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a. the ability to transfer vector, raster, grid, and attribute data, and other 
ancillary information. 
b. the implementation methodology can be media-independent and extendable 
to encompass new spatial information as needed. 
c. an internally contained description of the data types, formats, and data 
structures such that the information items can be identified and processed 
into the user’s native system. 
d. the data and media formats should be based where practical on existing 
FIPS, ANSI, ISO, or other accepted standards." 
The Spatial Data Transfer Specification is the method whereby spatial data from one data 
handling system can be easily transferred to another data handling system. The standard 
provides a modular specification of data types and formats for the full set of digital 
information to be transferred. Of necessity, the transfer specification is complex because it 
must handle both vector and raster data. 
Content 
The proposed standard (SDTS Technical Review Board, 1990) consists of three parts. Part 
1, Logical Specifications, includes a conceptual model of spatial data and definitions of 
fundamental cartographic objects and key terms that serve as conceptual building blocks for 
the constructs presented in the standard; a transfer specification, defining the logical file 
structure for the transfer of the data; and data quality requirements that specify the form of 
the quality report and require the data provider to supply detailed information about the 
data set being transferred in order for the user to evaluate the fitness of that data for a 
particular use. The Logical Specification component defines a set of primitive and simple 
cartographic objects in zero, one, and two dimensions with which digital cartographic 
feature representations can be built. Definitions are also presented for key conceptual 
terms that are used throughout the standard. The basic concept underlying the Data 
Quality component is a "truth in labeling" concept. The standard requires a report of what 
is known about the quality of the included data. Five components are available under 
which to define data quality: lineage, positional accuracy, attribute accuracy, logical 
consistency, and completeness. 
Part 2, Spatial Features, presents a domain of cartographic entities and attributes with 
standard definitions, and a list of included terms to facilitate cross referencing from user 
feature categories to standard categories. The Spatial Features component provides a model 
and definitions for cartographic features. The model consists of entities, attributes, and 
attribute values. A list of topographic and hydrographic entities and attributes is provided 
with the standard; however, the standard also provides a mechanism for user-supplied 
definitions to accompany the data transfer. 
Part 3, the ISO Implementation, uses the existing international standard, "Information 
Processing Specification for a Data Descriptive File for Information Interchange," as the 
implementation mechanism for physical encoding of SDTS data.