Giselle
Giselle is a framework, that enables users to manage polygons of the underlying map as well as add other graphical elements such as text, points and lines with an applet from within a browser.
The system enables users to associate polygons with database data that can come either from an Oracle or a PostgreSQL database. The necessary network communication is reduced to a minimum and does
not hinder the user from being productive. Nevertheless, the Giselle tool enables users to use the benefits of remote collaboration (remote GIS layers, for instance).
These are the basic functionalities and a complete system is built using them and adding business logic which is different for every project.
Where is Giselle best used?
Giselle can be used in three main aspects. It can be used for presentation and analysis of spatial data; however its primal function is to be a topology and polygon editor.
Distributed, remote input of spatial data from several or many locations: Giselle allows the editing of spatial data through a browser as if it was a normal desktop application. It
connects via the Internet over secure connections to a centrally managed database that stays consistent and up-to-date at all times;
Intelligent viewing of maps over the Web: Giselle gives the user convenient and intuitive navigation such as zoom/pan even when temporarily offline;
Visualizing mixed data from vectorized maps and digitized photos;
Intelligent editing of topology: Giselle checks for topological constraints while editing, similar to AutoCheck functions in text editors. Topology editing can therefore be performed even by
less skilled personnel
How can Giselle help you?
- Giselle for presentation of spatial data: Giselle can display various spatial data as maps in several overlapping layers, zoom or pan them and display them on a desired scale.
Specific layers can be associated with a set of prescribed functions to be used at their display-time;
- Giselle for spatial data analysis: Both basic and advanced spatial data analyses are possible in Giselle. Users can query the spatial position of points on the displayed layers, can
measure the distance between points and the area of polygons. Advanced users can use Giselle to combine several layers of spatial data (from vector-type data about points in the map, like average
temperature, wind direction, location of archeological findings, parcel borders, field yields etc. to raster-type layers, like satellite and airplane images) to either derive new spatial concepts,
analyze them or simply obtain a figure that best illustrates the concept or hypothesis they want to test in a given area;
- Giselle as a topology editor: With (the help of) Giselle several sorts of data manipulation can be performed. The user can manage polygons (create, merge, split, reshape), edit
lines, points, database connections and perform other standard spatial data manipulation functions.
How does Giselle do it?
The following main guidelines were taken into account while designing and developing Giselle:
- The user wants to manipulate large datasets over slow data connections;
- The system should be platform independent, distributed and easy to maintain;
- The developers should concentrate on developing functionality and not on discovering workarounds for various platforms;
- The solution should rely on existing standards wherever possible;
- The solution should be able to use secure connections for communication.
Giselle’s Features and Functionality
Giselle is a software library intended for applications where spatial data together with associated alphanumeric data needs to be presented, analysed or manipulated. In Giselle, spatial data is
organised in layers. Two types of layers are supported:
- Image layers are bitmap images, where each pixel presents a rectangular area in nature. The bitmap images are accompanied with meta-information describing the geographical location of the
area depicted by the image. Image layers are mainly used as a background for displaying information from the database atop of it. Examples of this type of data are the orthophoto images of Earth’s
surface, satellite and aerial photographs in various spectra (visual, infrared), scanned maps, etc.;
- Vector layers contain data about geographical features that can be found in a given area. Features can have two dimensions (areas, delineated by polygons), one dimension (lines) or zero
dimensions (points). Examples of this type of data are utility networks, parcel borders, field yields, archaeological findings, roads, rivers, etc.
- Through configuration, vector layers can be designated as read-only, thus preventing the user from accidentally modifying them (useful for cadastral parcels, for example).
If a layer is configured to be editable, then it is possible to define from where the identifiers of the newly created polygons are to be fetched, and how the modifications to the existing polygons
are updated in the database. For example, updates can be modified so as to keep track of previous versions by maintaining a separate polygon revision history table.
Configurable layer properties are:
- Line properties, such as style, thickness and transparency;
- Shade properties, such as color and transparency;
- Text properties like label, font and rotation.
All these properties can be set by the user, specified in the configuration, or fetched from the database. For example, polygon's identifier can be shown as text, whereas polygon's code can influence
its shade for the purpose of thematic shading.
Some special properties apply only to specific types of layers, for example band configuration is applicable only for multi-band images.
Giselle Functionality
The Giselle library has a comprehensive set of functions that allow the manipulation of both spatial and alphanumeric data. This underlying functionality will allow the JIS to undertake functions
such as:
- Maintain administrative boundaries;
- Maintain cadastral maps;
- Maintain buildings, apartments and units;
- Maintain parcels, property rights and their history;
- Maintain physical and legal persons;
- Maintain and conduct Cadastre and Land Registry process;
- Maintain process documents.
The requirements of these functions shall be defined in the requirements and analysis phase of the project. Listed below are some examples of the types of functions that are built into Giselle.
Presentation functions of Giselle include:
- Simultaneous display of overlapping GIS data layers;
- Upper layers are transparent, so that the lower layers are not obscured;
- Support for display of vector data layers;
- Support for display of image data layers;
- Ability to set visibility and ordering of layers, based on configuration settings or user actions;
- Configurable data sources for layers. Data can come from local or network files, spatial databases, or from GIS servers;
- Zoom to full extent, to window, zoom in/out, next/previous zoom level, zoom to a specified scale;
- Pan to specified coordinates, pan to the clicked point;
- Print and print preview.
Among analysis functions of Giselle are:
- Area and distance measurement;
- Feature attribute queries;
- Combining of several layers of spatial data to derive new spatial concepts, analyze them or simply obtain a figure that best illustrates the concept or hypothesis that is to be tested in a given
area.
Editing functions of Giselle allow the user to perform the following actions:
- Reshaping of existing polygons;
- Joining existing polygons;
- Creation of new polygons;
- Changing attributes of a feature.
Before these functions are executed, affected polygons are locked in the database to ensure transactional integrity in multi-user scenarios. For example, when a user starts reshaping a polygon, the
application locks the polygon and its neighbours, preventing other users to make any changes before the first user is done.
Before these functions are executed, affected polygons are locked in the database to ensure transactional integrity in multi-user scenarios. For example, when a user starts reshaping a polygon, the
application locks the polygon and its neighbours, preventing other users to make any changes before the first user is done.
Add and Reshape functions are fully aware of topology rules, i.e., the polygons must neither overlap, nor leave out any unallocated area in their midst. While a border on a polygon is being edited,
all neighbouring polygons are also affected. These rules are a part of the application’s user interface, so the end user doesn't need to worry about them.
Application-specific rules that are enforced during editing may be configured as well. For example, polygon of a specific code could only be allowed to exceed a specified area, a vertex of a polygon
could be required to lie inside/outside a polygon from some other layer and so on.
While using adding or reshaping functions, other layers could be used for snapping to a vertex or to a nearest line, regardless of whether layer data is available locally or fetched from a server.
When editing is done, the database table is populated with the new polygon geometry and with extra information like polygon area, perimeter, number of points, etc., making subsequent data querying
and analysis much faster and simpler.
Technical Background
Deployment Requirements of Giselle
Giselle Architecture
Interoperability
Benefits of using Giselle
Giselle was carefully designed and developed by bearing in mind that all levels of involved corporate teams must benefit from its usage. The following sections explain how each of these levels
benefit from Giselle.
Benefits for decision makers
The aim of decision makers is to provide for a corporate environment, in which the work will be effective, profitable and comfortable. For them Giselle is the GIS tool of choice: it has a competitive
market price, is easy to introduce into the work process and has reliable support from the developers. Giselle is compliant with the standards of the field (OGC, XML, CORBA, Web services) and can
therefore be easily integrated with existing systems or even replace them.
Benefits for the users
The Giselle system was designed on basis of several years of experience and with in-depth understanding of user’s needs. Experience shows that customers like the idea of having a web-browser-driven
spatial data manipulation tool, as they are comfortable with everyday use of browsers. No effort is required to install Giselle - it is available from anywhere, yet it keeps its behavior and other
user configurable settings as they are stored on a server. The fact that data manipulation and validation functionality is integrated in a client has a consequence that the user always manipulates
the correct topology. With Giselle there is no need for supplemental data validation and correction of gaps or overlaps between the manipulated polygons, therefore a great deal of time is
saved.
Benefits for the system administrators
As the client side of Giselle is a web-browser driven application, it can be easily maintained even on the largest distributed systems: deployment, administration and maintenance can be done on a
server. This saves a lot of time to system administrators. Powerful configuration tools also enable them to easily adapt the tool to particular needs of specific users.
Benefits for the developers
The main advantage for the developers of Giselle and the systems using it is a modular and configurable component model used to design applications within Giselle. The developers can use a large
repository of components, such as views, layers, toolbars, menus and similar to quickly and efficiently combine them together into a user-adapted application.
References
Ministry Of Agriculture, Forestry and Food, Republic of Slovenia (MAFF)
Ministry of Environment and Spatial Planning
The Environmental Agency (EA)
- Water Agreements, 2006
- Concession Granting, 2006
- Inventory of Gas Emiisions, 2006-2007
The Surveying and Mapping Authority of the Republic of Slovenia
- Calibration of models for real estate evaluation
- Real estate value assignment process
- Process for managing complaints and remarks
Front page |
Technical Background |
Deployment Requirements |
Giselle Architecture |
Interoperability
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