Causes and consequences of error in digital elevation models
Bibliography ; Digital elevation model ; Error ; Methodology ; Model ; Physical geography ; Typology
This paper reviews research on the understanding, modelling and propagation of error in DEMs, with the aim of presenting a comprehensive statement of the issues surrounding these topics : sources of error in DEMs, error models, error propagation
, visualization of error, error correction and fitness for use.
Error propagation in quantitative spatial modelling. Applications in Geographical Information Systems
Error ; Geographical information system ; Modelling ; Spatial statistics ; Statistics
This book deals with the different aspects of the problem of error and error propagation in GIS. It is restricted however to the propagation of quantitative attribute errors in logical, empirical and conceptual models that are used in, or with GIS
. This means that neither positional error nor the propagation of qualitative or categorical errors are dealt with. - (AGD)
Evaluation of model performance when the observed data are subject to error
This paper addresses the effect of observational errors on the mean squared error, the mean bias error and the mean absolute deviation through the derivation of a statistical framework and Monte Carlo simulation. Examination of scaled differences
between modelled and observed values, where the differences are divided by the estimated standard errors of the observed values, is suggested as a diagnostic tool for determining whether random observational errors are significant.
The model accounts for errors in short-cutting to complete a triangular pathway by individuals deprived of visual input. It assumes that systematic error arises from components of navigation concerned with encoding an internal representation
This work analyzes Minimum Curvature distributions to identify the statistical signature of 2 types of LiDAR-DTM errors (outliers and striping artifacts) in the derived estimates, rather than morphology itself. The analysis shows the importance
of modeling these errors correctly, in relation to the scale of analysis and DTM resolution, in order to have reliable curvature estimates. Nine DTMs of different morphological areas are considered, and grouped into a training dataset (without errors
) and a test dataset (with errors). This study shows that the curvature distributions are impacted upon differently by striping artifacts and outliers, and that these are clearly distinguishable from the signal of morphological features : a scale-dependent
change in curvature distribution can therefore be interpreted as the signature of these specific errors, rather than morphology.
Point-counting technique for fission-track dating of tephra glass shards, and its relative standard error
Dating ; Error ; Geochronology ; Methodology ; New Zealand ; North Island ; Quaternary ; Statistics ; Tephrochronology
In this work, the AA. consider a procedure called point counting that significantly reduces the counting times, but also introduces an additional source of error. They study this additional error and provide a simple formula for estimating
the relative standard error of a fission-track density determined by the point-counting technique. In conclusion, this study has shown that, especially for very low track densities which are typical of Quaternary tephra, the point-counting technique can
Measuring neighbourhood spatial accessibility to urban amenities : does aggregation error matter ?
Accessibility ; Aggregation ; Error ; Residential environment ; Statistics ; Urban area ; Urban district ; Urban infrastructure
Aggregation error arises when a single point is used to represent a neighbourhood. The spatial accessibility to three types of recreational amenities in Edmonton, is used to assess whether aggregation error affects the measures. Exploratory spatial
data analysis techniques are used to examine aggregation-error effects on spatial accessibility.
Detailed methods are presented for the estimation of errors in quantifying channel migration rates that can be easily applied to GIS-based analysis of planform change. In addition, the impact of relaxing assumptions regarding error independence
between image dates and systematic registration errors is presented and discussed.
Precipitation data are important for hydrology, climatology, geography etc. Discussed are systematic errors that occur at the standard method of precipitation measurements using rain gauges. The components of the systematic error are related
This paper describes an alternative ex situ core permeametry technique that is field based. The potential sources of precision and bias error within the method are quantified and their effect on the uncertainty of permeability estimates
The AA. propose a statistical model for incorporating location error into spatial data analysis. They investigate the effect of location error on the spatial lag, the covariance function, and optimal spatial linear prediction.
Data base ; Error ; Geographical information system ; Numerical model ; Photogrammetry ; Simulation ; Slope ; Slope gradient ; Spatial analysis ; Statistics
The AA. show that errors in slope and aspect depend on the spatial structure of digital elevation models (DEM) errors. They propose a general-purpose model of DEM errors in which a spatially autoregressive random field is added as a disturbance term
to elevations. In addition, they propose a general procedure for propagating such errors through GIS operations. In the absence of explicit information on the spatial structure of DEM errors, they demonstrate the potential utility of a worst-case analysis
. A series of simulations are used to make general observations about the nature and severity of slope and aspect errors.
Using sediment fingerprints to assess sediment-budget errors, North Halawa Valley, Oahu, Hawai, 1991-92
Aeolian features ; Aerosol ; Error ; Hawaii ; Methodology ; Sediment budget ; Suspended load ; Tropical zone ; Watershed
Reliable estimates of sediment-budget errors are important for interpreting sediment-budget results. The AA. modified the sediment fingerprinting approach to qualitatively evaluate compensating errors in an annual (1991) fine sediment budget
imbalances provide a measure of compensating errors in the sediment budget.
Predicting ordinary kriging errors caused by surface roughness and dissectivity
The aim of this paper is to determine the association of ordinary kriging (OK) estimated errors with the local variability of surface roughness, and to analyse the suitability of probabilistic models for predicting the magnitude of OK errors from
surface parameters. The results underscore the importance of the role of the local diversity of relief properties in increasing or decreasing the magnitude of interpolation errors. The newly developed dissectivity parameters provide useful information
for terrain analysis. The study also provides constructive guides to understanding the local variation of interpolation errors and their dependence on surface dissectivity.