U.S. Geological Survey Bulletin 2016
Selected Papers in the Applied Computer Sciences 1992

FIGURE CAPTIONS

COVER Cover 1:  Computer-shaded relief image of Italy and the neighboring
seafloor, at 1 km resolution. Land and submarine surfaces are shown
continuously, without the distraction of a coastline. Dark grey areas - data
unavailable. View is about 1000 km across.  Robert Mark and Richard Pike
prepared the map by combining digitized elevations and depths supplied to
the U.S. Geological Survey by the Italian government (see Chapter B). 

Covers 1 and 4: Design and layout by Sunne Rinkus, 1992.

CHAPTER A Figure 1.  A diagrammatic representation of an integrated GIS
linking related surface and subsurface information crucial for evaluating,
assessing, and managing natural resource programs. 

CHAPTER B Figure 1.  General steps in the preparation of a shaded-relief map
(modified from Brassel, 1974, and Horn, 1981). 

Figure 2.  Geometric relation between ground slope and Sun position that is
basic to reflected-intensity (brightness) calculations for shaded-relief
mapping. See equation 1 in text. Height O is center of five-point sample of
digital elevation model (fig.  3) (modified from Batson and others, 1975). 

Figure 3.  Measuring aspect and slope of a terrain surface from a five-point
sampling (filled circles) of a square-grid digital elevation model (DEM)
(subset of 24 heights shown as circles). Calculation for center point O (see
fig. 2) averages E-W and N-S slope values defined by neighboring heights X1
and X2 and Y1 and Y2, respectively. Point O is relocated at each height
value in the DEM, and the calculation is repeated. Results are used to
compute slope normal and angle i (fig. 2) for text equation 1. M ap in
figure 4 was created by these calculations. 

Figure 4.  Digital shaded-relief map of the conterminous United States.
Image processed from 6,096x3,800-pixel array containing some 12 million
terrain heights. Sun elevation is 25 degrees; Sun azimuth, 300 degrees;
vertical exaggeration, 2X. Topographic features as small as 1.6 km across on
the ground can be distinguished on the full-size map published at
1:3,500,000 scale (Thelin and Pike, 1991). Image is about 4,000 km across
(prepared by Gail Thelin). 

Figure 5.  Portion of 1:1,200,000-scale map of Italy (Reichenbach and
others, 1992) showing Sicily and southwest Calabria in shaded relief.
Computed from new Italian digital elevation model of about 8 million
elevations (500,000 in Sicily). Sun is 30 degr ees above the western
horizon; no vertical exaggeration. Image shows details of Sicilian
Apennines, Mt. Etna, and the limestone Ragusa Plateau in the southeastern
part of the island. Image is about 325 km across (prepared by Paola
Reichenbach and William Acevedo). 

Figure 6.  Shaded-relief map of the entire Mediterranean sea floor and parts
of the Black Sea and Bay of Biscay, computed from a martix of 3 million
depths (1-km spacing) by the same image-processing techniques applied to
subariel data (Mark and others, 1 991). Sun elevation is 30 degrees; Sun
azimuth, 315 degrees; vertical exaggeration, 7X. Image is about 2,000 km
across (prepared by Robet Mark from data supplied by the Consiglio Nazionale
delle Ricerche, Bologna, Italy). 

Figure 7.  Shaded-relief image of Italy and surrounding floor of the
Mediterranean Sea, combined from separate digital models used to compute
figures 5 and 6. Triangular area is the Tyrrhenian microplate, a tectonic
unit of the crust that is prone to much seismic and volcanic activity; no
coastline is indicated. Areas (including Corsica) not covered by data shown
in uniform dark-gray tone. Shading parameters are same as in figure 6. Image
is about 1,000 km across (prepared by Robert Mark). 

Figure 8.  Shaded-relief map of the 1:100,000-scale San Jose quadrangle,
California. Area located at southern end of San Francisco Bay includes most
of Santa Clara County. Main topographic features, from west to east, are
Santa Cruz Mountains (site of 1989 Loma Prieta earthquake), Santa Clara
Valley, Diablo Range, and Central Valley. One of 20 maps of elevation
derivatives made from a new matrix of points spaced at 2 arc-seconds (about
50 m ) (Pike and others, 1992). Sun elevation is 25 degrees; Sun azimuth,
270 degrees; vertical exaggeration, 4X. Image is about 90 km across
(prepared by William Acevedo). 

Figure 9. Hilly, landslide-prone terrain astride the San Andreas fault zone
in northern San Mateo County, Calif. Same area is shown in digital
shaded-relief under constant Sun elevation (30 degrees) and at eight values
of Sun azimuth (in descending rows, from left to right: 0 degrees and 45
degrees, 90 degrees and 135 degrees, 180 degrees and 225 degrees, 270
degrees and 315 degrees. Data set is part of a USGS 30-m resolution digital
elevation model of the entire county (Mark and Aitken, 1990). Panels are
 15 km across (prepared by William Acevedo).

CHAPTER C 
Figure 1. Physiographic provinces in U.S. Environmental Protection
Agency Region IV and location of hazardous waste sites for test evaluation. 

Figure 2. Lithology estimated from U.S. Geological Survey 1:2,500,000-scale
geologic map of the United States. 

Figure 3. Lithology estimated from the 1:14,000,000-scale generalized
surficial-deposits map of North America. 

Figure 4. Hydraulic conductivity estimated from U.S. Geological Survey
1:2,500,000-scale geologic map of the United States. 

Figure 5. Sorptive capacity estimated from U.S. Geological Survey
1:2,500,000-scale geologic map of the United States. 

Figure 6. Hydraulic conductivity estimated from generalized
surficial-deposits map of North America. 

Figure 7. Sorptive capacity estimated from generalized surficial-deposits
map of North America. 

Figure 8. Composite hydraulic conductivity coverage.

Figure 9. Composite sorptive capacity coverage.

Figure 10. Locations of wells listed in the National Water Information
System (NWIS) that have depth-to-water data and hazardous waste sites with
15-mi-radius surrounding site. 

Figure 11. Mean annual precipitation (1931-60).

Figure 12. Mean annual lake evaporation (1946-55).

Figure 13. Annual net precipitation.

Figure 14. Difference, in percent, between field investigation team (FIT)
data and geographic information system (GIS)-derived data for evaporation,
precipitation, and net precipitation. Positive value indicates GIS value
greater than FIT value; negative value indicates GIS value less than FIT
value. 

Figure 15. Difference, in percent, between field investigation team (FIT)
data and geographic information system (GIS)-derived data for depth to
water. Positive values indicate GIS value greater than FIT value; negative
values indicate GIS value less than FIT value.

Figure 16. Difference, in order of magnitude, between field investigation
team (FIT) data and geographic information system (GIS)-derived data for
hydraulic conductivity. Positive value indicates GIS value greater than FIT
value; negative value indicates GIS value less than FIT value. 

CHAPTER D
Figure 1.  Hypothetical drainage basin.

Figure 2.  Example of a simple stream-drainage system.

Figure 3.  Example of a complex stream-drainage system.

Table 1.  Selected data for subbasins for simple stream-drainage system
shown in figure 2

Table 2.  Selected data from stream segments for simple stream-drainage
system shown in figure 2

Table 3.  Selected data for subbasins for complex stream-drainage system
shown in figure 3

Table 4.  Selected data from stream segments for complex stream-drainage
system shown in figure 3

Table 5.  Selected aggregated data for complex stream-drainage system shown
in figure 3

CHAPTER E Figure 1. Features of a digital coverage (Environmental Systems
Research Institute, Inc., 1990). 

Figure 2. A flowchart of data in a geographic information system. 

Figure 3. The benefits and drawbacks of hand digitizing versus optical scanning.

Figure 4. Comparison of a digital geologic coverage and published geologic
map for the same part of Nevada. 

Table 1. Example of format and data set for ASCII arc attribute table

Table 2. Example of format and data set for ASCII polygon attribute table

CHAPTER F Figure 1. Example of introductory text and pie charts for a
water-use category section (Solley and others, 1988). 

DOMESTIC Domestic water use includes water for normal household purposes,
such as drinking, food preparation, bathing, washing clothes and dishes,
flushing toilets, and watering lawns and gardens. In previous water-use
circulars in this series, self-supplied domes tic withdrawals were tabulated
under the Rural use category, and public-supply deliveries for domestic
purposes were included under the Public supply category as water delivered
for domestic and public uses. 

Public suppliers generally maintain reliable information about withdrawals
and population served. Information on deliveries from public suppliers to
various users was more difficult to obtain. The number of people served by
their own water systems (self s upplied) was determined by subtracting the
number of people served by public supplies from the total population as
reported by the U.S. Bureau of the Census. The difference between these
totals indicated that 42.5 million people, or 18 percent of the Nati on's
total population, were served by their own water systems in 1985 compared
with 43.5 million people in 1980, a 2-percent decrease. Self-supplied
domestic systems rarely are metered, and little firm data exist.
Self-supplied domestic withdrawals were estimated us ing per-capita-use
coefficients that ranged from 50 to 110 gallons per person per day.
Consumptive-use estimates were based on coefficients, generally ranging from
0.1 to 0.5, multiplied by withdrawals and deliveries. 

The supply (self-supplied withdrawals and public-supply deliveries) and
disposition of water for domestic purposes are shown in the chart below. The
distribution of total self-supplied domestic withdrawals and the estimates
of domestic water use (withdrawals, deliveries, consumptive use) by
water-resources region are shown in figure 3 and table 3, respectivel y.
Similar information by State is shown in figure 4 and table 4. 

The quantity of self-supplied water withdrawn for domestic purposes in 1985
was estimated to be 3,320 Mgal/d (see tables 3 and 4), or 4 percent less
than in 1980. Domestic withdrawals represent 0.8 percent of total
withdrawals for all offstream categories . Ground water was the source for
about 98 percent of self-supplied domestic withdrawals; surface water was
the source for the remaining 2 percent. Withdrawals for the population
served by their own water systems averaged about 78 gal/d for each person, a
bout the same as in 1980. 

Public suppliers delivered about 21,000 Mgal/d of water to domestic users;
this accounted for 57 percent of total public-supply deliveries.
Public-supply domestic deliveries averaged 105 gal/d for each person served.
The consumptive use of water for domestic purposes in 1985 was about 5,680
Mgal/d, or about 23 percent of self-supplied withdrawals and public-sup ply
deliveries. 

In 1985, the South Atlantic-Gulf water-resources region had the largest
self-supplied withdrawals for domestic purposes, whereas the California
region accounted for the largest total of deliveries. (See figure 3.)
Self-supplied domestic withdrawals were f airly evenly distributed among the
States. Florida and New York were the major users, accounting for 8 percent
and 6 percent, repectively. (See figure 4.)

Figure 2.  Example of cloropleth map and table for a water-use category
section (Solley and other, 1988).