Since the GIF format utilized the LZW compression technology patented by UNISYS Corporation, MapObjects developers were obligated to establish a licensing agreement with UNISYS before using GIF or TIFF/LZW files as an ImageLayer in their application.
Recently, the UNISYS patent on the LZW technology expired, worldwide. Consequently, it is no longer necessary to request additional licensing from UNISYS, nor complementary keycodes from ESRI.
However, MapObjects versions prior to 2.2 were developed when the keycodes were mandatory and, as such, keycodes are still required when developing with the EnableTIFFLZW and EnableGif methods.
If a MapObjects version at or prior to 2.2 is currently being used, and there has not been a migration to version 2.3, the following license string can be used for unlocking the read capabilities in MapObjects on the Map control to read and display the GIF and TIFF format:
MapObjects 2.2 or higher does not require entering a keycode and these methods have become obsolete. They have remained only for backwards compatibility.
If GIF files need to be created using the Weblink control, refer to the related information below.
What's New in MapObjects 2.2 and 2.3?
MapObjects 2.2 added the following enhancements:
- New Property allowing optional smooth refreshing of the TrackingLayer
- Additional Projection Constants.
- Performance Improvements when loading projected datasets
- Support for the Microsoft .NET Development Environment
- Direct read of GIF / LZW images without license.
MapObjects 2.3 added the following enhancements:
- Now supports ArcSDE 9.0, both as an ArcSDE client, and a direct connect client for Oracle 8i/9i and SQL Server databases. Informix and DB2 databases are also supported as 9.0 direct connect clients.
- Uses the new ArcGIS 9.0 Address Styles for Geocoding.
- Added Improvements to multipoint shape labeling, to parallel the behavior in ArcGIS.
- Added improvements reading CADRG files.
- Added improvements to projection engine performance.