Entity_Type:
Entity_Type_Label: AL_rates_ST.shp
Entity_Type_Definition:
Transects and shorelines were used to generate intersection points and shoreline change rate transects. These attributes are for short-term rates in Alabama.
Entity_Type_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: FID
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Unrepresentable_Domain:
Sequential unique whole numbers that are automatically generated.
Attribute:
Attribute_Label: Shape
Attribute_Definition: Feature geometry.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Unrepresentable_Domain: Feature type.
Attribute:
Attribute_Label: baselineid
Attribute_Definition:
Unique identification number of the baseline segment starting at 1. If baselineid= 0 no transects will be generated. Used by DSAS to determine transect ordering alongshore if multiple baseline segments exist.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 4
Attribute:
Attribute_Label: transorder
Attribute_Definition:
Number assigned by DSAS based on the ordering of transects from baseline start to baseline end.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 7
Range_Domain_Maximum: 1819
Attribute:
Attribute_Label: length
Attribute_Definition: Length of feature in meter units.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 363.76
Range_Domain_Maximum: 1593.94
Attribute_Units_of_Measure: meters
Attribute:
Attribute_Label: tcd
Attribute_Definition:
The total cumulative distance (TCD) is the measure in meters alongshore from the start of the baseline segment with an identifier of 1 and measured sequentially alongshore to the end of the final baseline segment.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 300
Range_Domain_Maximum: 90900
Attribute_Units_of_Measure: meters
Attribute:
Attribute_Label: shrcount
Attribute_Definition: Number of shorelines used to compute shoreline change metrics.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 2
Range_Domain_Maximum: 18
Attribute:
Attribute_Label: lrr
Attribute_Definition:
A linear regression rate-of-change statistic was calculated by fitting a least-squares regression line to all shoreline points for a particular transect, using shoreline position plotted against shoreline date. The best-fit regression line is placed so that the sum of the squared residuals (determined by squaring the offset distance of each data point from the regression line and adding the squared residuals together) is minimized. The linear regression rate is the slope of the line. The rate is reported in meters per year with positive values indicating accretion (shoreline advance, seaward movement) and negative values indicating erosion (shoreline retreat, landward movement). A LRR value of 9999.99 in the attribute table means that value is null. This scenario occurs when ShrCount = 2 and there are not enough data points to calculate a linear regression rate.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -62.14
Range_Domain_Maximum: 42.75
Attribute_Units_of_Measure: meters per year
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 9999.99
Enumerated_Domain_Value_Definition: null value
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: lr2
Attribute_Definition:
The R-squared statistic, or coefficient of determination, is the proportion of variance in the data that is explained by a regression. It is a dimensionless index that ranges from 1.0 to 0.0 and measures how successfully the best-fit line accounts for variation in the data. The smaller the variability of the residual values around the regression line relative to the overall variability, the better the prediction (and closer the R-squared value is to 1.0). A LR2 value of 9999.99 in the attribute table means that LR2 is null. This scenario occurs when shrcount = 2 and there are not enough data points to calculate a linear regression rate.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0
Range_Domain_Maximum: 1
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 9999.99
Enumerated_Domain_Value_Definition: null value
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: lci90
Attribute_Definition:
The standard error of the slope with confidence interval describes the uncertainty of the reported rate. The LRR rates are determined by a best-fit regression line for the shoreline data at each transect. The slope of this line is the reported rate of change (in meters/year). The confidence interval (LCI) is calculated by multiplying the standard error of the slope by the two-tailed test statistic at the user-specified 90 percent confidence. This value is often reported in conjunction with the slope to describe the confidence of the reported rate. For example: LRR = 1.2 LCI90 = 0.7 could be reported as a rate of 1.2 (+/-) 0.7 meters/year. An lci90 value of 9999.99 in the attribute table means that lci90 is null. This scenario occurs when shrcount = 2 and there are not enough data points to calculate a linear regression rate.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.12
Range_Domain_Maximum: 191.15
Attribute_Units_of_Measure: meters
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 9999.99
Enumerated_Domain_Value_Definition: null value
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: lse
Attribute_Definition:
This quantity is the standard error of the regression, also known as the standard error of the estimate. To calculate it, the distance between each data point and the regression line is calculated. These distances are squared then summed. The sum is divided by the number of data points minus two. The square root is taken of the result. A lse value of 9999.99 in the attribute table means that lse is null. This scenario occurs when shrcount = 2 and there are not enough data points to calculate a linear regression rate.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1.61
Range_Domain_Maximum: 459.33
Attribute_Units_of_Measure: meters
Attribute_Domain_Values:
Enumerated_Domain:
Enumerated_Domain_Value: 9999.99
Enumerated_Domain_Value_Definition: null value
Enumerated_Domain_Value_Definition_Source: U.S. Geological Survey
Attribute:
Attribute_Label: epr
Attribute_Definition:
The end point rate is calculated by dividing the distance of shoreline movement by the time elapsed between two shorelines, the oldest and most recent only. The rate is reported in meters per year with positive values indicating accretion (shoreline advance, seaward movement) and negative values indicating erosion (shoreline retreat, landward movement).
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -55.74
Range_Domain_Maximum: 61.77
Attribute_Units_of_Measure: meters per year
Attribute:
Attribute_Label: eprunc
Attribute_Definition:
Describes the uncertainty of the reported end point rate (EPR) in meters. The shoreline uncertainties for the two positions used in the end point calculation are each squared then added together (summation of squares). The square root of the summation of squares is divided by the number of years between the two shorelines. This result is reported as the confidence of the end point rate calculation (eprunc).
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.12
Range_Domain_Maximum: 8.20
Attribute_Units_of_Measure: meters
Attribute:
Attribute_Label: nsm
Attribute_Definition:
The net shoreline movement (NSM) is the distance in meters between the oldest and the most recent shorelines.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -447.72
Range_Domain_Maximum: 678.32
Attribute_Units_of_Measure: meters
Attribute:
Attribute_Label: sce
Attribute_Definition:
The shoreline change envelope (SCE) value represents the greatest distance that covers all the shorelines intersected by a transect. The value for SCE is always positive, as the metric is based on magnitude, not direction.
Attribute_Definition_Source: U.S. Geological Survey
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 5.53
Range_Domain_Maximum: 1078.36
Attribute_Units_of_Measure: meters
Entity_and_Attribute_Overview:
The entity and attribute information provided here describes the tabular data associated with short-term shoreline change rates for Alabama. Please review the individual attribute descriptions for detailed information. All calculations for length are in meter units, NAD_1983_2011_UTM_Zone_16N.
Entity_and_Attribute_Detail_Citation: U.S. Geological Survey