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A geometric spatial reliability diagram should indicate the sources 
from which the final thematic map was compiled and which parts 
of the data can be considered reliable based on an established 
accuracy standard (e.g. National Map Accuracy Standards). For 
example, Figure 4 depicts a geometric reliability diagram where 
a thematic map has been compiled from SPOT panchromatic data, 
from USGS digital line graph (DLG) transportation data, and a 
USGS digital elevation model (DEM) containing "good" and "bad" 
data. It is evident that the geometric reliability of such data 
sources is clearly stated in the legend. The legend also identifies 
that the DLG vector data were converted to raster format and 
resampled to 10 x 10 m. Additional information such as the root 
mean square error (RMSE) associated with the resampling 
procedures of each data set can also be included. This type of 
annotation helps readers identify portions of the final thematic 
map which have reduced geometric reliability and can be useful 
for improved decision making. It need not be present on the map, 
but should be easily accessible on the system by the user. 
Most modern mapping applications utilize thematic data obtained 
on different dates and/or at different minimum mapping units. 
Although a final map may look uniform in its accuracy, it is 
actually an assemblage of thematic information from diverse 
sources which vary in accuracy. Newcomer and Szajgin (1984) 
and Walsh et al. (1987) suggest that the highest accuracy of any 
GIS output product is only as accurate as the least accurate file 
used in its creation. It is important for the reader to know the 
source of the error by depicting them in a thematic reliability 
diagram. The thematic reliability diagram shown in Figure 5 
identifies two sources of data used in a supervised classification 
of wetlands and the location of in situ samples used to assess map 
accuracy. Scientists who map wetlands might be concerned that 
only DLG wetland data were used. Also, the diagram reveals that 
the in situ sampling was spatially biased toward locations which 
were accessible only by boat. These two facts can help a reader 
to determine the value of a thematic map product derived from the 
application of various techniques. 
When developing digital geometric and thematic reliability 
diagrams, there is a need to standardize their design and function. 
The most common questions pertain to the information content 
and the amount of detail presented on such diagrams. First, the 
diagrams should contain information on the data source (e.g. 
USGS 1:24,000 topographic quad). Second, the date of the 
original compilation of source data and the dates of subsequent 
updates should be included. Third, details on the spatial resolution 
to which the data may have been resampled (e.g. 10 x 10 m 
resampling of a Landsat TM scene) should be clearly stated. 
Fourth, the reliability diagrams must indicate the areas which 
would be considered "bad" data, or more specifically data that do 
not conform to some accepted accuracy standards. Fifth, if in situ 
data is used, then the bias or limitations in the acquisition of such 
measurements, such as the number of sample points used or the 
restricted access to parts of a study area should be shown. 
By including this information in geometric and thematic reliability 
diagrams a reader is made aware of the overall accuracy of the 
final map. It will also limit the liability of the producers of such 
maps, and increase the public confidence in the integrity of 
products from the remote sensing and GIS community. 
LINEAGE (GENEALOGY) OF THEMATIC MAPS 
AND IMAGE MAPS 
It is important to identify the difference between lineage and 
spatial reliability diagrams. Lineage documentation records the 
entire history of all analytical operations performed on a dataset, 
and its resultant products. For example, Chrisman (1983) defined 
"lineage" as the documentation of data sources and transformations 
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[iterations] applied to them. Conversely, the spatial reliability 
diagrams previously discussed provide details on the sources used 
in the compilation of the ‘final product’. 
Remote sensing and GIS final products are produced from basic 
source materials. Manual "book-keeping" of the processes used 
for deriving the final product is cumbersome and rarely performed. 
There are systems which provide automated methods such as 
‘history’ or ‘audit’ files to keep track of the iterations and 
operations performed. However, none of these methods are 
capable of fulfilling the informational requirements of a true 
‘lineage’ report which itemizes the characteristics of image and 
cartographic sources, the topological relationships between source, 
intermediate and final product layers, and the transformations 
applied to sources to derive the output products (Lanter, 1990). 
The National Committee for Digital Cartographic Data Standards 
(NCDCDS) proposed that lineage information be included in every 
*quality report' of a digital cartographic product (NCDCDS, 1988). 
The committee specified five requirements for the lineage criteria, 
including: 
a) source material from which the data were derived; 
b) methods of derivation, including transformations 
applied; 
c) if data from different distinct sources are used, such 
sources must be identified; 
d) include reference to specific control information used, 
e.g. National Geodetic Reference System or if other 
points are used then sufficient detail must be 
provided to allow recovery; and 
e) description of the mathematical transformations of 
coordinates used in each step from source material 
to final product. 
Lanter (1991) categorized geographic data layers into source 
layers, intermediate layers, and product layers. ^ Lineage 
information on source layers should include the NCDCDS digital 
cartographic data standards, while intermediate layers require 
documentation on the nature of the transformations used in their 
derivation. Final product layers must be associated with 
information concerning their use, such as the users' role in 
decision making, release dates, and those responsible for product- 
layer maintenance (Lanter, 1990). 
Lineage or genealogical documentation should, therefore, form an 
integral part of the annotation of remote sensing or GIS products. 
Software designed to document lineage must have the following 
components: 1) lineage tracing, 2) maintain data quality 
information, 3) automatic error detection, 4) rule building (i.e. 
flexibility to users on building their own rules into a knowledge 
base about how their GIS data should be handled), 5) data-driven 
user interface, and 6) project management (such as keeping track 
of times, dates, and user names to show who did what to the 
database and when) (Lanter, 1989). This will resolve data 
management problems by maintaining an automated, dynamic 
model of the database. In addition, the user will have information 
on cartographic materials used and a chronicle of the remote 
sensing or GIS transformations applied to derive the final 
products. In most cases it may only be necessary to explicitly 
state in a textual legend a) the name of the lineage file, e.g. 
Jensen.21092, and b) the cognizant scientist (and his/her address) 
who was responsible for creating the final product. The lineage 
file must then accompany the final product file. 
CONCLUSION 
Remote sensing and GIS products will be cartographically 
enhanced by adopting the five types of annotation discussed in this 
paper. It is also important for the image processing and GIS