Usage

Getting started

The main purpose of the software is to generate tiles in a defined tiling system, given some options and inputs. The only mandatory option is -o for the output directory. This directory must not exist yet when you run MapTiler, to avoid overwriting existing data by mistake. As input, you can just provide the source dataset filename(s) [1].

maptiler -o output_directory input_file.ext

an example:

maptiler -o tiles map.tif

To render more files at once, just specify them one after another:

maptiler -o output_directory input1.tif input2.tif input3.tif

If you start the maptiler without arguments or with -help option, it will print all available commands:

maptiler -help

Output

The default behaviour of MapTiler is to write tiles each into its own file, under the directory structure:

output_directory/z/x/y.ext

Where z is the zoom level, and x and y tile coordinates on relevant zoom level in the tiling profile.

The produced directory structure contains also a simple HTML viewer and description of the dataset in metadata.json, compatible with mb-util and TileServer project supporting OGC WMTS standard.

MapTiler supports direct output of the rendered map tiles into an SQLite database (MBTiles or GeoPackage format). This simplifies transfer and management of the tilesets and is practical for mobile applications.

MapTiler Command Structure

_images/maptiler_command_structure.jpg

The global options apply to all input files, in other words:

Only arguments specified BEFORE the input filenames are applied to all files!

Arguments which should be applied only to a single file are specified AFTER the name of such file (for example zoom level range specific only to that file) and has higher priority then the global options.

Available output options

Tiling profile / Tile Matrix Set

A global option defining the output system of tiles - the target coordinate system, tile pixel size, etc. MapTiler comes with three predefined most popular systems and possibility to specify a custom profile.

-mercator
DEFAULT. The spherical mercator tile profile compatible with Google, Bing, Yahoo Maps, MapQuest, OpenStreetMap, and mobile maps on iOS and Android. This is the most commonly used profile. It uses coordinate system defined as EPSG:3857 or EPSG:900913. Details at: http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/.

In case you wish to use other tiling system, you must specify it as the first command on the command line. These are the alternatives:

-geodetic
WGS84 Plate Caree / Unprojected. Compatible with most existing WMS servers, OpenLayers base map.
-gearth
Tile profile specific for Google Earth according the KML SuperOverlay definition.
-custom
You can specify your own tiling system. See the appropriate section under the Advanced options chapter for more information.
-raster
Rendering raster files without a need of georeference is possible as well.
-garmin
To produce format for Garmin GPS devices, with a size 1024x1024 pixels and output to .kml file. Afterwards, pack the tiles and the .kml tiles into a .zip archive, change its extension to .kmz and save it into the device.

Example: command for producing tiles for use with Google Earth:

maptiler -gearth -o tiles map.tif
-scale value
To create high-resolution Retina / HiDPI tiles with variable scale. Retina tiles are available for each profile listed above.

Example: command for producing standard Retina tiles in mercator profile:

maptiler -mercator -scale 2.0 -o tiles@2x map.tif

Example: command for producing Retina tiles at 1.5 scale in raster profile:

maptiler -raster -scale 1.5 -o tiles-retina map.tif

Zoom levels

-zoom

This option determines which layers of the tile pyramid will be generated. Default is the “native” level as calculated from image resolution. In case you need to add additional zoom levels, you can either define them as absolute numeric values or as relative numbers to the “native” levels with prefix + and -.

Each input file can have it’s own explicit option for zoomlevels.

Example: zoom levels are automatically calculated as eg. 1 - 5

maptiler -o tiles map.tif

Example: zoom levels are explicitly set to be 3 - 5

maptiler -o tiles map.tif -zoom 3 5

Example: zoom levels are set to be 1 - 6 with relative value to native zoomlevels

maptiler -o tiles map.tif -zoom +0 +1

Tile formats

The produced tiles can be saved in one of several image format. MapTiler includes optimization of the final filesize and used number of colors (quantization), to minimize the disk size occupied by the rendered maps as well as the time necessary to transfer the maps to clients once the tiles are online.

Formats with support for transparency are:

-f png8a
DEFAULT. Paletted RGBA PNG image.
-f png or -f png32
RGBA PNG image
-f webp or -f webp32
RGBA WebP image

Non-transparent formats are:

-f jpg or -f jpeg
Progressive JPEG image in the YCbCr color space
-f png8
Paletted RGB PNG image
-f png24
RGB PNG image
-f webp24
RGB WebP image

Tile transparency or a background color

No matter what input datasets you specify, after transforming them into the tiling profile projection, MapTiler will handle them as RGBA images. The transparency can come from the image itself as an alpha channel (with support for partly transparent areas), it can be derived from a selected color (so called NODATA color), or can be just a result of the transformation with the GDAL warping algorithm - for areas without available input data.

If the tile is completely transparent it is never saved to the disk to save the storage space.

If all of the pixels are fully visible (eg. opaque, maximum alpha is 255), the alpha channel is discarded and the tile is marked as non-transparent / opaque. Otherwise the tile is marked as partly transparent with alpha.

If partly transparent tiles are saved into a tile format without support for transparency (such as JPEG specified with -f jpg option) then the background color is applied. Default background color is white (255,255,255), but you can specify your own with the option:

-bg [r] [g] [b]
The color of the background replacing transparency in the non-transparent tile formats.

For example:

maptiler -f png8 -bg 0 128 0 ...
-ignore_alpha
If your dataset contains four channels, but the forth channel is not alpha channel, you can use this option for ignore this channel.

For example:

maptiler -f png32 -ignore_alpha input_4bands.tif ...

Tile store format

-store dir|mbtiles|geopackage

This option enforces the form of storage which is used for saving the rendered tiles. Possible options are the directory (dir), the MBTiles (mbtiles) and the GeoPackage (geopackage). The default is the directory, but in case the -o parameter ends with .mbtiles or .gpkg then rendering into MBTiles or GeoPackage is selected, respectively. This option specify the store form explicitely.

Note: for more details on this subject read the section Output in the chapter Usage above.

-sparse
Skip the empty space between separate maps and don’t create empty tiles. This option can improve speed of rendering, if there are huge areas between maps. This is default option for -store dir.
-no_sparse
Fills the empty space between separate maps (if there is some) with empty tiles in background colour. This option can take longer to render and take more disk space, if there are huge areas between maps, as these have to be created. This is default option for -store mbtiles and -store geopackage.

Hybrid tile format

MapTiler allows rendering into a hybrid tile format, so that transparent tiles are using transparent format (such as PNG) and tiles without any transparency at all are saved into a different format (such as JPEG). For aerial photos overlays or other datasets this can mean significant saving of the storage. Generated files are without extensions. This is done to simplify the generated OpenLayers viewer.

Example of usage:

maptiler -f hybrid <opaque> <transparent> ...
maptiler -f hybrid jpg png8a ...

Tile quality

There are some options to specify parameters of the conversion into image formats, which can significantly reduce size of produced tiles by degrading the output.

-jpg_quality
The quality of JPEG compression. Number between 10 and 95. Default is 85.
-quant_quality
The quality of quantization. Number between 1 and 100. Default is 100.
-quant_speed

Higher speed levels disable expensive algorithms and reduce quantization precision. Speed 1 gives marginally better quality at significant CPU cost. Speed 10 has usually 5% lower quality, but is 8 times faster than speed 8. Default is 10.

If you experience issues with the visual quality of generated tiles with quantization involved try to set -quant_speed to lower values.

-webp_quality
The quality of WebP compression. Number between 1 and 100. Level 100 means lossless compression. Default is 75.
-webp_alpha_quality
The quality of WebP alpha channel compression. Number between 1 and 100. Level 100 means lossless compression. Default is 100.

Example of the rendering of a seamless map out of file map1.tif and map2.tif into tiles with internal palette with optimal colors with higher visual :

maptiler -o tiles -f png8a -quant_quality 90 -quant_speed 4 map1.tif map2.tif

Watermark

-watermark [image_file.png]
It is possible to place your own watermark over rendered tiles to protect the online maps. The file should be smaller then a size of tiles. It is placed on a random position and burned into tiles.

A nice watermark file can be easily generated online by calling the Google Chart API: http://chart.apis.google.com/chart?chst=d_text_outline&chld=FFFFFF|11|h|000000|b|%C2%A9%20ABC

By replacing ABC in the end of this url a custom text phrase can be specified. We recommend to set the transparency of such watermark file by using a Photoshop or similar tool before applying it with MapTiler.

Example of usage of the watermark:

maptiler -o tiles -watermark watermark_image.png map.tif

Advanced options

Options in the optfile

In case you have a large number of arguments to pass to maptiler, such as many input files (total amount is unlimited for maptiler), you can prepare a text file with all the arguments and call it with – optfile myarguments.txt. List of files can be easily created with ls or dir commands.

Any arguments normally passed on the command line could be part of the –optfile text file. Maptiler can combine arguments on the command line with arguments in the text file, such as:

maptiler -o output_directory --optfile myarguments.txt

Temporary directory location

During rendering, MapTiler also writes a substantial amount of data to a temporary directory. Not as much as will be in the output directory, but still. Please make sure there is enough space in the filesystem for it.

By default, the temporary directory will be created in the system default temporary location (/tmp/ on Unix-like systems, or path from the environment variable%TEMP% on Windows-like systems). You can override this with the option:

-work_dir [directory]
The location where to store temporary data during rendering. By default the system temporary directory.

Example:

maptiler -work_dir /tmp -o /mnt/data/tiles /mnt/maps/*.tif

Resampling methods

The visual quality of the output tiles is also defined by the resampling method. Selected method is used for interpolation of the values of individual pixels and it affects the sharpness vs smoothness of the produced maps.

-resampling near
Nearest neighbor resampling. Rarely makes sense for production data. Can be useful for quick testing, since it is much faster the the others.
-resampling bilinear
DEFAULT. Bilinear resampling (2x2 pixel kernel).
-resampling cubic
Cubic convolution approximation (4x4 pixel kernel).
-resampling cubic_spline
Cubic B-Spline Approximation (4x4 pixel kernel).
-resampling average
Average resampling, computes the average of all non-NODATA contributing pixels. (GDAL >= 1.10.0)
-resampling mode
Mode resampling, selects the value which appears most often of all the sampled points. (GDAL >= 1.10.0)

Resampling overviews produced by MapTiler are using average method, by default. Another possible method is Nearest neighbor.

-overviews_resampling near
Nearest neighbor overviews resampling. Mostly used for elevation maps or similar.
-overviews_resampling average
Average overviews resampling, computes the averate of all non-NODATA contributing pixels.

Defining a custom tiling profile for a specified coordinate system

MapTiler allows to define a custom system of tiles which should be rendered. Such tiling scheme, or in the terminology of OGC WMTS service the TileMatrixSet is for the maptiler defined with parameters which must follow the tile profile option: -custom.

-tiling_srs [definition]
The spatial reference system, e.g. the coordinate system in which the tiles are created. Follows the definitions known from -srs.
-tiling_bbox [minx] [miny] [maxx] [maxy]
The area which should be split into tiles defined in the tiling_srs coordinates.
-tiling_resolution [zoomlevel] [resolution]
Resolution in units of the tiling spatial reference system per pixel on the given zoom level. MapTiler will automatically compute values for all other zoom levels, each having half the resolution of the previous one.
-tiling_resolution from_output
Resolution is calculated so as to fit whole input mapset into one tile on zoom level 0 with respect to bbox, srs and tile size.
-tiling_resolution from_input
Default behaviour if resolution is not specified. Resolution is calculated so as to not supersample the largest input map with respect to bbox, srs and tile size.
-tile_size [width] [height]
The pixel dimmensions of one tile.
-tiling_centered
Tile (0, 0) is in the center of the world.

Tiling scheme - naming of tiles

MapTiler uses Google XYZ naming of tiles, by default. It supports also the TMS naming (with flipped Y axis) and QuadKey naming (known by Microsoft Bing Maps). These tiling schemes are supported only for tile store into the directory (-store dir).

-tms
OSGEO TMS (bottom-left origin), flipped Y axis as oppose to Google XYZ. This tiling scheme is defined as a standard for MBTiles.
-quadkey
Microsoft Bing QuadKey (top-left origin). MapTiler generates files named as quadkey separated into directories named as zoom level (output_directory/z/quadkey.ext). Details at https://msdn.microsoft.com/en-us/library/bb259689.aspx

Interrupt and resume long-time rendering

The long-time rendering job can be interrupted by the end-user or a system failure (power-failure, no free space on the disk). MapTiler Pro supports only simple resume mode - render process can be continued on the same computer with the same options.

-keep_unfinished
To prevent deleting the existing output tiles and temporary files created by the application.
-resume
To continue in the unfinished or interrupted rendering process. Requires the same arguments on the same computer. It skips encoding of the existing tiles. This option can be used also for the startup of the rendering process, it will automatically keep unfinished tiles.

Advanced warping arguments

The advanced warping algorithms parameters can be specified with the option:

-wo “NAME=VALUE”
The warp options. See the papszWarpOptions field at http://gdal.org/ structGDALWarpOptions.html.

Example:

maptiler -o tiles -wo "SAMPLE_GRID=YES" t.tif -wo "SOURCE_EXTRA=16"

Watch progress in a frontend

MapTiler can produce progress easily parsed in a frontend application. Simply use the first argument -progress and application output the progress on the standard output in the TSV (tabulator separated values) format: Stage TAB Percentage TAB Iteration TAB Total

Example:

maptiler -progress -o tiles map1.tif map2.tif map3.tif

Opening    16 %    1    6
Opening    33 %    2    6
Opening    50 %    3    6
Opening    66 %    4    6
Opening    83 %    5    6
Opening   100 %    6    6
Warping     0 %    0    4
Warping    25 %    1    4
Warping    50 %    2    4
Warping    75 %    3    4
Warping   100 %    4    4
Rendering   0 %    0    512
...
Rendering   100 %    512    512

Usage on a computer cluster

MapTiler can run on an MPI cluster if a cluster specific binary has been requested. If you have the MPI version, a shell wrapper to run it on a cluster is delivered as well.

A version of MapTiler utilizing Map Reduce approach and Hadoop is under development, this will replace the older MPI.

More details are provided on request.

Merge MBTiles utility

The utility allows to update a previously rendered dataset and replace a small existing area with a different newly rendered raster data. Typical use-case is fixing of a small geographic area in a large seamed dataset previously rendered by MapTiler from many input files.

The utility also extent the bounding box of the tiles - it is usable for merging two just partly overlapping maps into one bigger map covering larger extent.

Usage:

merge_mbtiles [OPTION] BASE.mbtiles DETAIL.mbtiles [DETAIL_2.mbtiles]...

Typical usage:

  1. render large dataset with MapTiler Pro - from several input files and produce large MBTiles (with JPEG or PNG tiles internally): large.mbtiles
  2. if you want to update one of the previously rendered input files in the existing dataset render just this file into MBTiles - with the PNG32 format and zoom-levels on which you want it to appear in the large dataset. Save the new small MBTiles with just one file to patch.mbtiles

Example:

merge_mbtiles large.mbtiles patch.mbtiles

Existing tiles available in both large.mbtiles and the patch.mbtiles are going to be merged. On same zoomlevels, patch.mbtiles will replace the original large.mbtiles - so the large.mbtiles will be updated in-place.

Futher options:

-P n
Set limit on defined number of cores.
-no_sparse
Fills the empty space between separate maps (if there is some) with empty tiles in background colour. This option can take longer to render, if there are huge areas between maps, as these have to be created. In case the maps overlap each other, there is no extra action involved. Default behaviour without this option does not fill the empty space between separate maps.
-reencode
This option is useful, when the 2 merged maps have different format (e.g. jpeg and png). By default, the result is a hybrid format (combination of both of them). If reencode option is used, the chosen file is encoded to the actual format (which can slow down the process).
[1]Depending on your operating system you may need to call the command differently then just maptiler, typically on Linux and Mac in actual directory as ./maptiler and on Windows as maptiler.exe.