Geometric Quality in Geographic Information

2005 ◽  
pp. 266-270 ◽  
Author(s):  
José Francisco Zelasco ◽  
Gaspar Porta ◽  
José Luis Fernandez Ausinaga
Keyword(s):  
Quality Control ◽  
Geographical Information Systems ◽  
Numerical Models ◽  
Geographical Information ◽  
Actual Surface ◽  
Digital Elevation ◽  
Geometric Precision ◽  
Point Density ◽  
The Difference ◽  
Geometric Quality

A typical way to build surface numerical models or Digital Elevation Models (DEMs) for Geographical Information Systems (GIS) is by processing the stereo images obtained from, for example, aerial photography or SPOT satellite data. These GIS can perform many computations involving their geographic databases. The quality control of a geographic database, and in particular the topological and geometric integrity, are, therefore, important topics (Guptill & Morrison, 1995; Harvey, 1997; Laurini & Milleret-Raffort, 1993; Ubeda & Servigne, 1996). The geometric quality control of the stored DEM is what we are concerned with here. “Quality” means the geometric precision measured in terms of the difference between a DEM and a reference DEM (R-DEM). We assume the R-DEM is a faithful model of the actual surface. Its point density may be greater than the DEM point density.

Visualization of Urban Prediction Using Augmented Maps

2012 ◽  
Author(s):  
Sandy Martedi ◽  
Sébastien Callier ◽  
Hideo Saito ◽  
Pega Sanoamuang ◽  
Milica Muminović
Keyword(s):  
Geographical Information Systems ◽  
Green Space ◽  
Geographical Information ◽  
Train Station ◽  
Monitor Display ◽  
Before And After ◽  
Web Camera ◽  
On Line ◽  
The Difference ◽  
The Impact

In this paper, we explore a visualization method using augmented maps for urban prediction. Our implementation allows users to determine the location for prediction in a paper map. As an application example, we examine an area before and after new train station is built. We use the difference between two maps for simulating the changes or predicting the impact if a new train station is built on a location in a paper map. In off-line phase, we gather knowledge data from several reference locations by comparing two aerial maps (before and after the train station is built). We then analyze the difference of green spaces between those two maps using color extraction. We observe that the green space around the new train station mostly decreases due to the area development. This information is then stored for prediction reference. In on-line phase, we use a monocular setup that consists of one camera and a monitor display. A paper map is captured using a web camera and tracked using its geometrical features. These features can be provided using the available data from Geographical Information Systems (GIS) or automatically extracted from the texture. The map is then matched with the reference map in database. When the map is matched, we can overlay the simulation on how the green space will change due to the existence of new train stations on a new location inputted by the user.

scholarly journals Monitoring air quality, objectives and design

2008 ◽  
Vol 14 (3) ◽  
pp. 167-171 ◽  
Author(s):  
Bjarne Sivertsen
Keyword(s):  
Quality Assurance ◽  
Information Systems ◽  
Air Quality ◽  
Data Quality ◽  
Geographical Information Systems ◽  
Data Transfer ◽  
Quality Management System ◽  
Numerical Models ◽  
Monitoring Programme ◽  
Geographical Information

Today's environmental information systems combine the latest sensor and monitor technologies with data transfer; data base developments, quality assurance, statistical and numerical models and advanced computer platforms for processing, distribution and presenting data and model results. Geographical Information Systems (GIS) are an important tool, particular for the presentation of data. An important part of the integrated air quality management system is the establishment of a monitoring programme for air quality. Once the objective of the air monitoring programme is well defined, a certain operational sequence has to be followed. The best possible definition of the air pollution problem, together with the analysis of the personnel, budget and equipment available, represent the basis for the final design. The specification of monitoring objectives, data quality objectives together with proper site selection, data quality assurance and well-defined data presentation and assessment are important elements in this process.

scholarly journals Linking geomorphic systems theory and remote sensing : a conceptual approach to Alpine landform detection (Reintal, Bavarian Alps, Germany)

2006 ◽  
Vol 61 (3) ◽  
pp. 181-190 ◽  
Author(s):  
N. J. Schneevoigt ◽  
L. Schrott
Keyword(s):  
Remote Sensing ◽  
Systems Theory ◽  
Geographical Information Systems ◽  
Systems Approach ◽  
Geographical Information ◽  
High Mountain ◽  
Conceptual Approach ◽  
Bavarian Alps ◽  
Digital Elevation ◽  
Process System

Abstract. Although the global importance of high mountains is increasingly being recognised, their geomorphic process System has not been completely understood as yet. While Systems theory and geographical information Systems (GIS) approaches have been long-serving in alpine geomorphology, the implementation of remote sensing (RS) tools is still rare. However, objeet-oriented image analysis lends itself to alpine applications, as it unites the benefits of RS and GIS. The Systems approach and the object-oriented classification of an ASTER satellite scene with digital elevation information are parallelized in the Reintal (Bavarian Alps). In a hierarchical, multiscale data segmentation and Classification, alpine landforms can be detected with high accuracy. Hence, RS techniques represent a valuable tool for high mountain geomorphology.

scholarly journals A strategy to address the task of seismic micro-zoning in landslide-prone areas

2013 ◽  
Vol 35 ◽  
pp. 23-35 ◽  
Author(s):  
G. Vessia ◽  
M. Parise ◽  
G. Tromba
Keyword(s):  
Peak Ground Acceleration ◽  
Geographical Information Systems ◽  
Clayey Soil ◽  
High Energy ◽  
Geographical Information ◽  
Ground Acceleration ◽  
Digital Elevation ◽  
Sliding Mechanism ◽  
Italian Apennines

Abstract. As concerns landslide prevention and mitigation policies at the urban scale, the ability of Geographical Information Systems (GIS) to combine multi-layered information with high precision enables technicians and researchers to devote efforts in managing multiple hazards, such as seismically induced instability in urbanized areas. As a matter of fact, many villages in the Italian Apennines, placed near high-energy seismic sources, are characterized by active sliding that are seasonally remobilized by rainfall. GIS tools can be useful whether accurate Digital Elevation Models (DEM) are available and detailed mechanical and hydraulic characterization of superficial deposits over significant portion of the urban territory is undertaken. Moreover, the classic methods for estimating the seismic-induced permanent displacements within natural slopes are drawn from the generalization of Newmark's method. Such method can be applied to planar sliding mechanism that can be considered still valid wherever shallow landslides are generated by an earthquake. The failure mechanism depends on the mechanical properties of the superficial deposits. In this paper, the town of Castelfranci (Campania, southern Italy) has been studied. This small town, hosting two thousand inhabitants, suffers from the seasonal reactivation of landslides in clayey soil deposits due to rainfall. Furthermore, the site is seismically classified by means of the peak ground acceleration (PGA) equal to 0.246 g with respect to a 475 yr return period. Several studies on the evolution of slopes have been undertaken at Castelfranci and maps have been drawn at the urban scale not taking into any account the seismic hazard. This paper shows possible seismically induced hazard scenarios within the Castelfranci municipal territory aimed at microzonation of level 2, by estimating the slope permanent displacements comparable to those caused by the strongest historical seismic event that hit this area: the 1980 Irpinia earthquake. To this aim, geotechnical characterization of local soils collected over the last 25 yr by local technicians have been used to predict possible permanent displacements by means of Newmark's sliding block approach. Two simplified relationships relating peak ground acceleration and Arias intensity to permanent displacements have been used and compared. Although similar results are drawn, the two analyses point out the most hazardous sectors of the Castelfranci urban area.

scholarly journals Quality Control and Management of Inspection and Data Collection

2000 ◽  
Author(s):  
Robert A. Simmons ◽  
Richard Kania
Keyword(s):  
Quality Control ◽  
Data Collection ◽  
Geographical Information Systems ◽  
Geographical Information ◽  
Quality Data ◽  
Inspection Time ◽  
Accurate Information ◽  
Pipeline System ◽  
Complex Data ◽  
Practical Applications

Geographical Information Systems, Data trending, and Risk Assessment Software are now available to help pipeline operators execute safe, cost effective maintenance programs. However, to use these analytical tools effectively, large amounts of data pertaining to the integrity of the pipeline system and its environment are required. For this reason, pipeline rehabilitation programs have evolved into complex data collecting procedures, the success of which depends on the ability to efficiently obtain reliable, consistent and accurate information. This article will describe new software technology and Quality Control programs, relating to inspection personnel, which have been developed to increase the efficiency and reliability of the information collected during a pipeline excavation. The pertinent functions of software programs discussed will involve compatibility between databases, on site data validation, code calculations, communications and CAD drawings for a comparison with In Line Inspection results. As well, the need for quality control or training programs will be discussed addressing both the theoretical and practical applications of pipeline integrity and it’s relevance to quality data collection. Previous projects using these approaches will be presented showing their effectiveness in significantly increasing the efficiency and accuracy of the information collected while reducing overall inspection time and cost.

Assessment of flora diversity in a minor river valley using ecological indicator values, Geographical Information Systems and Digital Elevation Models

2014 ◽  
Vol 9 (2) ◽  
pp. 220-231 ◽  
Author(s):  
Bożenna Czarnecka ◽  
Łukasz Chabudziński
Keyword(s):  
Information Systems ◽  
Geographical Information Systems ◽  
Digital Elevation Models ◽  
River Valley ◽  
Geographical Information ◽  
Ecological Indicator ◽  
Indicator Values ◽  
Vascular Flora ◽  
Digital Elevation ◽  
A Minor

AbstractEllenberg indicator values (EIV) have been widely used to estimate habitat variables from floristic data and to predict vegetation composition based on habitat properties. Geographical Information Systems (GIS) and Digital Elevation Models (DEM) are valuable tools for studying the relationships between topographic and ecological characters of river systems. A 3-meter resolution DEM was derived for a. 3-km-long break section of the Szum River (SE Poland) from a 1:10,000 topographic map. Data on the diversity and ecological requirements of the local vascular flora were obtained while making floristic charts for 32 sections of the river valley (each 200 m long) and physical and chemical soil measurements; next, the data were translated into EIV. The correlations of the primary and secondary topographic attributes of the valley, species richness, and EIV (adapted for the Polish vascular flora) were assessed for all species recognized in each valley section. The total area and proportion of a flat area, mean slope, slope curvature, solar radiation (SRAD), and topographic wetness index (TWI) are the most important factors influencing local flora richness and diversity. The highest correlations were found for three ecological indicators, namely light, soil moisture, and soil organic content. The DEM seems to be useful in determination of correlations between topographic and ecological attributes along a minor river valley.

scholarly journals Obtenção Automática da Rede de Drenagem a Partir de Modelos Digitais de Altitude

1998 ◽  
Vol 25 (1) ◽  
pp. 89
Author(s):  
LUCIENE DELAZARI SKROCH ◽  
QUINTINO DALMOLIN ◽  
ANTONIO JOSÉ BERUTTI VIEIRA
Keyword(s):  
Information Systems ◽  
Data Base ◽  
Geographical Information Systems ◽  
Digital Elevation Models ◽  
Geographical Information ◽  
Drainage Network ◽  
Alternative Option ◽  
Drainage Networks ◽  
Digital Elevation

The extraction of drainage network based on manual techniques is a tedious and time consuming task. Some methods are available in the literature to automatically extract drainage networks from Digital Elevation Models (DEM), but the main software developed in Brazil aiming at generation of cartographic data base and Geographical Information Systems (GIS), do not deal with this kind of approach. The SKEL program, a software developed at the Israel University in order to provide drainage network based on DEM, is an alternative option which deserves to be evaluated. Thus, a DEM from an area of about 35km2 was selected for the evaluation. The results of investigation have shown that the approach can be used for the extraction of drainage networks, but some drawbacks were detected, mainly related to the intermediate steps of files conversion and the DEM generation.

scholarly journals Determination of Imperviousness in the Highland Creek Watershed

SURG Journal ◽  
2009 ◽  
Vol 3 (1) ◽  
pp. 26-30
Author(s):  
Angelin Satgunarajah
Keyword(s):  
Land Use ◽  
Geographical Information Systems ◽  
Geographical Information ◽  
Aerial Photographs ◽  
Watershed Area ◽  
A Value ◽  
Impervious Area ◽  
Creek Watershed ◽  
Severe Impairment ◽  
The Difference

The Highland Creek watershed, an area of about 100 square kilometres in the region of Toronto, was selected for this study. As a highly urbanized area, construction of roads and buildings has increased the region’s imperviousness to watershed, which can cause severe impairment to both the quality and quantity of water. The imperviousness of this region therefore needed to be assessed to manage the watershed area effectively, and to improve future development projects. The task of assessing the watershed area was accomplished using digitized aerial photographs and Geographical Information Systems (GIS). Because GIS does not give detail total road area of land use, the difference between total area and impervious area was calculated and assigned as a total road area. The ratio between the impervious area and the total area was calculated to assess the impervious ratio of the watershed area, and was assigned a value of 0.533. Using this method, more than 120 subcategories can be selected within this watershed area, and the imperviousness can be calculated using land use subcategory ratios and averages ratios.

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