Exporting to a 24-bit Colour BMP

Transcription

1 Importing a BMP Exporting to a 24-bit Colour BMP File Type: BMP (Windows Bitmap) Directions: BMP<->MF Details: BMP (Windows Bitmap) is a standard graphic file format for Windows and DOS based platforms. The MFworks BMP import translator will accept only uncompressed Windows BMP files. This translator accepts greyscale images (1, 2, 4, or 8-bits deep), paletted colour images (1, 2, 4, or 8-bits deep), or full colour images (24-bits deep). The values in the legend will be either the palette/greyscale index number, or the actual 16-bit colour expressed numerically (0 high bit and 3 groups of 5-bit colour information for the red, green, and blue channels). Importing a BMP RED GREEN BLUE When you export to a Bitmap file, any cells with the value ÒVOIDÓ will be assigned the colour that you have assigned to that zone in the map layer. MFworks exports BMP files uncompressed. Import Dialog Using the translator dialog box interface None. TR-BMP-1

2 Import Syntax Syntax and type conventions Using the Script window interface Import input file Using "BMP (Bitmap)"; Import Example Importing a BMP A portion of a Canada National Topographic System (NTS) paper topographic map is scanned in 16-bit colour on a flat-bed scanner and saved as a BMP file: To import this file, select Import Map from the File menu and specify the file from the Import Map dialog box. Specify BMP from the Type dropdown list. If this file were to be imported using the Import command from the Script window the statement would be: "Imported BMP" = Import "paisley.bmp" Using "BMP (Bitmap)"; The resulting file appears exactly as the original BMP file. Zone values are assigned a value representing the actual 16-bit colour expressed numerically TR-BMP-2

3 (0 high bit and 3 groups of 5-bit colour information for the red, green, and blue channels): RED GREEN BLUE An imported scan of a topographic map can be a useful basemap. You can use it to trace contours and generate a DEM (Digital Elevation Model), trace features and generate a land use map layer, or trace rivers and water bodies and generate an hydrology map layer: TR-BMP-3

4 Exporting to a BMP Export Dialog Using the translator dialog box interface Depth Zone colours (32-bit) Use this option to export a map layer as a 32-bit colour image. Depth Zone colours (24-bit) Use this option to export a map layer as a 24-bit colour image. Depth Zone colours (8-bit palette) Use this option to export a map layer as an 8-bit indexed paletted image. 8- bit files occupy only one third the space of the 24-bit file type; however, converting to 8-bit colour may result in a loss of colour accuracy. Export Syntax Syntax and type conventions Using the Script window interface ExportMap map To outputêfile Using "BMP (Bitmap)" [Output32BitColour Output24BitColour Output8BitColour]; Output32BitColour Use this modifier to export a map layer as a 32-bit colour image. TR-BMP-4

5 Output24BitColour Use this modifier to export a map layer as a 24-bit colour image. Output8BitColour Use this modifier to export a map layer as an 8-bit indexed paletted image. 8-bit files occupy only one third the space of the 24-bit file type; however, converting to 8-bit colour may result in a loss of colour accuracy. Export Example Exporting to a 24-bit Colour BMP The following map layer of 1998 Precipitation patterns for Canada is to be exported as a 24-bit colour BMP file to be used as a background for a high end drawing package: The Export Map command is selected from the File menu and BMP is chosen from the Export Map dialog box Type drop-down list. This causes TR-BMP-5

6 the Export Map to BMP File dialog box to be displayed. The Zone colours (24-bit) option is chosen: If you were executing this command from the Script window the statement would be: ExportMap "Canada 1998 Avg Precipitation" To "1998Precip24bit.BMP" Using "BMP (Bitmap)" Output24BitColour; The BMP file that results has the full range of colours of the original map layer preserved. It can be used in many other software applications such as desktop publishing, image processing, GIS, illustration, and drawing packages: TR-BMP-6

7 Error Messages Sorry, the form of compression used within this BMP file is not supported by this translator. Try creating an uncompressed BMP file and import the new file. Sorry, there is not enough memory to load the Bitmap Data. Try closing windows and/or applications to free up more system memory. TR-BMP-7