The result is an essentially real-time, topological 2.5D mapping and database capability. This step is viewed as vital to an efficient, long-term data maintenance and update programme. Integrating IP with DPW adds a 3-D data perspective and enhances the value of the information. The approach may also facilitate the generation of more accurate 3-D vector data in the DPW from features that were not identifiable in the unprocessed imagery. In the event of a crisis, mapping is needed by aid workers within the first critical hours.
Imagery is also a devourer of disk space.
One answer to both problems is to be found in Earth Resource Mapping's ECW compression technology. This allows imagery to be viewed at full resolution, but stored as a file that is many times smaller than its uncompressed alter ego. In this respect, one has to consider the trade-off to be made between highly intuitive user interfaces and the constraints these may impose on system versatility and power. Aside from basic technical issues, one also has to consider data and access standards, copyright, cost, security, data sensitivity, and liability if the data proves to be unreliable. Nonetheless, data providers are turning their attention to standards, and to some form a vital core to the OGC Web Mapping Testbed.