SQLite MBTiles Writer: Format Parameters

The tileset's name.

Sets the value of the name row in the metafile table.

Default to the basename of the filename.

A description of the layer.

Sets the value of the description row in the metafile table.

Defaults to the basename of the filename.

The layer type. Sets the value of the type row in the metafile table.

• Overlay (default): The tile data is an overlay map, so it can be placed on top of another map.
• Baselayer: The tile data is for a baselayer map, so it cannot be placed on top of another map.

The data format of the binary tile blob data stored in the tile table.

Sets the value of the format row in the metafile table if auto is not specified. If auto is specified then no data will be written to the format row in the metafile table.

If the Tile format value is set, then all tile blob data will be written in the file format that is specified.

The version of the MBTiles specification used in the MBTiles data.

Sets the value of the version row in the metafile table.

• 1.0: The minimum version of MBTiles that indicates that the metadata values for name, type, version, and description are supported.
• 1.1 (default): Indicates that the bounds and format metadata values are supported, along with all the metadata values that version 1.0 supports.

Sets the strategy used to determine the zoom level:

• Auto (default): Round the zoom level to the closest integer value when computing the resolution to determine the zoom level.
• Upper: Round the zoom level down when computing the resolution to determine the zoom level. For example, round 4.25 to 5. This will lead to oversampling.
• Lower: Round the zoom level up when computing the resolution to determine the zoom level. For example, round 4.75 to 4. This will lead to undersampling.

Determines the least-resolute zoom level to generate when Generate Zoom Levels is set to Yes.

Defaults to 0, which is the lowest possible zoom level.

Determines the resampling algorithm used:

• Bilinear (default): Use the Bilinear interpolation algorithm to construct the tile data. Calculates a pixel's value by averaging the closest 2x2 neighborhood of pixel values. This method produces a higher-quality result than Nearest Neighbor.
• Nearest-neighbor: Use the nearest-neighbor interpolation to construct the tile data. Nearest-neighbor interpolation uses the value of the nearest pixel to calculate the value of a given pixel without considering the values of pixels outside this nearest pixel range. Nearest-neighbor is the least resource-intensive, but also produces the lowest-resolution tiles.
• Cubic: Use the cubic interpolation algorithm to construct the tile data. Calculates a pixel's value by using the closest 4x4 neighborhood of pixel values.
• Cubic-spline: Use the Cubic Spline interpolation algorithm to construct the tile data. Because it calculates a pixel's value by using a spline, this results in a smaller error than linear interpolation, and the interpolation is smoother.
• Lanczos: Use the Lanczos interpolation algorithm to construct the tile data. Use Lanczos interpolation when you want to enhance or maintain local contrast; it is useful for viewing detailed features or boundaries.
• Mode: Use the Mode resampling method to construct the tile data. This is a custom resampling algorithm made by GDAL. This method will select the value which appears most often in all the sampled pixels and use that as the value for the given pixel.
• Average: Use the average resampling method to construct the tile data. This is a custom resampling algorithm made by GDAL. This method will use the average of all non-NODATA contributing pixels to compute the value of a pixel.

This option sets the PNG DEFLATE compression level.

Must be a value from 1-9. The default is 6.

This option sets the desired compression level of the output images. This is expressed as a percentage of the original file size. For example, setting a compression level of 75 means that the output image will be approximately 75% smaller (one-quarter of the size) than an uncompressed image.

Value: The level of compression that is used, from 1-100. The default is 75.

Note: Repeatedly reading and saving files may decrease the quality for this format. In addition, Workbench may not know which format data comes from, and whether it used lossy compression. If you know that source data comes from files with lossy compression, you should also set the compression level to 0. Although this compression still does not guarantee the exact copy of the source file, the output will be very close to the original.

When Tile Format is PNG8, this parameter determines if PNG8 data will use Floyd-Steinberg dithering.

• Yes: PNG8 data will be written using Floyd-Steinberg dithering.
• No (default): No dithering will be used.