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guide:help:mnufileexporttoimage

Export to image

Documentation | Help File | UI | 2D Mode | Menu | File | Export to image

Clicking on the File/Export to image menu item provides the means for creating a new image (and digital elevation / grid) file in a number of supported formats. The export is generated from the current map project i.e. from all open layers - so an exported image can be generated from just one layer or from many layers. The image is exported in the Map area coordinate system, so this feature is appropriate for converting images between coordinate systems. Because the image export is size unlimited, the File/Export to image function can be used to mosaic multiple layers into a single image file.

To maximize compatibility with non-TatukGIS software programs, the Editor saves the coordinate system information for an exported image:

  • Embedded natively into the layer, when possible. (Examples: GeoTIFF, PixelStore.)
  • To a PRJ file with the same name as the image file but the *.prj name extension.
  • To a World File with the same name as the image file but with the name extension: ¬†*.tfw for a TIF image, *.pgw for a PNG image, *.bpw for a BMP image, *.jgw or *.jfw for a JPG image.
  • To a TAB registration file (used by MapInfo software products) with the same name as the image file but the *.tab name extension.

PRJ, TAB, and World Files are saved to the same file folder as the exported image file.

To export any extent of the current project as an image file

  1. [OPTIONAL] The Export to image feature gives a possibility to export the extent visible within the Map area by choosing the Select extent/Visible option later in this procedure. To take  advantage of this option, adjust the extent visible within the Map area using the Zoom mode, Zoom extended mode and Drag mode features.
  2. Click on the File/Export to image menu item - this invokes the Save As dialog box.
  3. Within the Save As dialog box, go to the drive on which you want to store the image.
  4. Enter the folder in which you want to save the image.
  5. Enter a name for the image file in the File name field.
  6. Choose the image file format from the Save as type list.
  7. Click on the Save button - this invokes the Export to [chosen format] dialog box, where the chosen format is the format selected in the Save as type list in the previous step.
  8. The Export to [chosen format] dialog box allows to adjust the image parameters: level of compression (Compression box), resolution (Resolution box) and extent to export (Select extent box).
  9. Click on the Save button.


Export to (file format) dialog box. Selected settings to export the full map extent to a high-quality JPEG image file.

Associated functions

  • To export from a vector layer to create a new vector layer file, use the Export function.

Export dialog box settings

  • The Compression box together with the Resolution box provide the quality vs. file size settings. While the resolution setting affects the physical size of the image, the level of compression defines the precision to which the exported image reflects the actual data. The higher the compression level, the smaller the exported file.
  • The Resolution options (which influences the export file size) present a choice of three predefined resolutions: best quality (if the source data is vector, this setting sets a width of 4,000 pixels), for document (300 DPI with a width of 14 cm), and for web (600 pixels in the width). The fourth Resolution option is custom, which allows the user to custom define the export width, height, and DPI (dots per inch).
  • The Select extent settings are used to define the extent of the source map to be exported. The extent options are Full (the exported image is to be generated from the entire map extent), Visible (the export is generated only from the currently visible extent), User defined (the export extend is defined by entering coordinate values to define the top, bottom, right, and left limits of the extent), and Spatial selection (active only if a spatial selection has been performed on a vector layer using any of the spatial selection tools before invoking the Export to image feature. The spatial selection tools are: Select by Polygon, Select by Circle, Select by Rectangle, Select by Clipboard.

Notes

  • Before starting the export operation, the program presents an estimate of the export image size size after considering the export extent, resolution, number of colors (bit depth), and other factors. The estimate does not consider any compression that may be applied during the export operation. (So the final exported image file, with compression, can be smaller than the size estimate.) The size estimate is displayed at the bottom of the Export to [image format] dialog box.
  • Because of inherent size limitations of the JPEG and PNG formats, exporting more than 25 MB of data (before compression) to these formats is generally not recommended. Excessively sized JPEG or PNG files can be unstable and/or not open properly in some software programs. For very large image layers, consider exporting to a TIFF file or a TatukGIS PixelStore database layer (which can efficiently handle even very huge raster layers).
  • Because the export operation is size unlimited, an export operation can involve writing a huge amount of data to the export file. Be patient if exporting a huge image.
  • The image export is generated to the map area coordinate system. To export an image to a different coordinate system, first open the image alone in the Editor and use the Coordinate Systems feature to set the map area to the desired coordinate system. Then use the File/Export to image feature to export the image.
2018/09/13 17:28

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