Tilesets written with --output-format=mlt could not be read back by any of
tippecanoe's own tools, which made MLT a dead end rather than a tile format.
Build the mlt-cpp decoder from the vendored maplibre-tile-spec submodule
alongside the encoder, and convert a decoded MapLibre Tile back into the
equivalent mvt_tile: geometry, feature ids, and property columns. MLT rings
come back explicitly closed, so the repeated final point becomes an MVT
closepath, and the property columns, which are held in an unordered map,
are sorted by name so that the attributes of a decoded tile come out in a
stable order.
Rather than adding an option to each tool, mvt_tile::decode() detects the
encoding and dispatches, so everywhere tippecanoe already reads a vector
tile can read MLT. An MLT tile begins with a varint layer length followed
by a varint layer tag whose only defined value is 1, while an MVT tile is
a protobuf whose only field is the repeated layer field 3, so it begins
with 0x1a followed by a layer length that can never be as short as the one
byte that would be needed to look like an MLT layer tag.
Tile directories also needed a fix: enumerate_dirtiles() recognized .mlt
file names but still recorded .pbf as the extension to read them back
with, so decoding an MLT directory failed to find any of its tiles.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LxhELiLtpUFwrPSWwTYdHG
Integrate the C++ MLT encoder from maplibre-tile-spec as a submodule.
Tiles are encoded by converting the existing mvt_tile to
mlt::Encoder::Layer and calling the encoder library directly.
New CLI flags:
--output-format=mlt Encode tiles as MLT instead of MVT
--pretessellate Pre-triangulate polygons (MLT only)
--no-mlt-feature-sort Disable within-tile Hilbert sorting (MLT only)
MLT tiles use .mlt extension in directory output and format=mlt in
mbtiles metadata. Compression and all existing flags work unchanged.
* Stabilize feature order in overzoom
* I want my sorts to be stable, please
* Revert "[ci] test in debug mode (#202)"
This reverts commit 853ada87b5.
* No need to reinitialize here
* Add an option to retain N times as many points as usual at each zoom
* Tests for point multipler with specified and guessed maxzooms
* Work in progress on inverse spatial ordering
* Fix inverse spatial feature order
* --reorder was depending on a feature index that wasn't being preserved
* Separate ordering by feature_minzoom from ordering inverse-spatially
* Add a test for the inverse spatial ordering
* Store the basezoom/droprate/multiplier decisions in tileset metadata
* Progress on adding filters to tippecanoe-overzoom
* Type promotion for comparison
* Look up the attribute value for ordering
* Add test of thinning and ordering features
* Plumb tippecanoe_decisions metadata through pmtiles
* Be careful not to put infinities in JSON
* Fix accidental dropping in what is meant to preserve sparse points
* Start distinguishing true, false, and null in expressions
* Most of the type conversions
* Add boolean conversions
* Literals and conjunctions
* Add filtering to tippecanoe-overzoom
* Add a test of filtering in overzoom
* Fix boolean conjunctions
* Handle the combination of cluster size and filtering
* Rework dot dropping to reconcile density threshold and multiplier
* Revert "Rework dot dropping to reconcile density threshold and multiplier"
This reverts commit f253a66382.
* Retain points by multiplier within each tile, not in global probability
* Test that intends to verify that the multiplier is reversible
* Get the test to detect the discrepancy
* Mark the start of multiplier clusters with a magic attribute
* Add string-contains
* Add in and ni operators
* Revert "Look up the attribute value for ordering"
This reverts commit 56bc73e49a.
* Revert "Type promotion for comparison"
This reverts commit 6f3256f5af.
* Make number formatting in tippecanoe_decisions consistent
* Revert "Add a test for the inverse spatial ordering"
This reverts commit c8047de9ab.
* Revert "Separate ordering by feature_minzoom from ordering inverse-spatially"
This reverts commit 35b19a223c.
* Revert "Fix inverse spatial feature order"
This reverts commit 5978ecdb44.
* Revert "Work in progress on inverse spatial ordering"
This reverts commit fdf230f632.
* Somehow missed the tests associated with that last revert
* Round-robin assign attributes to partials from across the multiplier
* Count the multiplier separately in each layer
* Fix distribution of accumulated attribute across multiplier features
* Update changelog, version, and docs
* Add "is null" and "isnt null" expressions
* Update interpretation of FSL expressions to pass the tests
* Test to assert that polygons are unaffected by the multiplier
* Clean up and comment
* Remove accidental unused case
* Calculate a new antimeridian-adjusted bounding box
* Add antimeridian bounding box to pmtiles, dirtiles, and tile-join
* Don't take out-of-bounds latitudes into account in the adjusted bbox
* Update changelog
* Forgot to adjust tests after the last change
* add pmtiles.hpp from github.com/protomaps/PMTiles [#10]
* tippecanoe main writes pmtiles output. [#10]
* detect output format using suffix
* after mbtiles is done writing, replace with pmtiles based on map/image tables.
* add method to write_json for writing json sub-object.
* tippecanoe-decode reads pmtiles input. [#10]
* tile-join reads and writes pmtiles. [#10]
* pmtiles test suite for decode and tile-join [#10]
* add base GitHub CI action for compiling and test suite.
* update pmtiles.hpp with z>15 fix
* Fix some ordering problems with pmtiles decode
* Pmtiles should also pass the raw tiles tests
* Eradicate spaces from tileset metadata JSON fields
* Eradicate spaces from more test fixtures
* Update more tests
* Pmtiles tests pass now too
* Remove unnecessary sort (and make indent)
* Update changelog
* The allow-existing test for pmtiles needs -o, not -e
* Declare --allow-existing to be unsupported for pmtiles.
It was always a bad idea even for mbtiles.
Co-authored-by: Brandon Liu <bdon@bdon.org>
* Progress toward making a tileset metadata structure
* Write metadata from structure to mbtiles
* Write dirtiles metadata.json from metadata structure
* Update changelog
* Working on eliminating preflighting
* Adjust for the map/images schema change
* Avoid generating duplicate tiles with the detail reduction strategy
* Do error checking if tiles in a directory can't be written
* Update changelog and version
* Revert unintentional code reordering
* Neglected to add the exit on error here
* Stop adding features to a tile if it can't possibly work
* Add --integer and --fraction options to tippecanoe-decode
* Carry the strategies field from tileset metadata through tile-join
* Update changelog
* Assign different codes to different kinds of error exits
* Change JSON objects to a union type to use less memory
* Stop storing the string representation of JSON numbers
* Restore the ability to create features with large integer attributes
* Make sure large-integer feature IDs still behave as before
* Add missing #include
* Don't preallocate as much space for arrays and objects
* Treat inability to check free disk space as a warning, not an error
* Update changelog and version
Claude