Output tile format

Tiles produced by MapTiler Engine can be saved in one of several output image formats. Choosing the right one will help you minimize the disk size occupied by the rendered maps as well as optimize the data transfer between clients and the server once the tiles are served online. In this article, you will learn how to use these settings to achieve the desired results.

Output settings page

One of the steps you need to take during the rendering process is setting the parameters of the output tiles. The page looks like this:

Output tile format is one of its sections, and we’ll focus on it in this article.

Transparency

There are two different workflows you can choose from.

• If you need to produce an overlay that you’ll then present over a base map (or any other image layer for that matter) - choose the yes (map overlay) option.
• If you want to generate a base map - choose the no (base map) option.

Generating a map overlay (transparency on)

Compression

Using the Compression menu, you can choose from several output tile formats that support storing transparency information:

• PNG
• WebP
• Hybrid (jpg+png)

Size

When PNG is set as the output format, you can choose from two variants using the Size menu:

• Small (optimized) - 8-bit PNG (paletted RGBA PNG image) optimized for rendering speed and output size - this is the default setting
• Small (quantized) - 8-bit PNG (paletted RGBA PNG image)
• Large (lossless) - 32-bit PNG (color scheme RGBA, 8bit per each band).

Quality

It is a parameter passed to the compression algorithm. You can decrease its value to save space on your drive. This setting is available for the WebP tile format.

Hybrid tiles

In some situations, you might want to reduce the size of the rendered map. One obvious solution is to reduce the number of bits used to encode a pixel - choose a compressed format or get rid of the transparency channel. However, if you don’t want to sacrifice the transparency information, MapTiler Engine offers a solution to this problem - hybrid tiles. It saves some tiles with transparency and some without. You can find this setting as one of the compression formats when transparency is on.

The combination of formats provided by MapTiler Engine is Small (optimized) PNG (8-bit paletted RGBA) for transparent tiles and JPEG for non-transparent ones.

Generating a base map (transparency off)

Compression

Using the Compression menu, you can choose from several output tile formats that support storing transparency information:

• JPEG
• PNG
• WebP

Size

When PNG is set as the output format, you can choose from two variants using the Size menu:

• Small (optimized) - 8-bit PNG (paletted RGB PNG image) optimized for rendering speed and output size - this is the default setting
• Small (quantized) - 8-bit PNG (paletted RGB PNG image)
• Large (lossless) - 24-bit PNG (color scheme RGB, 8bit per each band).

Quality

It is a parameter passed to the compression algorithm. You can decrease its value to save space on your drive. This setting is available for the JPEG and WebP tile formats.

Background color

In case you need to set the background color of a map, you can use the button located in the right-hand side of the section. Clicking it will open the color picker. The chosen color will be used on all rendered tiles outside of your image.

Conclusion

This article explained the options for the output tile format available in MapTiler Engine. These include setting the compression format, enabling transparency, and choosing the background color for a base map. Also, the concept of hybrid tiles was presented.

Useful links

How to overlay an image over a map
Pick a color for transparency
Transparency of input file