VIEWING MAPS USING THE NATMAP RASTER VIEWER

EXPORT ENTIRE MAP OR CURRENT VIEW

This option allows you to save either the entire current map sheet or the current map view as an image file. A range of image formats are supported: JPEG, BMP, PNG, TIFF and GeoTIFF. You may also export to ECW format when exporting the current view (however there is a bug with ECW exporting). Selecting Export Current View will save only the portion of the map that is currently visible.

1. To export an image, click on the appropriate button in the left hand side panel.
   
2. You will be presented with a standard Save As window where you can enter the name of the image file you wish to create, and select the format in which the image is to be saved. For example :




Once you have entered the name of the image you want to create and selected the type of file, click on the Save button.

3. If the image is being saved in TIFF format you will be presented with the following window asking you to select either TIFF format or GeoTIFF format, and whether you wish to use LZW compression.




Select which TIFF format and compression you require and click on OK.

4. You will then be presented with a window asking for the required resolution of the output image.




Select or enter the output resolution you require and click on OK. Depending upon the size of the image, you may get a warning pop-up (see below).

Limitations on exporting

If you are exporting an entire image from the Mapsheets product or a large region from the Mosaic product, maintaining the original resolution (100%) will require significant amounts of memory (~40Mb) and may take over 30 minutes to complete. Also, depending on the output format, very large image files (30 to 100Mb) may be produced.

You also cannot export areas that are larger than about 10000x10000 pixels - the actual figure depends upon your computer. Computers with very large RAMs may be able to export slightly larger files than this. If you attempt to export an area larger than this figure, you will get the following warning message:

You may also get a virtual memory warning as well as this error.

In general, exporting areas of this size is done most reliably with TIFF/GeoTIFF format - exporting to other formats at this size may crash your system.

Exporting the current view as an ECW file has a 700Mb output limit.

If you want to export larger areas than this, you will either need to export smaller areas and join them together, or use other software. (Free software such as ER Viewer is available from the Downloads page on the ER Mapper website.)

Note on exporting high resolution map images

NATMAP Raster map images have a resolution of 200dpi. (The size of a pixel on the ground in metres varies with your location in Australia.) This resolution was chosen as a compromise between image quality and size so that all map images could fit onto 2 CDs.

The RasterExport and RasterConvert utilities can export map images up to 100% of their original size. These utilities cannot increase the resolution of the output image and any compression artefacts existing in the ECW file will also exist in any exported file.

A user could increase the resolution of an exported image in another software package; however, this would just produce a very big file with no improvement in image quality.

If you want to produce a higher resolution image, then you should contact the Copyright officer.