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 Engine, 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 behavior of MapTiler Engine 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 Engine supports direct output of the rendered map tiles into an SQLite database (MBTiles or GeoPackage format). This simplifies the 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 that 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 the possibility to specify a custom profile.

-mercatorDEFAULT. 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 a coordinate system defined as EPSG:3857 or EPSG:900913. Details available here.

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

-gearthTile profile specific for Google Earth according to the KML SuperOverlay definition.-rasterRendering raster files without a need of georeferencing is also possible.-garminTo 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.-customYou 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

Example: command for producing tiles for use with Geodetic WGS84 Plate Caree:

maptiler -raster -o raster-tiles map.tif

Custom tiling presets

MapTiler Engine offers predefined custom tiling presets (custom tile grids) for Advanced customers. Each custom tiling preset has its own area coverage, some are for World, other covers only specifical States or group of States.

-preset geodeticWGS84 Plate Caree / Unprojected. Compatible with most existing WMS servers, OpenLayers base map.

Example:

maptiler -preset geodetic -o wgs84-tiles map.tif

-preset standard_gridStandard global tilegrid with a selected Coordinate system. This tiling preset keeps the original coordinate system (SRS), and cuts the input map into tiles according to the spherical Mercator tile profile. Note this is not compatible with Google Mercator profile -mercator!

Example:

maptiler -preset standard_grid -o st-grid-tiles map.tif

-preset baiduTilegrid defined for China customers. This preset cover only China region and is compatible with Baidu Maps service.

Example:

maptiler -preset baidu -o tiles map-china.tif

-preset yandexCustom tiling preset used in Russian web mapping service, compatible with Yandex.Maps. Coverage is limited to Russia and Ukraine.
Example:

maptiler -preset yandex -o tiles map-russia.tif

-preset cz_jtskNational tiling grid for Czechia and Slovakia with a precision up to 1 meter per pixel.
Example:

maptiler -preset cz_jtsk -o cz-tiles map-czechia.tif

-preset fr_rgf93Tilegrid defined for precise overlay of maps in France, using Lambert 93 conic projection.

Example:

maptiler -preset fr_rgf93 -o fr-tiles map-france.tif

-preset nl_rdnewNational tiling grid for Netherlands - Rijksdriehoekstelsel New / Amersfoort.

Example:

maptiler -preset nl_rdnew -o netherlands-map map-amsterdam.tif

-preset uk_osgb [zoom_group]National tiling grid for the United Kingdom using Ordnance Survey projection. This custom preset requires a specific zoom_group, which limits output zoom levels of this grid. Supported values with zoom levels in the bracket are: 0 (z0), 1 (z1 - z2), 2 (z3 - z6), 3 (z7 - z8), 4 (z9 - z10).

Example:

maptiler -preset uk_osgb 1 -o gb-z1 map-london.tif -zoom 1 2
maptiler -preset uk_osgb 2 -o gb-z3 map-london.tif -zoom 3 6

-preset ch_lv03 [zoom_group]Swiss national tiling grid used in Switzerland and Liechtenstein with high precision. This custom preset requires a specific zoom group, with values from 0 to 21. These values are mostly represented for the specific zoom level. Output tiles could be combined and are compatible with SwissTopo maps.

Example:

maptiler -preset ch_lv03 3 -o ch-z3 map-zurich.tif -zoom 3 3
maptiler -preset ch_lv03 4 -o ch-z4 map-zurich.tif -zoom 4 4

Note that, -zoom 3 3 is not required and it is automatically limited as defined for this zoom group.

-preset nz_nztm [zoom_group]New Zealand Geodetic Datum (NZGD2000), the official geodetic datum for New Zealand and its offshore islands. This custom preset requires a specific zoom group, which limits output zoom levels of this grid. Supported values with zoom levels in the bracket are: 0 (z0-z7), 1 (z8-z10), 2 (z11-z13), 3 (z14-z16).

Example:

maptiler -preset nz_nztm 1 -o nz-z8 map-new-zealand.tif

Retina / HiDPI tiles

-scale [value]To create high-resolution Retina / HiDPI tiles with variable floating scale. Retina tiles are available for each profile and custom tiling presets listed above. Important note, the scale value cannot exceed the max allowed tile size in pixels: 4096 x 4096. It means the max available value for -scale is 16.0.

Example: the command for producing standard Retina tiles in Mercator profile

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

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

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

Zoom levels

-zoom [min] [max]

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

Example: zoom levels are set to be 2 - 4 with relative value to native zoom levels

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

Example: zoom levels are set to 0 - 4, as an explicit minimum, relative maximum to native zoom level

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

Tile formats

The produced tiles can be saved in one of several image formats. 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 png8aDEFAULT. Paletted RGBA PNG image.-f png or -f png32RGBA PNG image-f webp or -f webp32RGBA WebP image:

Non-transparent formats are:

-f jpg or -f jpegProgressive JPEG image in the YCbCr color space-f png8Paletted RGB PNG image-f png24RGB PNG image-f webp24RGB 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. The 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_alphaIf your dataset contains four channels, but the fourth channel isn't the alpha channel, you can use this option to 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 that 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.

-sparseSkip 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.-no_sparseFills the empty space between separate maps (if there is some) with empty tiles in the background color. 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.

Setting the sparse option in GUI is in the Advanced options dialog.

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 ...

Tile quality

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.

-jpg_quality [value]The quality of JPEG compression. A number between 10 and 95. The default is 85.-quant_quality [value]The quality of quantization. A number between 1 and 100. The default is 100.-quant_speed [value]

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.

-webp_quality [value]The quality of WebP compression. A number between 1 and 100. Level 100 means lossless compression. The default is 75.-webp_alpha_quality [value]The quality of WebP alpha channel compression. A number between 1 and 100. Level 100 means lossless compression. The default is 100.-webp_losslessLossless WebP compression switch.-webp_lossyLossy WebP compression switch.-webp_preset [default|picture|photo|drawing|icon|text]WebP compression presets that use optimal algorithm parameters for a given data type.

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

-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 the size of the 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

The input files and related options

Supported input file formats

MapTiler Engine is able to open and process a large number of raster geodata formats, including GeoTIFF, Erdas Imagine, ECW, MrSID, JPEG2000, SDTS, DTED, NITF, HDF4/5, BSB/KAP, OziExplorer, etc.

The complete list of supported formats is available online here.

Spatial reference system

Practically any modern existing georeferencing coordinate system (SRS - spatial reference system, e.g. geodetic datum + map projection with parameters) is supported, which means the software can process almost any geodata you may have available from all over the world.

In case the input files contain already the definition of a user coordinate system (SRS) then MapTiler Engine is able to load it and directly use this information for the transformation of the maps. In case this information is missing in the supplied file or it is incorrect (the maptiler place the maps on a wrong location, you can still assign the information about the spatial reference system with an option:

-srs [definition]Dataset projection. Can be WKT, EPSG code in the form of ‘epsg:XXXX’, PROJ.4 string. Beware of escaping. To search for identifiers or definitions use spatialreference.org or EPSG.io.

Example of assigning the United Kingdom spatial reference OSGB to a GeoTIFF file before rendering:

maptiler -o tiles -srs EPSG:27700 map_in_osgb.tif

Transparency from a color

-nodata [r] [g] [b]This command is typically used to eliminate borders of multiple map sheets that are stitched together. You can set a specific color of the map to be considered fully transparent during rendering.

Example for removing fully black border around a map:

maptiler -o tiles map.tif -nodata 0 0 0

Georeference / calibration

Georeferencing can also be done visually using GUI or online tool.

For proper rendering of the maps the location of supplied input files in the known coordinate system (SRS) must be available. MapTiler Engine is loading the geolocation automatically from the internal headers of the input files (such as GeoTIFF) or from external supportive files (such as ESRI WorldFile) if they are available.

To enforce a custom selected georeference information or loading from external files these options are available:

-bbox [minx] [miny] [maxx] [maxy]To manually set bounds of a file in the specified spatial reference system.-geotransform [posX] [scaleX] [rotX] [posY] [rotY] [scaleY]To assign affine transformation directly. This option can be also used with its short name -gt.-georeference [path_to_file]An option to load external georeference from World File, Tab File, OziExplorer Map File or .prj file.-corners [east1] [north1] [east2] [north2] [east3] [north3]To assign affine transformation with 3 corner points: [0, 0], [width, 0], [width, height]. This option can be used with WGS84 Coordinate System (EPSG:4326) as arguments lng1 lat1 lng2 lat2 lng3 lat3, which will set up -srs EPSG:4326 for files without a specified Coordinate system.

The geolocation can be specified using three or more control points - GCP (Ground Control Point). Each GCP is defined by the position on the raster (pixel_x and pixel_y), which is associated with a georeferenced location (easting northing [elevation]). The last element (elevation) is mostly zero.

-gcp [x_pixel] [y_pixel] [easting] [northing] [elevation]To assign a ground control point. At least three control points are required. The last elemet [elevation] is optional value.-order [value]An option to set the polynomial order for transformation method of assigned GCPs. Supported orders are 0 (auto), 1 (affine), and 2 (polynomial of second order). By default, the automatic order is selected based on a number of GCP points.-tpsForce the use of Thin Plate Spline transformer based on assigned GCP points. This option cannot be used with -order. This option is recommended for more than 10 assigned GCPs.

Example for using TPS transformation with assigned GCPs:

maptiler -o tiles map.tif -srs EPSG:26712 -tps -gcp 0 0 386638.171 3999090.834 -gcp 5400 0 399627.528 3999090.834 -gcp 5400 6800 399627.528 3982553.605

Cutline (Crop)

There are two command-line options for cutline: -cutline and -cutline_proj. They specify the cutline (a clipping path) for an input image in pixels or in projected coordinates. They both expect a file name. The file can be either CSV or an OGR dataset (such as ESRI ShapeFile .shp).

From an OGR file, MapTiler Engine will load all polygons and multi-polygons from all features of the first layer.

The CSV format with pixel coordinates of nodes of a triangle, more lines will create polygon:

X1,Y1
X2,Y2
X3,Y3

-cutline [path]A pixel-based cutline is specific for each input file - so the parameter should be used after a filename (see section MapTiler Engine Command Structure).

Example of use of such a pixel-based cutline:

maptiler -o outputdir input.tif -cutline polygon.csv

-cutline_proj [path]A cutline with geo-coordinates can be used for multiple files if it is specified before the first input file.

Another example of cutline with geocoordinates stored in a .shp file (may require accompanying .prj file with a coordinate system):

maptiler -o outputdir input.tif -cutline_proj shape.shp

-cutline IGNOREIgnore embedded cutline of the file.

Example:

maptiler -o outputdir input_with_cutline.tif -cutline IGNORE

Color correction

MapTiler Engine allows you to specify several parameters in order to improve the colors of the output map. The MapTiler Desktop Pro (GUI) is able to estimate these values interactively, but you can also use the following options to specify them manually.

-color_gamma [r] [g] [b]Specify gamma correction of the individual channels, higher values result in brighter pixels (1 = unchanged).-color_contrast [contrast] [bias]Higher values of “contrast” result in bigger different between dark and light areas (0 = unchanged).

Use “bias” if you want to keep more details in the dark/light areas (0.5 = equal, <0.5 = details in light areas, >0.5 = details in dark areas)

-color_saturation [saturation]Modify saturation of the map (1 = unchanged, 0 = grayscale, >1 = colorful)

Multiple files into multiple MBTiles or Folders

MapTiler Engine is designed to produce a single merged layer from multiple input files. If you need to process multiple files and for each produce a separate tileset then batch processing is recommended.

Example:

This command processes every .tif file in a local directory and creates .mbtiles from each in the output directory. If .mbtiles is removed from the command, it produces separate directories instead.
The command differs on operating systems:

Windows

for %f in (*.tif) do ( echo %f && maptiler -o output/%f.mbtiles %f )

When used in a batch file the %f must be %%f.

Linux / macOS

for %f in *tif; do echo $f; maptiler -o output/`basename $f .tif`.mbtiles $f; done;

Advanced options

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.mtp. List of files can be easily created with ls or dir commands.

–optfile [myarguments.mtp]

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.mtp

The .mtp extension is an acronym for MapTiler Project, which can be used in MapTiler Desktop Pro GUI, see our tutorial page.

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.

Example:

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

Setting metadata for the output

It is possible to set certain metadata of the output generated with MapTiler Engine. The option is supported for all available output formats.

-name [string]Name of the generated map.-description [string]Description of the generated map.-legend [string]Legend of the generated map.-attribution [string]Attribution of the generated map, contains author or data sources.

Resampling methods

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

-resampling nearNearest neighbor resampling. Rarely makes sense for production data. Can be used for quick testing, since it is much faster than the others.-resampling bilinearDEFAULT. Bilinear resampling (2x2 pixel kernel).-resampling cubicCubic convolution approximation (4x4 pixel kernel).-resampling cubic_splineCubic B-Spline Approximation (4x4 pixel kernel).-resampling averageAverage resampling, computes the average of all non-NODATA contributing pixels. (GDAL >= 1.10.0)-resampling modeMode 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 nearNearest neighbor overviews resampling. Mostly used for elevation maps or similar.-overviews_resampling averageAverage overviews resampling, computes the average 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 that 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. This is a global option, need to be specified BEFORE the input filenames

-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_outputResolution is calculated so as to fit the whole input mapset into one tile on zoom level 0 with respect to bbox, srs, and tile size.-tiling_resolution from_inputThe 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.-tiling_centeredTile (0, 0) is in the center of the world.

Tiling scheme - the naming of tiles

MapTiler Engine uses Google XYZ naming of tiles, by default. It supports also the OSGEO TMS naming (with flipped Y-axis), QuadKey naming (known by Microsoft Bing Maps), and ZYX naming (known by Microsoft Bing Maps). These tiling schemes are supported only for tile store in the directory (-store dir). This is global option, needs to be specified BEFORE the input filenames.

-xyz or -zxyGoogle XYZ (top-left origin) naming of tiles. Folder path as output_directory/{z}/{x}/{y}.{ext}.-tmsOSGEO TMS (bottom-left origin), flipped Y-axis as oppose to Google XYZ. This tiling scheme is defined as a standard for MBTiles.-quadkeyMicrosoft 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 this Microsoft website.-zyxMicrosoft Bing ZYX (top-left origin) naming of tiles. Folder path as output_directory/{z}/{y}/{x}.{ext}.

Choose bands from multiple channels for the RGBA color model

MapTiler Engine allows choosing bands for RGB(A) color model from multiple map channels. The example is aerial images such as Sentinel 2 sources, which contains multiple spectral bands (channels) with different bandwidths, like Near Infra-Red, vegetation, cloud detection, etc. Only three classical bands are used for rendering via MapTiler Engine - RGB, Red Green, and Blue bands, to construct True Color Images. These are file options, need to be specified AFTER the name of the input file.

-b [red] -b [green] -b [blue] -b [alpha]Select an input band for the processing color model RGBA. The last part -b [alpha] is optional to select the Alpha channel. Bands are numbered from 1. This allows reordering source bands.

Example for Sentinel 2 image, where RGB bands are 4th, 3rd, and 2nd, respectively for Red Green Blue colors:

maptiler -o tiles sentinel2-image.multiband.tif -b 4 -b 3 -b 2

Example for generating red-only (1st band) image with alpha channel (4th band):

maptiler -o red-tiles image.tif -b 1 -b 1 -b 1 -b 4

-band_desc [string]Select an input band for the processing color model RGBA by the band description. The [string] parameter can be a substring of the full band description string. Usage is the same as for the -b command.

Define band data scale

It is possible to set the data scale for each of the color bands in the output generated with MapTiler Engine.

-data_scale [min] [max]Set data scale range for a band. The min parameter is optional. If omitted, the value will be set to 0. If the command is given only once, the same values will be set for all bands. To set different values for separate bands, the command has to be given 3 times (4 in case the alpha channel is used).

Example for setting all bands to range 0 - 400:

maptiler -o scaled-bands image.tif -data_scale 400

Example for setting different values for RGBA bands:

maptiler -o scaled-bands image.tif -data_scale 100 -data_scale 200 -data_scale 300 -data_scale 400

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.

-keep_unfinishedTo prevent deleting the existing output tiles and temporary files created by the application.-resumeTo 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 GDAL.

Example:

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

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 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 the Map-Reduce approach and Hadoop is under development, this will replace the older MPI.

More details are available on the 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 this tutorial article.

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

Usage:

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

Typical usage:

1. render a large dataset with MapTiler Engine - 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 the same zoom levels, patch.mbtiles will replace the original large.mbtiles - so the large.mbtiles will be updated in-place.

Further options:

-P [n]Set limit on the defined number of cores.-no_sparseFills 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.-reencodeThis 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).

Bug report

-reportThe 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 because this information helps us to identify the problem and quickly come up with a solution

Sending a bug report from the MapTiler Desktop GUI application is described here.

Vector inputs

MapTiler Engine v10.0 and higher version support rendering of Vector inputs into MVT (Mapbox Vector tile) format. Vector rendering support requires an underlying GDAL library version 2.3.0 or higher, which is limited to the native Linux distribution. Using a docker image with MapTiler Engine is recommended way for vector rendering on Linux OS. MapTiler Desktop offers GUI for Vector layers with a practical sample how-to article.

Vector input consists of one or more layers, which are rendered into the specific target layer in MVT format. Each feature of the source layer contains key=value attributes, that could be processed or renamed into the final attributes of the target layer. The following arguments are supported for the Vector input: -srs, -zoom, and -bbox, as they are described above. Other arguments are not respected for Vector rendering yet.

-layer [src_name]Select the source layer for the further processing of the vector input by the name. This argument is required for the arguments below.-target [name]Select (or create a new) target layer in the final tiles of MVT format. This is the name of the layer, which could be styled. This argument may be repeated more times to process features into a separate target layer with a different list of fields.-field [output_name] [src_name]Set the attribute field with the name src_name from the source_layer to be presented in the final target layer as an attribute key output_name. The attribute value for each feature from the source layer is copied. This argument may be repeated more times to copy more attributes.-vector_tile_size [size]Set the output vector tile size in pixels.-vector_compressUse compression of the output vector tiles.-vector_no_compressDo does not use compression of the output vector tiles.

Let assume, we have one Vector input with two source layers: lines and polygons. The source layer lines consist of the streets with these attributes keys Name, Identifier, and Main. The source layer polygons contain geometry of some buildings with attributes keys Ident, Num, and Name. We do want to create two target layers with renamed attributes.

Example

maptiler -o mymap.mbtiles \
input.shp \
-layer lines \
  -target streets \
  -field id Identifier \
  -field name Name \
  -field is_main Main \
-layer polygons \
  -target buildings \
  -field id Ident \
  -field name Name \
  -field number Num

The example above creates two new output layers: streets with attributes keys id, name, and is_main; and buildings layer with attributes keys id, name, and number.

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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.