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GW 3 - 3th and 4th Italian GRASS users meeting proceedings


copertina GW 3

Authors Title
Blazek R., Neteler M.
Abstract
Demonstration of the new GRASS 5.1 vector features
Calabrese M., D'Aurizio C., Spoltore D.
Abstract
Models and tools for the ecological networks: landscape ecology and GIS
R. Ciampalini, S. Carnicelli
Abstract
Comparison of morphometric algorithms in GRASS
Full Text
Ciolli M., Bezzi M, Cantiani M.G., Cherubini P., Comunello G.
Abstract
Integration of dendrochronology and GIS techniques to study avalanche phenomena
Full Text
Ciolli M., Rea R., Vitti A., Zardi D., Zatelli P.
Abstract
An integrated use of 2D and 3D raster modules for atmospheric fluxes modeling in GRASS
Full Text
Ciolli M., Zatelli P.
Abstract
GRASS applications: an overview
Full Text
D'Incà D., Zatelli P.
Abstract
New modules for satellite surveying planning in GRASS
Full Text
Furlanello C., Merler S., Menegon S., Paoli E., Fontanari S.
Abstract
Mapping the Risk of Unexploded Bombs from World War Two
Guastella F., Sboarina C.
Abstract
Analysis of food habit of chamois using GIS
Full Text
Marchesini I., Fredduzzi A.
Abstract
Preliminary results of a study of the morphologic - planimetric variation of a central Italy creek
Full Text
Napolitano R., Skert N., Turco S.
Abstract
Waste dumps: mapping of the potential risk by integration of biomonitoring and GIS methodologies
Pirotti F., Vettore A.
Abstract
Contrast Filter in Pre-Processing Digital Images Used for Classification
Full Text
Agugiaro G., Salemi G.
Abstract
Integrazione di metodologie VAS e VIA con Grass. Case study: la tangenziale ovest di Padova
Turco S., Napolitano R., Altobelli A., Feoli E., Bonfanti P.
Abstract
The NDVI as indicator of the abandonment status in mountain regions. Case study: the Comunit�Montana of the Natisone Valleys-FVG
Vitti A.
Abstract
3d phenomena modeling in GRASS: implementation and applications
Full Text
Zampa F., Ciolli M., Cantiani M.G.
Abstract
A GIS procedure to map forests with a particular protective function
Full Text
Zanoni M., Cemin A., Ciolli M., Nave D.
Abstract
Integrated management of traffic data and modeling of road traffic pollutant for the town of Trento
Zatelli P.
Abstract
Multiresolution analysis with GRASS
Full Text


The Abstract

Demonstration of the new GRASS 5.1 vector features
Radim Blazek, Markus Neteler
The presentation focuses on the new GRASS 5.1 vector library features which intends to overcome the limited vector capabilities of GRASS 4.x-5.0. The the new vector library (handling geometry), the database management interface (attributes management) and new or updated vector commands are shown in a demonstration.
GRASS 5.1 allows the user to store 2D and 3D vector geometry data in native format or into a connected PostGIS system. Data from GRASS 4.x-5.0 can be converted, SHAPE files and PostGRASS (requires PostGIS) data are directly supported without importing them.
Basic TIN support is implemented. Point data (former sites files) storage has been migrated to vector format. A spatial index increases significantly the speed of accessing and processing large vector data sets. Basic functionality for vector networking is available.
Attributes management in databases is integral part of the GRASS 5.1 vector architecture and implemented as a common interface with drivers for various RDBMS. Attributes may be stored in dBase files or tables in PostgreSQL, mySQL or other RDBMS connected through ODBC. One map may contain multiple layers which are linked to different attribute tables. The common management interface is simplifying the table handling. All queries are SQL based, a new forms library provides user friendly dialog windows to directly update attributes in a map.
A graphical user interface for each module is generated on run time. Command line support is available as well. A new display manager and new digitizing tool are integrated. Vector export is based on OGR library to write formats vector such as SHAPE file, TIGER, MapInfo and GML files.
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Models and tools for the ecological networks: landscape ecology and GIS
Maurizio Calabrese, Claudia D'Aurizio, Daniela Spoltore
download abstract: a_mccdads.pdf
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Comparison of morphometric algorithms in GRASS
R. Ciampalini, S. Carnicelli
In geomorphology, and in its application to pedology, quantitative morphometry is a useful analysis tool. The wide diversity of published algorithms affords such a range of choices that some general criteria is necessary.
Specifically, algorithms for calculating land surface curvature(s) have been published by several authors (Evans, 1972, Horn, 1981, Zevenbergen & Thorne, 1987, Mitasova e Hofierka, 1993, Shary et al., 2001). A comparison is of special interest for two reasons:
1) the various solutions sometimes address physically different quantitities
2) results, specially for along-slope curvature, are often unatisfactory due to excess fragmentation
This study analyzes the different analytical solutions adopted, and the physical significance of the calculated parameters with respect to soil conservation applications.
Analytical solutions used in the GRASS module s.surf.rst are generally the most significant on this account, but:
1) it may be required, for different purposes, to calculate other parameters
2) it is often necessary to calculate such parameters from third party DEMs
3) such DEMs are of variable quality
It is then useful to have available numerical solutions applicable to raster DEMs, using the r.mapcalc module and bash scripts, and of a base to choice different solutions accordinf to data quality.
We present then a fast procedure to assess the quality of third party DEMs, and then analyse the performance of the numerical solutions proposed by Evans (1972), Horn (1981, used in the r.slope.aspect module) and Zevenbergen & Thorne (1987).
These solution yield partial derivatives usable to calcualte all of the indexes proposed by Shary et al. (2001), but have differences which suits them more or less to different DEM qualities and purposes of the analysis. The results produced by the different algorithms are compared, with the help of a procedure to evaluate the fragmentation of the results.
Analysis of the results obtained yields useful indications for the selection of the appropriate algorithm, according to purpose and data quality.
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Integration of dendrochronology and GIS techniques to study avalanche phenomena
Ciolli M., Bezzi M., Cantiani M.G., Cherubini P., Comunello G.
Snow avalanches are one of main natural hazard for human activities and infrastructures in the Alpine regions. In the last years the opening up of the mountain for tourism has increased the risk potential of this natural hazard. Information about the frequency and the extensions of these phenomena is a prerequisite for environmental management in the mountain regions. By integrating dendrochronological and GIS techniques it is possible to reconstruct the frequency and the extensions of these past events. The aim of this work is to reconstruct the past avalanche events which occurred in two avalanche paths in the Pejo Valley (Northern Italy). Dendrochronology has been used to date the past snow avalanches for the last 100 years; GRASS-GIS has been used to obtain an avalanche risk map based on morphological and vegetation features and to create maps of different avalanche paths through the years. All the results were compared with historical data available from written records, for the period 1970-2000, chosen like period of calibration. The good correlation shows the efficacy of this methodology for avalanches forecast and for the creation of new possible location avalanche map (CLPV).
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An integrated use of 2D and 3D raster modules for atmospheric fluxes modeling in GRASS
Ciolli M., Rea R., Vitti A., Zardi D., Zatelli P.
Numerical simulation of atmospheric phenomena closely depending on interaction with ground requires a detailed representation of values of various fields of distributed land variables such as solar irradiance, local slope and exposition, land covering, underground nature and so on. In some cases it is convenient to integrate simple models simulating the phenomena above into a system for management of geographic information. However, the intrinsic 3D nature of these phenomena has been so far an obstacle to the implementation of suitable models, due to the impossibility of managing such data by means of the available Geographic Information Systems. The modules which have been recently made available in GRASS for management and treatment of 3D data allow the development of suitable algorithms by combination of both 2D and 3D data and modules. In the present work we show some preliminary results of a simulation of slope winds which develop along sloping valley side-walls due to ground heating or cooling. Simple classical parameterizations of wind and temperature profiles, obtained in the case of plain tilted slope (Prandtl, 1942; Defant, 1949), have been used along with distributed data over a 2D domain (incidence radiation, land nature and use, local slope from DTM, etc.) to evaluate a suitable energy balance at ground level and fields of meteorological variables such as air temperature, pressure and wind velocity in a 3D domain over a surface. In particular two different methods have been developed to evaluate the normal vector to the surface and the distance of a given point from the surface, which are key parameters for the subsequent application of atmospheric models. The first method for the evaluation of the line connecting a point P within the valley to the underlying boundary surface consists in identifying that point over the surface which displays minimum distance from P. Within a volume divided in discrete cells it is possible to take into account slope inclination and orientation at cell ground which satisfies the minimum distance condition from the cell centered in P. The second method for the identification of the normal to the surface consists in dividing the volume above the surface in layers, and then using the 3D algebra (r3.mapcalc) to evaluate the normal, according to the surface shape. Further developments will include an optimization of parameterization adopted in the model and tests check by compare with both the output of other models and field measurements.
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GRASS applications: an overview
Ciolli M., Zatelli P.
In the last few years, GRASS GIS has known wide popularity as it is well documented by the recent GRASS Users conferences, both at national and international levels. It is therefore possible to give an organized overview of a wide amount of applications of this GIS to many different topics and problems. The range of applications goes from environmental modeling to DTM validation, from atmosphere modeling to LIDAR data elaboration, from wildlife management to Avalanche risk assessment, from GPS planning to geomorphologic modeling. Because of the Open source and free software development model of GRASS, the development and the applications are entwined, giving each other new momentum. Moreover, because of the current intense development of GRASS it is possible to foresee exciting and entirely new fields of applicability especially for 3D modeling, time series elaboration and Data Base management.
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New modules for satellite surveying planning in GRASS
D'Incà D., Zatelli P.
Satellite surveying techniques are gaining always more relevance for several application fields such as surveying, environmental monitoring and navigation. The main benefit of these techniques is the possibility of establishing the position of points even when they are not visible to each other, but at least four satellites must be visible at the same time. In practical surveying natural (mountains, etc.) or manmade (buildings, etc.) obstacles often hide satellites signal to the receiver.
It is therefore important to know in advance where signal will be concealed by obstacles and when the signals from a sufficient number of satellites will be available for the survey. Three new modules for the open source GRASS GIS has been created which automatically determine obstacles to the satellites signal to detect the satellites coverage and the PDOP value, on a time window, for a given area, using as input the digital terrain model (DTM) and the satellites almanac.
The new module r.obstruction reads the DTM and creates an ASCII file containing a polar representation of the obstructions with one degree resolution.
The new module r.planning.static uses the DTM and the obstructions file to generate four different raster maps: two raster maps representing the number of visible satellites at starting time and the minimum number of visible satellites over the chosen time span and two raster maps showing the PDOP values at starting time and the maximum PDOP values over the chosen time span. The r.planning.static module can also be used for single point planning using a map as reference for choosing the points on the graphical display with the mouse.
The third module r.planning.cinematic can be used for the planning along a trajectory. Such trajectories, in vector format, can be over the terrain surface, at constant height or fully three dimensional. Starting time and mean speed are used to estimate the time for each node. The output is given as GRASS site data, each point having four attributes: height, number of visible satellites, PDOP and time from previous point.
Satellites' positions are evaluate from the almanac as downloaded directly from the receiver or as obtained through the Internet from IGS.
Several applications of the new modules have been carried out, among these the realistic planning of geodetic surveys and the feasibility study of the satellite monitoring of wild life, in particular for the possibility of tracking the wild bears in the Alps.
The availability of the new modules in GRASS carries two main advantages: an environment to manage the geo-referenced data constituting the input and the output of the procedure and the possibility of integrating these techniques within the wide range of GIS procedures.
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Titolo_articolo
Furlanello C., Merler S., Menegon S., Paoli E., Fontanari S.
download abstract: a_cfsmsmepsf.pdf
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Analysis of food habit of chamois using GIS
Guastella F., Sboarina C.
The study aims to define the impact produced by this wild ungulate on the vegetation and the attractiveness of some vegetal species. The investigated area, 110 ha at an height between 1695 m and 2150 m a.s.l., is located within the Natural Park "Paneveggio - Pale di San Martino". On the basis of the results of the data elaboration concerning the alimentary habits of the chamois, 6 vegetation species have been chosen because of their being appetizing for the ungulate during the whole year (Rhododendrum ferrugineum, Calamagrostis villosa and Vaccinium myrtillus) or during some periods (Nardus stricta in autumn) or because generally not used (Deschampsia caespitosa and Festuca varia). The abundance percentage of these species has been calculated with geostatical methods (regularized spline with tension), using GIS GRASS, beginning from the data of the survey (88 points localised with GPS). The maps of the single species obtained with such a method have been compared using the preference index of Jacobs (1974), with the locations (about 5000) of the ungulate indicated as a total and also divided for season, in order to understand if chamois look for or avoid the different species. These locations were carried out from December 1998 till November 1999 in a parallel study with radiocollars on nineteen females (ages 1-13 years) tagged with plastic ear-tags. Radio and visual locations were made throughout the year, 5-6 times a week for each animal. For each species, according to the distribution of abundance, categories with different range have been identified, so that each category includes at least 4 % of the whole study area.
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Preliminary results of a study of the morphologic - planimetric variation of a central Italy creek
Marchesini I., Fredduzzi A.
We show the results of morfologic - planimetric variations of the Virginio Creek (Central Italy, Florence). The use of historic maps and aerial photographs helped to evaluate and quantify the active morphologic processes in the studied reach. For this kind of aim, GRASS GIS, used in the geocoding, digitizing and measuring pahses, is a good work instrument.
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Waste dumps: mapping of the potential risk by integration of biomonitoring and GIS methodologies
Napolitano R., Skert N., Turco S.
Solid wastes represent one of the most significant environmental problems of our society, because of the risks that they can cause to human health. In fact substances of various degrees of toxicity can be carried away from the dumping areas to the surroundings, causing their contamination. It is thus very important to monitor the exposure probability for the population of the zone and, therefore, the risk of serious, and sometimes irreversible, damages.
The aim of this study is to produce risk maps that integrate toxicity's maps, obtained by methods of biomonitoring (bioaccumulation of trace metals by lichens), with territorial data.
In 1997, a biomonitoring study in contaminated areas by accidental or fraudulent releases of dangerous substances was carried out. This work focused on the concentrations of 16 metals measured in Xanthoria parietina, a lichen collected in 155 stations located in the lowlands of Friuli-Venezia Giulia, near authorized, illicit or abandoned waste dumps. The interpretation of metal concentrations is based on two maps, showing, for each metal, its distribution pattern and the degree of deviation from background (natural) conditions. The joint occurrences of all metals in the stations are synthesized by a map of total metal charge and by maps based on three indices: a "naturality" index, an index of environmental alteration, and an index of potential toxicity. These maps of the metals are intersected with urban, naturalistic and agricultural areas, to obtain new maps in which the potential risk for the population and the environmental impact are shown. This is achieved with the r.infer GRASS program, an inferential engine which applies expert system type rules to a set of user raster maps.
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Contrast Filter in Pre-Processing Digital Images Used for Classification
Pirotti F., Vettore A.
Pre-processing digital images, if done accurately and with knowledge, can improve significantly the results of image classification. A locally adaptive contrast filter surely improves the visualization of elements in the image, but probably can also improve the results of classification. This paper's objective is to assess the improvement of classification accuracy of images classified after being pre-processed with a locally adaptive contrast enhancement filter added with the implementation of a new module in the GIS program GRASS, thanks to this software open-source philosophy.
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Integrazione di metodologie VAS e VIA con Grass. Case study: la tangenziale ovest di Padova
Agugiaro G., Salemi G.
The goal of this work is the developing of methodologies for the integration into a Geographical Information System of some environmental evaluation methodologies (strategic environmental evaluation and environmental impact assessment). All the work was done using the GRASS modules for raster analysis.
A real project was chosen as case study, which proposes the completion of the ring road system around Padua, across the western suburbs of the city.
However, since the project underlines the necessity of a road only in terms of traffic planning, but doesn't identify precisely its lay-out, purpose of this work is to identify the best road lay-out, including in the start-up phase some environmental aspects. In order to guarantee an interdisciplinary approach to the problem, a reference to Landscape Ecology's patch-structure for landscape analysis was made.
The database, which consists of different thematic maps (geology, land use, hydraulics hazard, etc.), was built standardizing geographical geo-referenced data coming from different sources.
After the landscape analysis, the modelling process was divided into two phases: in the first one, starting from large scale analysis, a finite number of possible road lay-outs was identified, where each one optimizes some environmental factors; in the second one, such alternatives were analyzed with other (environmental) parameters and the best one was highlighted.
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The NDVI as indicator of the abandonment status in mountain regions. Case study: the Comunit�Montana of the Natisone Valleys-FVG.
Turco S., Napolitano R., Altobelli A., Feoli E., Bonfanti P.
From the 1950's the territories of Friuli's mountains, and in particular those of the PreAlps Giulie, have been seriously neglected. The demographic decrease and the abandonment of farmland and silvopastoral activities resulted in crops, pastures and grasslands' reduction, in the suspension of shrubby and arboreal vegetation controls and, consequently, in forest colonization.
In absence of pastoral activities, vegetation evolves towards a mature stage, and then loss of phytocoenoses, habitats, ecological networks and the landscape's features follows.
The aim of this study is to propose the use of the Normalized Difference Vegetation Index (NDVI), calculated from remote sensing immagery, as a synoptic descriptor of the abandonment status in mountain regions.
This index is, in fact, strongly correlated to vegetation coverage, forest biomass, and other parameters affected by human activities that impact on the territory, i.e. the decrease in population growth and the agriculture.
The application of this indicator is explained in the case study of the Comunit�Montana of the Natisone Valleys.
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3d phenomena modeling in GRASS: implementation and applications
Vitti A.,
Many environmental phenomena such as atmospheric, geologic and water-related processes interest and developed in complex 3D domains. Often, the same phenomena interact with the landscape and closely depend on the features of the ground surface which are the classical 2D information managed by GISs. GRASS 5 supplies the capability to manage and analyze truly three-dimensional data, therefore mathematical models can be implemented to describe and simulate such phenomena. A set of 3D raster modules are available and under development. Functionalities for import and export data in and from the GRASS 3D raster format together with the capability to transfer 2D information into the 3D raster space, the three-dimensional maps algebra support and visualization tools are available. This paper presents the current state, a part of the development and maintenance work and the ongoing project on the 3D raster modules and libraries; some simple examples are also provided.
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A GIS procedure to map forests with a particular protective function
Zampa F., Ciolli M., Cantiani M.G.
The aim of this work is on one side to implement a GIS methodology to create maps of forests with particular protective function and on the other side to furnish new information to define the risk type from the point of view of the forest planning and management with the greatest possible detail.
To locate the real forests with particular protective function (bpfp) that is those forests with particular protective function that directly protect human life or important objects, a classification of the objects in order of importance has been carried out. The comparison between bpfp and forests classified with protective function in the tradictional management plans has highlighted the need to reconsider the concept of forest protection.
The method has permitted to obtain a quick delimitation of bpfp, with a procedure that can be exported and adapted to other different situations. In particular, with the aid of GRASS detailed maps that distinguish bpfp depending on different criteria have been obtained and these maps can be really effective to make easier the phase of the planning of sylviculture.
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Integrated management of traffic data and modeling of road traffic pollutant for the town of Trento
Zanoni M., Cemin A., Ciolli M., Nave D.
Aim of this work is to create an integrated system able to manage georeferenced traffic data of the town of Trento with GRASS and Postgres. The Network Service of the Comune di Trento Technical Bureau can provide a huge amount of traffic data coming from the centralized monitoring center which covers the most part of the city centre. Traffic can be considered the principal responsible of air pollution in those urban reality like Trento, where industrial plants are not present. A huge Postgres Data base containing all the available data for Trento town has been implemented. Moreover, the model Copert III has been made available into Postgres and GRASS so it allows the creation of emission maps for each measured period. GRASS has been used also to obtain pollutant concentration by means of engineering modeling of these phenomena. The system can be easily modified for a real time use, if real time data will be available.
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Multiresolution analysis with GRASS
Zatelli P.
The ability of gerarchically manage data available in a Geographical Information System is becoming increasingly important, given the huge data quantity provided by the modern surveying techniques. In particular, the spatial features of an element must be framed in an intrensically multiresolution structure with an efficient management of the information at different resolutions. Four new modules have been created for the multiresolution analysis with GRASS. These modules use the discrete wavelet transform to perform a MultiResolution Analysis (MRA) by the Mallat algorithm, which has been extended for the discrete bidimensional case. Same applications exploiting the potentiality of the technique have been carried out, among these the filtering of LIDAR data and the automatich shape recognition.
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Geomatics Workbooks n 3

Editorial Board: Maria A. Brovelli, Ludovico Biagi, Marco Negretti

Editor: Maria A. Brovelli





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