Using ECW- or JPEG2000-file as a background map. ECW-file is a format (see www.ermapper.com) which reduces the size of memory needed to show a map. Still one ECW-file can be several Gigabytes in size. JPEG2000 is technically similar to ECW, but uses lossless packing. This means that it is more suitable for storing raster maps.
When this function is on, it will show all the files selected in the list. Multiple files can be selected with Shift- or Ctrl-keys. If there is no selection, all files are shown. File order in the list determines the drawing order. Files can be arranged with Alt-arrow keys.
In Tools/More/ECW OnOff you can set ECW-drawing On/Off.
The idea of ECW-files is to have big file to get the fastest result. This function can handle several files at the same time. If you have to user several files, try using at least 500 Mb file size.
Accuracy in the screen. Normally there is an ECW-pixel for every pixel in the screen. You can make the drawing much faster by reducing the accuracy.
1:1 there is an ECW-pixel for every pixel in the screen
1:2 the ECW-file size is only half of the screen size in horizontal and vertical directions. So only one forth of the original normal accuracy.
1:4 the ECW-file size is only half of the screen size in horizontal and vertical directions. So only 1/16 of the original normal accuracy.
Parameter can be given as percentage value. 0 = no brightening, 100 = totally white.
Removing larger black areas. Parameter is given limit value and all darker areas will be removed. 0 = totally black. Practical values are 5-15. Area is removed if there are more than 3 black pixels in a row.
On: picture are updated every time you change zoom.
Off: pictures are not shown, but you can modify the list.
Fix: pictures are shown, but not updated. Pictures are the same as when you set on Fix-mode.
Read the single ECW-files into the list or use a control file having several ECW-files one name per one line. If file name has no path, the control file path will be used. Lines starting with exclamation mark (!) are comment lines.
E.g:
! This is a control file for ECW-files e:\data\ecw\map21.ecw E:\data\ecw\map22.ecw
To remove a file from the list. With Shift-key removes files outside of the screen.
Clear the whole list. With the Shift-key reloads all images from the disk updating possibly changed files. With the Ctrl-key writes file names to control file.
To show all selected ECW-files in the screen.
Hold down Shift-key while selecting Zoom to show all the files in the list.
To start EWC-function automatically in program startup, read the ECW-files in the list and select ECW-function in Settings/Desktop/Start program.
There are some special settings related to this function.
1 use all ECW-files in ZoomAll-function
64 output to paper using screen resolution.
See also: Using special settings