset$
  The Colour-set 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.
  

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