Introduction

Create Map caches for 2D maps to optimize map browsing effects.

Basic Steps

1. On the Map tab, in the Mapping group, click Single-task to open "Map Cache Build Mode (Single Task)" dialog box. In the box, there are three modes: New Map Cache, Update/Append Cache File, Resume/Restore Cache File.
2. Click "Next" to open "Single-task: Generate Map Cache" dialog box.

Figure: The Create Map Cache dialog box

3. Following parameters are needed setting.
Scales and configuration files

The toolbar sets the scale, and imports/exports cache files.

Scale: It is used to set the map cache scale, such as the 1:1000000. It supports to calculate automatically, and users' settings.

Caption: It is ued to set the alias of the current scale. When creating the scale, this caption will be the name of the cache folder. The default uses the denominator of corresponding scale.

Toolbar: The tools to set the map scale.

• button: Used to select methods for adding scales, including Add Scale and Default Scale.
  • button: Add scales needed. If there is no scale in the dialog box, the first scale added will be the current scale of the map. If you select the last scale in the list, the added scale will be twice of the previous scale. If the selected scale is not the last one in the list, the added scale will be half of the selected scale and the next scale.
  •  Restore the scale. The system will offer a proper scale.
•  Select all scales in the list.
•  Inverse select scales in the list.
•  Remove scales.
• When the cache version is 5.0, and the Tiling Mode is Global, all scales will be listed. Users can check the scales they need.

The Global is similar to the 3D map cache in the scene cache.

•  Import map cache configuration file (*.sci).
•  Export current settings to a configuration file (*.sci).

Config File (*.sci) saves the scales and other parameters. When users update and append the caches, they can import the original config file.

• Click the Import button, then you can import the *.xml file into the list.
• Click the Export button, then you can export the scale to the *.xml file. The scale file exported from the map cache can be used with the scale files in Tools of Mapping for Scales.
Basic settings

Output Settings

• Version:

  Cache version is used to set the map cache versions. The version of caches must match server's version for publishing service. There are six versions in system.

  Only when the version is 5.0, the "Tiling Mode" is available. The Tiling Mode includes: Local and Global. And Global mode is for generating 3D caches which can be added into a scene. Default is Local mode.

  • 2.0 is IS .NET cache scheme, suit for SuperMap IS .NET 6.0 or later.
  • 2.1 is a new IS .NET cache scheme, suit for SuperMap IS .NET 6 SP2 or later.
  • 3.0 is iServer 2.0 cache scheme, suit for SuperMap iServer Java 2008 or later.
  • 3.1 is a new iServer 2.0 cache scheme, suit for SuperMap iServer Java 2008 SP2 or later.
  • 4.0 is iServer 6R cache scheme, suit for SuperMap iServer Java 6R or later.
  • 5.0 is a new iServer 6R cache scheme, suit for SuperMap iServer Java 6R(2012) SP1 or later versions.

  Figure: Select a version

• Tiling Mode: Only when the version is 5.0, the "Tiling Mode" is available. The Tiling Mode includes: Local and Global. Note: The Global mode is not available unless the coordinate system of map is WGS 1984.
• Tile Type: Includes two types: raster tiles and vector tiles. For first type, the generated tiles are raster images with higher display efficiency and occupying more server's space. For vector tiles, the amount of data is little, and the resources occupying a server are less, while transfer is more convenient and display is more agile.
• Format: The storage types of cache images. 6 kinds of formats are supported, including: PNG, DXTZ, GIF, JPG, JPG-PNG and PNG 8. Default is JPG. Cache version 5.0 supports JPG and PNG 8.

  When the formats of tiles are both JPG and PNG, the program will determime which format will be used according to whether there are some invalid pixels (without any contents). If a tile includes invalid data, its format is PNG, otherwise, its format is JPG. The usage of mixed formats can reduce the size of cache data to decrease time of downloading data.

  PNG 8 supports only 256 colors and it is usally smaller in size, but it doesn't allow background transparent.

• Transparent: If a map has a background color, when you check Transparent, the background will become transparent.
• Tile Size: Sets sampling size of every cache block file to be generated. Its unit is pixel. 6 kinds of sizes are provided for you, including 2048*2048, 1024*1024, 512*512, 256*256, 128*128, 64*64, and default is 256#256.
• Compression: The percent of compressing cache image. It ranges from 0 to 100 and default is 75. There is no relationship between the compression and storage types of caches, but for different types of images, compression ratios supported are also different.
  • The settings of compression are not supported if the types of images are DXTZ or GIF.
  • The range of compression ratio is (0,90] if types of images are PNG, PNG8, JPG_PNG.
  • The range of compression ratio is [10,100] if the image format is JPG.

Cache Path

• Cache Name: The root directory of the cache.
• Cache Path: The network or local path to save the tiles.

Output Settings

• Storage Type: Compact, Original and MongoDB storage types are provided.

  The Compact storage type compresses and encrypts the data when caching in certain mechanism, while the Original type keeps the original information. MongoDB type saves the generated cache slice files in a distributed format into the server database. For more contents about storage types, please consult Storage types of map caches.

• User Password: When the storage type is set to "Compact", you can set the password for the map cache to ensure data security. The password needed to be input for loading the cache.

• Filter layers with selected objects: When using the way of "Select Object" in the Bounds Settings, you can determine the generated cache bounds based on the bounds of the selected object. Check the check box to filter the layer which the objects are on when the application is generating the map cache. This feature is only available if there are multiple layers in the map.
Bounds Settings

Figure: Generating Map Cache Dialog Box

• The Cache Extent section is used to set the geographical extent for map cache creation. You can set the Caching Extent through:
  • Click Full to set the full extent of the map as the cache extent. The extent will be displayed in the Top, Bottom, Right and Left text boxes.
  • Click Current to set the current view extent as the cache extent.
  • The Select button is only active if there are open maps in the workspace. Click Select to select objects as the cache extent. If you want to select multiple objects, press Shift and select the object one by one, and right click mouse to finishing the operation.
  • Click Copy button to copy current range, and click Paste button to paste the copied range to current range.
• Index Extent is the basis for the map cache tile segmentation rule. When the index range is determined, the tile segmentation rules is determined. The map caches with the same index range can be merged. Five options are provided for you to set the index extent: Full, Current, Draw and Extent, Copy and Paste. Please refer to the introduction to how to select the extent in the Cache Extent section.
  Note: Only map cache with the same index range can be appended successfully.
4. After the settings are finished, click OK. The generated file(*.sci) is a configuration file for cache. You can open the file through the way about how to open a datasource.

Note

1. There must be maps in the current workspace.
2. For setting the cache bounds, please notice that:
   • When using the function of Select Object, if the layer to be selected isn't allowed to select, you can directly set the layer editable through the Layer Manager, and then select the object.
   • Right click the mouse and the Create Map Cache dialog box will display again. And then close the dialog box for necessary settings.
3. While creating map cache, the application will ask you to turn off flow display first. The Output Window will list layers with flow display turned on, you need to turn off flow display manually.
4. About the picture background transparent description:
   • When the cache version is 2.0, 3.0, 3.1 or 4.0, if the map which will be used to generate cache doesn't use antialiasing and the format of generated image is .png, the effect of background transparent is supported when the cache is opened as a datasource.
   • When the cache version is 2.0, 3.0, 3.1 or 4.0, if the format of generated image is .gif, the effect of background transparent isn't supported when the cache is opened as a datasource.
   • When the cache version is 5.0, the effect of background transparent is supported for all generated cache.
   • When the cache is loaded into the scene for displaying, the effect of background transparent is supported for each version.

It isn't recommended that rotate the cache map. If you want to a better rotation effect, you'd better to rotate first, then create the cache file.

Remarks

For global tiling rules, please refer to Cache Directory and Structure of Other Levels.