In a nationwide visualization interactive scenario, to ensure fast preview of large-scale vector data, iServer provides vector precache and raster precache generation capabilities for Vector Tiles Service V2. The results can be configured to the service to improve rendering efficiency. This section describes the specific configuration process and precautions.

Operation Steps

Feature Entry:

  • Service Management Home ‐> Cluster -> Tile Management Tab -> Select Service -> Specify Vector Tiles Service V2

Operation Instructions:

(1) Vector Precache Generation

Click the Generate Vector Precache Icon button after the component (e.g., vectorMap-postgres-public) on the left side of the interface to start the configuration for vector precache generation for this Vector Tiles Service V2. The details are as follows:

  • Tile Settings
    • Tile Levels: Supports selecting cache levels for tile cutting by dragging. The selectable range is 0-25, default is 7-16.
    • Tile Format: Currently only supports MVT format.
    • Tile Size: The size of each generated tile, in pixels. Currently only supports 512*512 pixel tiles.
    • Tile Extent: Used to set the geographic extent for tile generation, format like: -180, -90, 180, 90. Default is the full map extent.
    • Tile Origin: The starting coordinate point for calculating tile row and column numbers, default is the upper-left corner of the cutting extent.
  • Storage Settings
    • Storage Type: The storage method for Vector Tiles. Currently only supports geotrellisfile.
    • Storage Format: Original and Compact. When the tile storage format is Original, tile files are stored as separate image files on disk without compression, allowing direct reading. Map tiles data appears as original images in multiple folders. Compact tiles apply certain compression and encryption mechanisms to the original tile files, including two parts: an index file (*.sci) and tile data. The tile data structure uses a set of files to replace the original format, and tile data under different scale folders will be stored as a set of files (*.cf). Currently only supports Original.
    • Tile Name: The tile name, corresponding to the folder name storing the tiles, defaults to the service name. Currently not configurable.
    • Storage Path: The storage path for generated tiles, default is the default output path of the current product package (output). Currently not configurable.
  • Advanced Settings
    • Enable Scheduled Tile Cutting: Supports checking. After checking, you can set and add tile cutting time periods. The tile cutting task will only run during the allowed period, pauses outside that period, and resumes when the next allowed period starts until the task is completed.

(2) Raster Precache Generation

On the premise that the current Vector Tiles Service V2 has vector precache, you can click the Generate Raster Precache Icon button after the specified style (e.g., DLTB) under the component on the left side of the interface to configure raster precache generation for the map with that specific style in the service. The details are as follows:

  • Tile Settings
    • Tile Levels: Supports selecting cache levels for tile cutting by dragging. The selectable levels are affected by the vector precache levels; the maximum level for raster precache can only be an existing vector tiles level.
    • Tile Format: Currently only supports PNG format.
    • Tile Size: The size of each generated tile, in pixels. Provides two options: 256*256 and 512*512 pixels, default is 512*512.
    • Tile Extent: Used to set the geographic extent for tile generation, format like: -180, -90, 180, 90. Default is the full map extent.
    • Tile Origin: The starting coordinate point for calculating tile row and column numbers, default is the upper-left corner of the cutting extent.
  • Storage Settings
    • Storage Type: The storage method for raster tiles. Currently only supports geotrellisfile.
    • Storage Format: Original and Compact. When the tile storage format is Original, tile files are stored as separate image files on disk without compression, allowing direct reading. Map tiles data appears as original images in multiple folders. Compact tiles apply certain compression and encryption mechanisms to the original tile files, including two parts: an index file (*.sci) and tile data. The tile data structure uses a set of files to replace the original format, and tile data under different scale folders will be stored as a set of files (*.cf). Currently only supports Original.
    • Tile Name: The tile name, corresponding to the folder name storing the tiles. The default rule is {ServiceName_StyleName}. Currently not configurable.
    • Storage Path: The storage path for generated tiles, default is the default output path of the current product package (output). Currently not configurable.
  • Advanced Settings
    • Enable Scheduled Tile Cutting: Supports checking. After checking, you can set and add tile cutting time periods. The tile cutting task will only run during the allowed period, pauses outside that period, and resumes when the next allowed period starts until the task is completed.

View Task List

After creating a task, you can click View Task List. On the Tile Management -> Tasks page, you can see all ongoing and completed precache generation tasks on the current server, and view basic information, progress information, etc. for each task.

You can stop an ongoing task, start or delete a paused task, click the tile name in the task list to view more detailed task information, progress information, and the work progress of each scale, and restart a task to re-cut tiles.

For completed tasks, you can view the corresponding tile name, component name, duration, number of tiles, tile type, repository type, and storage location.

Monitor Tile Cutting Process

On the Tasks page, under Ongoing Tasks, click the tile name of the created precache generation task to view the task status information. This includes storage information for generating precache, tile cutting configuration information, overall task progress (dynamically displaying cutting speed and time), task time statistics, storage occupied by generated tiles (occupied storage and estimated storage required), and you can perform management operations such as "Pause", "Start", "Delete" on the task, and monitor the working status of each TileWorker in the task.

Precautions

  • Raster precache is suitable for improving performance in rendering relatively fixed-style land type patch data. If frequent dynamic styling is required during map browsing, it is recommended not to use it.
  • Raster precache is generated based on local existing vector tiles. The actual number of tiles generated equals the number of local existing vector tiles.

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