- Industry solutions
The program for creating pyramids of tiles (ImageryCreator)
The program is designed to create a complete set of image fragments of maps of specified sizes by the selected scale series in the format PNG, JPEG, PNG8.
The purpose of formation of a set of rasters is to accelerate displaying the maps containing a large number of objects (over 1 000 000), in WEB-applications. Acceleration of displaying is achieved by a caching method: displaying an area of a vector map is substituted onto the displaying the area of pre-built raster.
Input data of the program are:
Output data of the program are:
Upon completion of process the nested catalog of a map … \Images\ contains the built tiles.
For starting the program it is necessary to download the file ImageryCreator.exe. After opening the main form of the application to open a map (file with extension MAP or SIT) in the menu the File - Open map. Map opening is carried out with a delay (from 1 till 5 seconds). During this moment there are performed a calculation of the sizes of raster maps (in megabytes) and a request of the free space on the disk in the map catalog (for placing the raster maps).
The window the Scales list is automatically filled with scales from the general scale range from 1: 1 to 1: 250 000 000.
According to the base scale of the main map the average scale of the scales list of rasters is set. Other scales are selected from the total scale range (from the average up to 50-fold increase and decrease of the denominator of average scale).
Formation of rasters will be carried out by the marked strings of the scales list. By default there is marked the base scale of the main map and strings of the scales list of raster maps of larger scale, with increase in 10 times. At change of composition of selected strings of the list the calculation of a required disk space (in megabytes) is carried out. At insufficient free space on the hard disk the field the Available memory size is highlighted in red color.
Starting the process of rasters formation is carried out by the Run button. By pressing the Break button (during execution) the process stop is carried out. During execution the number of processed scales can be changed.
Process of forming the raster maps of great volume (more than 10 gigabytes) can occupy a lot of time (from one hour and more). Therefore during execution the calculation of runtime is made. Calculation of runtime is made upon termination of recording the first 500 megabytes of raster data (from 4 till 10 minutes from the process beginning) and is refined up to the process completion. Difference of actual runtime from the primary estimated runtime usually does not exceed 20 percent. Upon termination of process in the nested catalog the constructed rasters (tiles) are contained.
Figure 4 shows the moment of the completion of forming a raster map of Russia, of the base scale 1: 25 000, which occupies in a vector kind 5.7 GB in SXF format. Formation of rasters was carried out in the scale from 1: 1 000 000 to 1: 50 000, containing 60 million objects on 87 sheets, with the sizes of rasters in uncompressed kind not more than 2.7 GB. 46 matrixes of elevations in total volume 9.35 GB have been added to the main map. Creation of rasters was done with the enabled functions of anti-aliasing, shadows and the mode «Printer view» on the computer of the following configuration:
Time of formation of rasters - 1 day 20 hours. In total it is created about 1 200 000 000 tiles in png format, with the sizes of each tile of 256*256 pixels, total volume of files in 4,5 TB.
If necessary to the basic map the additional user maps (files with SIT extension), files of projects MPT, rasters, matrixes can be added. Adding of additional user maps is carried out at a choice of the menu the File - Add a map or the File - View - Data list (fig. 5). Before rasterization of a vector map there is a possibility of preliminary customizing a display of map objects for each scale, for example in the classifier editor or the program the GIS Panorama.
Preliminary customization of the data makes a raster's map more evident and convenient for perception. If necessary of disabling some layers or types of objects the customization of maps contents (the basic and additional) can be executed. Customization of maps contents is carried out when you select File - View - Map contents. There is a possibility of displaying shadows by matrixes of elevations for the pseudo-volume graphics (for mountain terrain). File - View - Data list - Matrix Bookmark - Properties button - Matrix image - Only shadows. At formation of tiles the functions of anti-aliasing for linear objects are used. For improvement of displaying the vector data there is a printer mode, View - Map image - Printer.
Interface language (Russian, English) can be changed in the menu File - View. Selected interface language is stored in the file ImageryCreator.INI. At restart of the program the interface language is restored. At a choice of the menu the Help - Call of reference the form the Reference is opened containing the description of the application's work. For specifying the size of output raster PNG it is necessary to change value in the field the element size. By default it is equal to 256 pixels. For change of a palette of a map, it is necessary to establish the colors used on a map: the File - View - Setup colors.