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README.md

@@ -418,6 +418,7 @@ be reduced to the maximum that can be used with the specified _maxzoom_.
    `sum`, `product`, `mean`, `max`, `min`, `concat`, or `comma`
    to specify how the named _attribute_ is accumulated onto the attribute of the same name in a feature that does survive.
    The attributes and operations may also be specified as JSON keys and values: `--accumulate-attribute='{"attr": "operation", "attr2": "operation2"}'`.
+ * `--accumulate-numeric-attributes` _prefix_: Accumulate sum, count, min, and max for all numeric attributes into new attributes with the specified _prefix_.
  * `--set-attribute` _attribute_`:`_value_: Set the value of the specified _attribute_ in each feature to the specified _value_. This is mostly useful to give an attribute in each feature an initial value for `--accumulate-attribute`.
    The attributes and values may also be specified as JSON keys and values: `--set-attribute='{"attr": value, "attr2": value}'`.
  * `-pe` or `--empty-csv-columns-are-null`: Treat empty CSV columns as nulls rather than as empty strings.
@@ -430,6 +431,7 @@ be reduced to the maximum that can be used with the specified _maxzoom_.
 
  * `-j` *filter* or `--feature-filter`=*filter*: Check features against a per-layer filter (as defined in the [Mapbox GL Style Specification](https://docs.mapbox.com/mapbox-gl-js/style-spec/#other-filter) or in a Felt filter specification still to be finalized) and only include those that match. Any features in layers that have no filter specified will be passed through. Filters for the layer `"*"` apply to all layers. The special variable `$zoom` refers to the current zoom level.
  * `-J` *filter-file* or `--feature-filter-file`=*filter-file*: Like `-j`, but read the filter from a file.
+ * `--unidecode-data` *file*: Specify transliterations that will be used when evaluating expressions, in the format from https://metacpan.org/pod/Text::Unidecode
 
 Example: to find the Natural Earth countries with low `scalerank` but high `LABELRANK`:
 
@@ -468,14 +470,16 @@ the same layer, enclose them in an `all` expression so they will all be evaluate
    compensate for the larger marker, or `-Bf`*number* to allow at most *number* features in the densest tile.
  * `--retain-points-multiplier=`_multiple_: Retain the specified multiple of points instead of just the number of points that would ordinarily be retained by the drop rate. These can be thinned out later with the `-m` option to `tippecanoe-overzoom`. The start of each cluster is marked in the feature sequence by the `tippecanoe:retain_points_multiplier_first` attribute. The `--tile-size-limit` will also be extended at low zoom levels to allow for the multiplied features.
  * `--drop-denser=`_percentage_: When dropping dots at zoom levels below the base zoom, give the specified _percentage_
-   preference to retaining points in sparse areas and dropping points in dense areas.
+   preference to retaining points in sparse areas and dropping points in dense areas. Use `--preserve-point-density-threshold` instead.
  * `--limit-base-zoom-to-maximum-zoom` or `-Pb`: Limit the guessed base zoom not to exceed the maxzoom, even if this would put more than the requested number of features in a base zoom tile.
  * `-al` or `--drop-lines`: Let "dot" dropping at lower zooms apply to lines too
  * `-ap` or `--drop-polygons`: Let "dot" dropping at lower zooms apply to polygons too
  * `-K` _distance_ or `--cluster-distance=`_distance_: Cluster points (as with `--cluster-densest-as-needed`, but without the experimental discovery process) that are approximately within _distance_ of each other. The units are tile coordinates within a nominally 256-pixel tile, so the maximum value of 255 allows only one feature per tile. Values around 10 are probably appropriate for typical marker sizes. See `--cluster-densest-as-needed` below for behavior.
  * `-k` _zoom_ or `--cluster-maxzoom=`_zoom_: Max zoom on which to cluster points if clustering is enabled.
  * `-kg` or `--cluster-maxzoom=g`: Set `--cluster-maxzoom=` to `maxzoom - 1` so that all features are visible at the maximum zoom level.
+ * `--keep-point-cluster-position`: Do not average the location of points as they are clustered.
  * `--preserve-point-density-threshold=`_level_: At the low zoom levels, do not reduce point density below the specified _level_, even if the specfied drop rate would normally call for it, so that low-density areas of the map do not appear blank. The unit is the distance between preserved points, as a fraction of the size of a tile. Values of 32 or 64 are probably appropriate for typical marker sizes.
+ * `--preserve-multiplier-density-threshold=`_level_: Preserve a minimum point density, but as `--retain-points-multiplier` features, not primary features.
 
 ### Dropping a fraction of features to keep under tile size limits
 
@@ -487,6 +491,7 @@ the same layer, enclose them in an `all` expression so they will all be evaluate
  * `-aS` or `--coalesce-fraction-as-needed`: Dynamically combine a fraction of features from each zoom level into other nearby features to keep large tiles under the 500K size limit. (Again, mostly useful for polygons.)
  * `-pd` or `--force-feature-limit`: Dynamically drop some fraction of features from large tiles to keep them under the 500K size limit. It will probably look ugly at the tile boundaries. (This is like `-ad` but applies to each tile individually, not to the entire zoom level.) You probably don't want to use this.
  * `-aC` or `--cluster-densest-as-needed`: If a tile is too large, try to reduce its size by increasing the minimum spacing between features, and leaving one placeholder feature from each group.  The remaining feature will be given a `"clustered": true` attribute to indicate that it represents a cluster, a `"point_count"` attribute to indicate the number of features that were clustered into it, and a `"sqrt_point_count"` attribute to indicate the relative width of a feature to represent the cluster. If the features being clustered are points, the representative feature will be located at the average of the original points' locations; otherwise, one of the original features will be left as the representative.
+ * `--distinguish-duplicates`: Treat sets of up to 50 exact duplicate locations as sub-layers, which will be accumulated or coalesced into other features of their own sub-layer instead of into their duplicates.
 
 ### Dropping tightly overlapping features