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useful end products. Custom dialog boxes and buttons can be 
designed to provide access to these new scripts. With the 
effects of global change still under debate, the faster the 
information is available, the faster solutions can be proposed 
and legislation implemented. 
Since the GIS userbase is expanding so rapidly, it is not 
feasible to expect vendors to have software particular to every 
application. Software packages must include a way for users 
to incorporate their own functions with a toolkit. The ERDAS 
Software Toolkit, developed under the Version 7 series, 
enabled users to write new application programs to solve 
problems specific to their discipline. Some of these programs 
were later incorporated into the standard ERDAS package. 
ERDAS continues to encourage user interaction with 
IMAGINE. Along with the ERDAS Macro Language Script 
Builder for customizing the interface and grouping processes, 
the C Programmer's Toolkit allows users to write entirely 
new functions. 
PLANNING FOR THE FUTURE 
The continued success of GIS depends on open 
communication lines between vendors, users and data 
suppliers. Users have a responsibility to let vendors know 
what functions they need and vendors have a responsibility to 
meet those needs in a timely fashion and at prices that are 
within reach. Data suppliers are obligated to provide accurate 
and complete data sets that are compatible with other GIS 
layers. To save time and energy, data and software standards 
need to be set. 
Data Standards 
With the growth of GIS and the expansion of application 
areas there is a need for more types of data. Previously, 16- 
bit unsigned integer data were the standard. Now, 32-bit 
signed and unsigned integer data with real and complex 
values are available. This allows greater dynamic range and 
precision of analysis. ERDAS has anticipated the growing 
need for increased precision and has provided 32-bit file 
capability in ERDAS IMAGINE. Satellite imagery, raster and 
vector data, demographic information, spreadsheet data, and 
many other data types that currently exist or are being 
developed, need to be integrated on a single system quickly 
and easily. 
If many data types are required for a study, how easy, or 
how difficult, is it going to be to incorporate them into one 
system? Many software vendors have several conversion 
routines for the most popular data types such as ARC/INFO, 
AutoCAD, DLG, ERDAS, SIF, SPANS and a host of other 
data formats. As more GIS companies are formed and more 
data formats are developed, the job of writing conversion 
routines will become enormous. Vendors, users and 
government organizations must work together. If valuable 
time is spent on transferring data from one system to another, 
there is less time for the actual analysis. ” 
Perhaps a single conversion standard would eliminate the 
need for numerous conversion programs. The U.S. 
Geological Survey is developing a Spatial Data Transfer 
Standard (SDTS) to help curb the need for each software 
vendor to write data transfer routines for each data type they 
want to import or export. SDTS has been submitted for 
approval to the National Institute of Standards and 
Technology. If approved and implemented, SDTS will 
facilitate the transfer of all GIS data-raster, vector, attribute . 
and ancillary data. It will ensure data integrity by recording 
and transferring the data's lineage, positional accuracy, 
attribute accuracy, logical consistency and completeness. The 
proposed standard also addresses the user's need to transfer 
data on many types of media, and to add new types of spatial 
data in the future. 
901 
There is also the issue of standards and benchmarks for 
processing speed and GIS components. Fair and accurate 
measures of GIS software must be developed to make GIS 
technology accessible and understandable to the increasing 
number of generalist users. With equitable standards, it 
would be possible to confidently shop for the best GIS for a 
particular application. 
CONCLUSION 
The technology already exists for true geographic 
visualization. But technology is not enough. Users must be 
able to access this technology in real-world situations. They 
must have hardware and software that is easy to use and that 
provides solutions to the problems they face. They must be 
able to interact with the system and to update their 
information as time, conditions and parameters change. These 
are exciting times to be involved in the GIS industry. The 
applications for this very visual science and art is expanding 
almost daily. GIS has the potential to help solve some 
extremely crucial and earth-threatening problems: global 
warming, deforestation, erosion, housing shortages-this list 
goes on and on. Users, vendors and government agencies 
must communicate with each other and go forward together to 
create the map of the future.