Design and Statistics, Indicator Development, Information Management, Assessment and Reporting, Logistics, Methods, and Quality
Assurance.
Cumulative distribution
A means of representing the variation of some attribute by giving
running totals of the resource with attribute values less than or equal
to a specified series of values. For example, a cumulative areal
distribution of lakes would give, for any value of area, the total
area covered by lakes with individual area less than or equal to
alpha. A cumulative frequency distribution for lake area would give
the total number of lakes with area less than or equal to alpha. The
cumulative distribution function (cdf) of some specified attribute of
a population is the function F(x) that gives the proportion of the
population with value of the attribute less than or equal to x, for any
choice of x. For example, if the attribute was lake area in hectares, F
(a) would give the proportion of lakes with area less than or equal to
a ha. (In some cases, the word “cumulative” may be omitted in
discussions of the cdf, and the cdf is called the distribution
function.)
Cylindrical (or cylindric)
map projection
One of a class of map projections formed by projecting coordinates
from the earth’s surface onto a cylinder that either intersects the
surface in two small circles or is tangent to a great circle on the
surface. When the cylinder intersects the surface, the projection is
said to be the secant case.
Data quality
The totality of features and characteristics of data that bears on their
ability to satisfy a given purpose; the sum of the degrees of excellence for factors related to data.
Data quality indicators
“Quantitative statistics and qualitative descriptors that are used to
interpret the degree of acceptability or utility of data to the user. The
principal data quality indicators are bias, precision, accuracy, comparability, completeness, and representativeness.”
Data quality objective
(DQO)
“Quantitative and qualitative statements of the overall level of
uncertainty that a decision-maker is willing to accept in results or
decisions derived from environmental data DQOs provide the statistical framework for planning and managing environmental data
operations consistent with the data user’s needs.” A data quality
objective may include goals for accuracy, precision, and limits of
detection. It may also include goals for completeness, comparability, and representativeness. Data quality objectives are established
before sampling is begun and may influence the level of effort
required to select a sample.
Deconvolution
The process of removing the influence of extraneous variation from
an apparent cumulative distribution. Extraneous variation – such as
random errors in measurement – has the effect of inflating observed
variation relative to true population variation. The cumulative distribution that will be estimated when extraneous variation is present
is the convolution of the population distribution (which is the
cumulative distribution of interest) and the distribution of the extraneous variable. The convolution cumulative distribution will be
flatter (have longer tails) than the population cumulative
distribution.
Demonstration field
program
A collection of demonstration research projects to provide preliminary estimates of resource condition for one or more indicators
applied to one or more resource classes over a standard federal
5 Geographic Information Systems and Remote Sensing Applications in Environmental. . . 221
Assurance.
Cumulative distribution
A means of representing the variation of some attribute by giving
running totals of the resource with attribute values less than or equal
to a specified series of values. For example, a cumulative areal
distribution of lakes would give, for any value of area, the total
area covered by lakes with individual area less than or equal to
alpha. A cumulative frequency distribution for lake area would give
the total number of lakes with area less than or equal to alpha. The
cumulative distribution function (cdf) of some specified attribute of
a population is the function F(x) that gives the proportion of the
population with value of the attribute less than or equal to x, for any
choice of x. For example, if the attribute was lake area in hectares, F
(a) would give the proportion of lakes with area less than or equal to
a ha. (In some cases, the word “cumulative” may be omitted in
discussions of the cdf, and the cdf is called the distribution
function.)
Cylindrical (or cylindric)
map projection
One of a class of map projections formed by projecting coordinates
from the earth’s surface onto a cylinder that either intersects the
surface in two small circles or is tangent to a great circle on the
surface. When the cylinder intersects the surface, the projection is
said to be the secant case.
Data quality
The totality of features and characteristics of data that bears on their
ability to satisfy a given purpose; the sum of the degrees of excellence for factors related to data.
Data quality indicators
“Quantitative statistics and qualitative descriptors that are used to
interpret the degree of acceptability or utility of data to the user. The
principal data quality indicators are bias, precision, accuracy, comparability, completeness, and representativeness.”
Data quality objective
(DQO)
“Quantitative and qualitative statements of the overall level of
uncertainty that a decision-maker is willing to accept in results or
decisions derived from environmental data DQOs provide the statistical framework for planning and managing environmental data
operations consistent with the data user’s needs.” A data quality
objective may include goals for accuracy, precision, and limits of
detection. It may also include goals for completeness, comparability, and representativeness. Data quality objectives are established
before sampling is begun and may influence the level of effort
required to select a sample.
Deconvolution
The process of removing the influence of extraneous variation from
an apparent cumulative distribution. Extraneous variation – such as
random errors in measurement – has the effect of inflating observed
variation relative to true population variation. The cumulative distribution that will be estimated when extraneous variation is present
is the convolution of the population distribution (which is the
cumulative distribution of interest) and the distribution of the extraneous variable. The convolution cumulative distribution will be
flatter (have longer tails) than the population cumulative
distribution.
Demonstration field
program
A collection of demonstration research projects to provide preliminary estimates of resource condition for one or more indicators
applied to one or more resource classes over a standard federal
5 Geographic Information Systems and Remote Sensing Applications in Environmental. . . 221