|GIS Server 2011|
GIS Server 2011 - is the program, designed to ensure remote access to cartographic data for users of the programs GIS Map 2011, Panorama Editor, GIS Navigator 2011, GIS Panorama Mini 2011 and other programs developed in an environment GIS ToolKit version 11 or newer
The server provides remote access to the vector maps, rasters and matrixes. Connection with a server is installed under TCP\IP protocol with use of the mechanism of sockets.
Between the client and a server the binary data are transferred - coordinates of objects, attributes, blocks of data of rasters and matrixes. Therefore for normal work the high-speed connection of a client and a server is required, for example, by network Ethernet 100 Mbit\sec.
Placement of data on a server provides protection of data against illegal copying and change, increases the rate of data sharing. The user chooses for work the data by their conditional names (alias). Vector maps can be opened for viewing or for viewing and editing. Rasters and matrixes are accessible only to viewing and an execution of calculations. Besides, all data can be closed or opened for copying from a server - into exchange formats, into the clipboard or onto other maps.
GIS Server 2011 program can be installed on any computer in a local network with with OC Windows XP, Windows 2003 (2000), Windows Vista and higher. Program GIS Server 20 08 for Linux is applied to OS of Linux type.
For each client it is allocated within the limits of 1,5 Mb of RAM . The number of the open vector maps, rasters and matrixes essentially does not influence the size of allocated memory. To connect 100 clients it is necessary for the application of the order of 1, 5 GB of RAM on a computer where the GIS Server 2011 is installed. The number of connected clients is not limited in program.
GIS Administrator 2011 - the program intended for customizing the work parameters of the GIS Server 2011. The program allows you to specify a list of users, a list of data and their properties, which allows you to customize GIS Server 2011 for the specific application. The list of accessible data is formed for each group of users the own one. Access of the user to data is made by the user name and password.
In the program the GIS Administrator 2011 the project is presented in the form of a tree, which includes:
The list of users, the list of data and their properties are stored on a server in a file of parameters GISSERVER.XML. Creating and editing a file of parameters is carried out by the administrator of a server. Lists of passwords are stored in a file of parameters in the ciphered form by algorithm MD5.
For customizing the project it is recommended at first to select the cartographical information. The user can create hierarchically arranged tree of maps, rasters and matrixes, to unite data into sections. For maps, rasters and matrixes the user assigns conventional names (aliases) for work.
All users of the system should be included in the list of users with the appoint ment of login and the password. In order to limit access to data the administrator must maintain a list of user groups. For each group the rights for editing, viewing and copying of data are assigned. User rights are determined by group to which he belongs.
Evaluation of performance
Test for reading data
In assessing the performance of different ways to access data the following results have been received.As a server and clients the computers were used with processor Pentium 4 - 3 GHz, 1 GB RAM, running Windows XP. Network with a capacity of 100 Mbit\sec (12 MB\s).Map in the size of 113 Mb , consisting of 40 sheets and 876 433 objects (territory of the Russian Federation of scale 1 : 1 000 000).The application task was executed which reads from a map into the application's memory consistently all objects of a map. Operation was performed in the cycle 10 times.
The map opened in 6 ways.
1 way - directly from the GIS Map 2011 on the server. At one-time reading all data there were spent - 1.7 seconds (66 MB\s). For the information - the full map display took less than 1 second (all map in a window, all objects are fingered , display of objects with generalization - small objects are ignored , their metrics is not read).
2 way - from the GIS Map 20 11 through GIS Server 2011, when both programs are running on the server. At one-time reading all data it is spent - 3,6 seconds (31 MB\s ). For the information - the full map display took less than 4 seconds (all map in a window, display of objects with generalization - small objects are ignored ).
3 way - from GIS Map 20 11 through GIS Server 2011 when programs are connected via a local area network (Client-Server). At one-time reading all data it is spent - 12,5 seconds (9 MB\s ). For the information - the full map display on the client took less than 10 seconds (actually the process of display will take the fixed time for all ways; in this case - less than a second to time of access to necessary data).
4 way - from the GIS Map 20 11 by direct opening a map through a local area network on a server (File-Server). At one-time reading all data it is spent - 12 ,5 seconds (9 MB\s ). For the information - the full map display on the client took about 10 seconds.
5 way - from the GIS Map 20 11 through the GIS Server 2011 when programs are connected via a local area network (Client-Server), and the procedure was launched simultaneously on 2 different clients. At one-time reading all data it is spent - 20,7 seconds (11 MB\s ) - identical on two clients.
6 way - from the GIS Map 20 11 by direct opening a map through a local area network on a server (File-Server), and the procedure was launched simultaneously on 2 different clients. At one-time reading all data it is spent - 20,9 seconds and 22,2 seconds (11 MB\s ) - a miscellaneous on two clients.
Conclusion: the data access through the GIS Server 2011, at least, does not worsen performance when working with a map in a local area network, providing thus protection of data against illegal copying, editing and viewing. A significant impact on productivity has the throughput of network equipment. In this case potentially it is possible to raise speed of procedure execution from 12,5 seconds to 4,5 seconds at transition to a network of 1 Gbit - in 2,7 times ((12,5 - 3,6)/10 + 3,6 = 4,5).
At increasing a number of users the access time increases linearly proportionally to number of the users simultaneously accessing data, when server works on a single -processor computer. Use of multiprocessor computers will allow additionally to reduce time of access for simultaneous access to data, as work of each client is provided by an autonomous stream on a server .
Test for reading data
At evaluating performance of editing data at different ways of accessing data the following results have been received.
As a server and clients the computers were used with processor Pentium 4 - 3 GHz, 1 GB RAM, running Windows XP. Network with a capacity of 100 Mbit\sec (12 MB\s). On a server the version GIS Server 1.1.1 was installed, on the client - the GIS Map 2008 version 10.1.2. Version of the software on the client and the north should be consistent, since the communication protocol may be supplemented by new commands. At versions mismatching, the warning will be about necessity to update the version of the program (available for download on http://www.gisinfo.net/download/download.htm).
The map was opened in 5 ways - Exclusive access (menu Settings \ Offline work with maps), Shared access (the parameter Offline work with maps is disabled), connection through the GIS Server on the same computer with the client (to eliminate the influence of the network), connection through the GIS Server on a local area network, access on a local area network in the mode File-Server.
For work of the user with a map which simultaneously with him nobody digitizes, Exclusive access is more preferable. In this case speed of an execution of all operations is maximal. Other users can get access to a map only for reading (thus, in properties of a map for all other users who opened a map during this moment, the read-only attribute is retained, which at the further opening of the map for editing must be cancelled in the Data List \ Properties \ Editing; otherwise the map as before will open read-only).
For collaborative work with the map the access is usually in the mode the File-Server over a local network or via the GIS Server . The overall speed of operations execution is influenced essentially the speed of data transmission over the network. For its estimation an access was carried out both in the placement of maps on a computer of the client, and on the remote computer.
In the first test there was performed the moving of objects on a map Podolsk - 21 993 objects (3,4 Mb) and then a cancelling of operation . Results of an execution of operations are listed in the table:
In the second test the mapping of 2 000 objects in total amount of 32 Mb and a cancelling of operation was carried out. Results of operations execution are listed in the table:
Conclusion: editing a map through the GIS Server for group operations is carried out faster in 3-5 times, than access via the File-Server (opening of a map on a local area network).Acceleration is achieved due to the moving some operations on editing a map and conducting the log of transactions on a server.
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