Define Default Raster Scale


 Product(s):MicroStation
 Version(s):N/A
 Environment: N/A
 Area: Raster
 Subarea: N/A
 Original Author:Bentley Technical Support Group

 

 

 

 

 

 

MicroStation provides the MS_RASTER_DEFAULTSCALE configuration variable that attaches rasters at a predetermined scale. The variable is only valid when working with images that are:

 

A quick way to verify this information is to take a peek at the Preview Attachment when attaching an image.

If MS_RASTER_DEFAULTSCALE is undefined or set to 1, then qualifying rasters are attached at a scale of 1 and the pixel size is calculated from the dots per inch (DPI) and set to the appropriate drawing units

So, for example, when an image is attached to a drawing set to FT/IN, it gets a scale of 1 and a pixel size of (1 inch / 300 dots per inch) = 0.0033333 inches or 0.0002778 feet.

 

And, when the same image is attached to a drawing set to M/CM, the scale of 1:1 and a pixel size is calculated as follows: ( 1 inch / 300 dots per inch ) = 0.0033333 inches. This value must then be converted to meters by multiply by 0.0254 to get a final result of 0.00008467 meters.

 

If the variable is set to any whole number other than 1, then that number becomes the scale of the image. For example, setting the variable to 2, will attach the image with a scale of 2.

 

Productivity Tip: To quickly set a variable without editing your configuration files manually, use the EXPAND SET key in as described here: Set Temporary Variables With The Expand Set Keyin. Likewise, to return the value of a variable, use the EXPAND ECHO key in as shown here: Report Your Variables With Expand Echo Keyin.

 

 

And, attaching the same image when the variable is set to 96, will set the scale to 96. 

 

When an image is attached using a scale from MS_RASTER_DEFAULTSCALE, the location of the upper left corner is fixed, while the location of the lower right corner is adjusted. This can be seen in the following graphic where the same image has been attached twice: the smaller one is at a scale of 1 and the larger at a scale of 2. Note that the upper left corner of both images share the same location while the lower right does not.