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 Engine, to avoid overwriting existing data by mistake. As input, you can just provide the source dataset filename(s) .
￼maptiler -o output_directory input_file.ext
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:
The default behaviour of MapTiler Engine is to write tiles each into its own file, under the directory structure:
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 Engine 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 Engine Command Structure¶
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 than 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 Engine comes with these predefined most popular systems and possibility to specify a custom profile.
- 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 different tiling system, you must specify it as the first command on the command line. These are the alternatives:
- WGS84 Plate Caree / Unprojected. Compatible with most existing WMS servers, OpenLayers base map.
- Tile profile specific for Google Earth according to the KML SuperOverlay definition.
- Rendering raster files without a need of georeferencing is also possible.
- To produce the 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.
- You can specify your own tiling system. See the appropriate section under the Advanced options chapter for more information.
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
This option determines which layers of the tile pyramid will be generated. The default is the “native” level 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 its own explicit option for zoom levels.
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 zoom levels
maptiler -o tiles map.tif -zoom +0 +1
The produced tiles can be saved in one of several image format. MapTiler Engine includes optimization of the final filesize and used a 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 Engine 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 in 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.
￼maptiler -f png8 -bg 0 128 0 ...
- If your dataset contains four channels, but the fourth channel is not alpha channel, you can use this option to ignore this channel.
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 specifies the store form explicitly.
Note: for more details on this subject read the section Output in the chapter Usage above.
Setting the sparse option in GUI is described in this `how-to section`_.
- Skip the empty space between separate maps and don’t create empty tiles. This option can improve the speed of rendering if there are huge areas between maps. This is the default option for -store dir.
- Fills the empty space between separate maps (if there is some) with empty tiles in the 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 a default option for -store mbtiles and -store geopackage.
Hybrid tile format¶
MapTiler Engine allows rendering into a hybrid tile format which allows transparent tiles using transparent format (such as PNG) and tiles without any transparency at all are saved in a different format (such as JPEG). For aerial photos overlays or other datasets, this can mean a 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 ...
There are some options to specify parameters of the conversion into image formats, which can significantly reduce the size of produced tiles by degrading the output.
- The quality of JPEG compression. A number between 10 and 95. The default is 85.
- The quality of quantization. A number between 1 and 100. The default is 100.
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. The 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.
- The quality of WebP compression. A number between 1 and 100. Level 100 means lossless compression. The default is 75.
- The quality of WebP alpha channel compression. A number between 1 and 100. Level 100 means lossless compression. The default is 100.
Example of the rendering of a seamless map out of file map1.tif and map2.tif into tiles with an internal palette with optimal colors with higher visual :
￼maptiler -o tiles -f png8a -quant_quality 90 -quant_speed 4 map1.tif map2.tif
- -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 than a size of tiles. It is placed in 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 at the end of this URL a custom text phrase can be specified. We recommend setting the transparency of such watermark file by using a Photoshop or similar tool before applying it with MapTiler Engine.
Example of usage of the watermark:
￼maptiler -o tiles -watermark watermark_image.png map.tif
Options in the optfile¶
In case you have a large number of arguments to pass to MapTiler Engine, such as many input files (total amount is unlimited for MapTiler Engine or MapTiler Desktop Pro), 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 Engine 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 Engine 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.
￼maptiler -work_dir /tmp -o /mnt/data/tiles /mnt/maps/*.tif
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 used for quick testing, since it is much faster than 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 Engine are using the 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 Engine allows defining 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 Engine 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 Engine 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
- The default behavior if the 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 dimensions of one tile.
- Tile (0, 0) is in the center of the world.
Tiling scheme - naming of tiles¶
MapTiler Engine 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 in the directory (-store dir).
- OSGEO TMS (bottom-left origin), flipped Y axis as oppose to Google XYZ. This tiling scheme is defined as a standard for MBTiles.
- Microsoft Bing QuadKey (top-left origin). MapTiler Engine 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 Engine supports only simple resume mode - render process can be continued on the same computer with the same options.
- To prevent deleting the existing output tiles and temporary files created by the application.
- 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 https://gdal.org/structGDALWarpOptions.html.
￼maptiler -o tiles -wo "SAMPLE_GRID=YES" t.tif -wo "SOURCE_EXTRA=16"
Watch progress in a frontend¶
MapTiler Engine 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
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 Engine 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 Engine utilizing Map Reduce approach and Hadoop is under development, this will replace the older MPI.
More details are available on MapTiler Cluster page.
Merge MBTiles utility¶
This feature is available in MapTiler Desktop PRO and MapTiler Engine editions with an activated license only, not in MapTiler Desktop PRO Demo. Merging MBTiles in GUI is described in `how-to section`_.
The utility allows to update a previously rendered dataset and replace a small existing area with a different newly rendered raster data. The typical use-case is fixing of a small geographic area in a large seamed dataset previously rendered by MapTiler Engine from many input files.
The utility also extend the bounding box of the tiles - it is usable for merging two just partly overlapping maps into one bigger map covering larger extent.
merge_mbtiles [OPTION] BASE.mbtiles DETAIL.mbtiles [DETAIL_2.mbtiles]...
- render a large dataset with MapTiler Engine - from several input files and produce large MBTiles (with JPEG or PNG tiles internally): large.mbtiles
- 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
merge_mbtiles large.mbtiles patch.mbtiles
Existing tiles available in both large.mbtiles and the patch.mbtiles are going to be merged. On same zoom levels, patch.mbtiles will replace the original large.mbtiles - so the large.mbtiles will be updated in-place.
- -P n
- Set limit on the defined number of cores.
- Fills the empty space between separate maps (if there is some) with empty tiles in a background color. 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 behavior without this option does not fill the empty space between separate maps.
This option is useful when the 2 merged maps have a 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).
Sending a bug report from GUI is described in the `how-to section`_.
-report The argument -report generates the text report, which should be sent via the web form.
Attaching this file if you are reporting a bug is very important becuase this information helps us to identify the problem and quickly come up with a solution
|||Depending on your operating system you may need to call the command differently than just maptiler, typically on Linux and Mac in the actual directory as ./maptiler and on Windows as maptiler.exe.|