ECW

Enhanced Compressed Wavelet (ECW) is a popular standard for compressing and using very large images. ECW is a proprietary, patented format developed by Hexagon Geospatial.

From Global Mapper, any loaded raster, vector, and elevation grid data sets can be exported to an ECW file. ECW files are highly compressed and great for storing data such as satellite imagery. There is no size restriction on exported ECW files, so it's possible to store many terabytes worth of imagery within a single highly compressed ECW file.

When selected, the command displays the ECW Export Options dialog which allows the user to setup the export.

Target Compression

To generate an uncompressed format file, simply slide the Target Compression Ratio slider all the way to the left (1:1 target compression ratio).

A compression ratio expresses the file-size differences between the original image and compressed image. A compression ratio of 2:1 means the original image was reduced by a factor of 2.

Band Setup

  • Default RGB Layout- This option generates a 3 band RGB ECW with 8-bits per band
  • Grayscale- This option generates a 1 band image with 256 scales of gray ranging from black to white.

Metadata File Formats to Generate

Select any additional metadata or projection files to be produced with the ECW export.

ECW Format Version

Choose to export the file as ECW v2 or v3. The default behavior is as follows:

  • Data with 8-bit samples will default to ECW v2 for maximum compatibility with other software that may not support v3.
  • High bit depth exports will default to ECW v3.

Other Options:

Save Map Layout

The distance scale, elevation legend, and coordinate grid will be saved to the file (except when exporting elevation grids) if they are configured to show up in the main display.

Save Vector Data if Displayed

Any loaded vector data that is configured to show up in the main display will be saved to the image file (except when exporting elevation grids).

Interpolate to fill small gaps in data

Any small areas with missing data will be filled in by interpolating the surrounding valid data using an IDW method. This is useful for filling small gaps between adjacent tiles or small holes in elevation data.

Make Background (Void) Pixels Transparent:

An alpha channel will be added to the file to indicate which pixels should be treated as transparent.

Include Projection/Datum in Header

The projection information will be saved to the ECW header.

Save ECW Projection Name as EPSG:XXXX

The projection and datum name saved in the ECW header will be formatted as ESPG:XXXX

 

Format Updates

Version Description
26.2 ERDAS ECW JP2 SDK update to v6.1. Supports ECW v3 exports.