# Optimized Transforms
VegaFusion supports optimizing a subset of [Vega's transforms](https://vega.github.io/vega/docs/transforms/). Below is a detailed breakdown of transform support status.
:::{note}
When a Vega spec includes unsupported transforms, these transforms will be included in the client Vega spec for evaluation by the standard Vega library in the browser. See [How it works](../about/how_it_works.md) for more details.
:::
> **Key**:
> - ✅: Full optimization support for the transform and all its options
> - 🟡: Partial optimization support for the transform with limitations
> - ❌: Transform is not currently eligible for optimization
## Basic Transforms
:::{list-table}
:header-rows: 1
:widths: 40 10 100
* - Transform
- Status
- Details
* - [aggregate](https://vega.github.io/vega/docs/transforms/aggregate/)
- 🟡
- :::{dropdown} More Info
Supported aggregate `ops`:
- `count`
- `valid`
- `missing`
- `distinct`
- `sum`
- `mean` or `average`
- `variance`
- `variancep`
- `stdev`
- `stdevp`
- `median`
- `q1`
- `q3`
- `min`
- `max`
Unsupported aggregate `ops`:
- `product`
- `ci0`
- `ci1`
- `stderr`
- `argmin`
- `argmax`
The `cross`, `drop`, and `key` options are not yet supported.
:::
* - [formula](https://vega.github.io/vega/docs/transforms/formula/)
- ✅
- :::{dropdown} More Info
See [optimized expressions](./optimized_expressions.md) for details on supported
expression features that may be used in the `expr` field.
:::
* - [window](https://vega.github.io/vega/docs/transforms/window/)
- 🟡
- :::{dropdown} More Info
Supported window operations:
- Ranking operations:
- `row_number`
- `rank`
- `dense_rank`
- `percent_rank`
- `cume_dist`
- Value operations:
- `first_value`
- `last_value`
- All supported aggregate transform ops
Not yet supported:
- `ntile`
- `lag`/`lead`
- `nth_value`
- `prev_value`/`next_value`
All frame specifications and peer handling options are supported.
:::
* - [lookup](https://vega.github.io/vega/docs/transforms/lookup/)
- ❌
-
* - [bin](https://vega.github.io/vega/docs/transforms/bin/)
- ✅
- :::{dropdown} More Info
`interval` option ignored and both bin edges are always included.
:::
* - [collect](https://vega.github.io/vega/docs/transforms/collect/)
- ✅
-
* - [extent](https://vega.github.io/vega/docs/transforms/extent/)
- ✅
-
* - [filter](https://vega.github.io/vega/docs/transforms/filter/)
- ✅
- :::{dropdown} More Info
See [optimized expressions](./optimized_expressions.md) for details on supported
expression features that may be used in the `expr` field.
:::
* - [flatten](https://vega.github.io/vega/docs/transforms/flatten/)
- ❌
- :::{dropdown} More Info
May be possible in the future with DataFusion's
[unnest](https://github.com/apache/datafusion/pull/10044) transform.
:::
* - [fold](https://vega.github.io/vega/docs/transforms/fold/)
- ✅
-
* - [project](https://vega.github.io/vega/docs/transforms/project/)
- ✅
-
* - [sequence](https://vega.github.io/vega/docs/transforms/sequence/)
- ✅
-
* - [timeunit](https://vega.github.io/vega/docs/transforms/timeunit/)
- 🟡
- :::{dropdown} More Info
`interval` option ignored and both bin edges are always included.
`step`, `extent`, and `maxbins` options are not supported, so `units` must be
provided.
:::
* - [countpattern](https://vega.github.io/vega/docs/transforms/countpattern/)
- ❌
-
* - [cross](https://vega.github.io/vega/docs/transforms/cross/)
- ❌
-
* - [density](https://vega.github.io/vega/docs/transforms/density/)
- ❌
-
* - [dotbin](https://vega.github.io/vega/docs/transforms/dotbin/)
- ❌
-
* - [identifier](https://vega.github.io/vega/docs/transforms/identifier/)
- ✅
-
* - [impute](https://vega.github.io/vega/docs/transforms/impute/)
- 🟡
- :::{dropdown} More Info
Supported:
- `field` - Field to impute
- `key` - Unique identifier field
- `value` - Custom value for imputation
- `groupby` - Group-based imputation
Unsupported:
- `method` parameter with options other than `value`
- `keyvals` array for custom key values
:::
* - [kde](https://vega.github.io/vega/docs/transforms/kde/)
- ❌
-
* - [loess](https://vega.github.io/vega/docs/transforms/loess/)
- ❌
-
* - [pivot](https://vega.github.io/vega/docs/transforms/pivot/)
- ✅
-
* - [quantile](https://vega.github.io/vega/docs/transforms/quantile/)
- ❌
-
* - [regression](https://vega.github.io/vega/docs/transforms/regression/)
- ❌
-
* - [sample](https://vega.github.io/vega/docs/transforms/sample/)
- ❌
-
:::
## Geographic and Spatial Transforms
:::{list-table}
:header-rows: 1
:widths: 20 10 100
* - Transform
- Status
- Details
* - [contour](https://vega.github.io/vega/docs/transforms/contour/)
- ❌
-
* - [geojson](https://vega.github.io/vega/docs/transforms/geojson/)
- ❌
-
* - [geopath](https://vega.github.io/vega/docs/transforms/geopath/)
- ❌
-
* - [geopoint](https://vega.github.io/vega/docs/transforms/geopoint/)
- ❌
-
* - [geoshape](https://vega.github.io/vega/docs/transforms/geoshape/)
- ❌
-
* - [graticule](https://vega.github.io/vega/docs/transforms/graticule/)
- ❌
-
* - [heatmap](https://vega.github.io/vega/docs/transforms/heatmap/)
- ❌
-
* - [isocontour](https://vega.github.io/vega/docs/transforms/isocontour/)
- ❌
-
* - [kde2d](https://vega.github.io/vega/docs/transforms/kde2d/)
- ❌
-
:::
## Layout Transforms
:::{list-table}
:header-rows: 1
:widths: 20 10 100
* - Transform
- Status
- Details
* - [stack](https://vega.github.io/vega/docs/transforms/stack/)
- ✅
-
* - [force](https://vega.github.io/vega/docs/transforms/force/)
- ❌
-
* - [label](https://vega.github.io/vega/docs/transforms/label/)
- ❌
-
* - [linkpath](https://vega.github.io/vega/docs/transforms/linkpath/)
- ❌
-
* - [pie](https://vega.github.io/vega/docs/transforms/pie/)
- ❌
-
* - [voronoi](https://vega.github.io/vega/docs/transforms/voronoi/)
- ❌
-
* - [wordcloud](https://vega.github.io/vega/docs/transforms/wordcloud/)
- ❌
-
:::
## Hierarchy Transforms
:::{list-table}
:header-rows: 1
:widths: 20 10 100
* - Transform
- Status
- Details
* - [nest](https://vega.github.io/vega/docs/transforms/nest/)
- ❌
-
* - [stratify](https://vega.github.io/vega/docs/transforms/stratify/)
- ❌
-
* - [treelinks](https://vega.github.io/vega/docs/transforms/treelinks/)
- ❌
-
* - [pack](https://vega.github.io/vega/docs/transforms/pack/)
- ❌
-
* - [partition](https://vega.github.io/vega/docs/transforms/partition/)
- ❌
-
* - [tree](https://vega.github.io/vega/docs/transforms/tree/)
- ❌
-
* - [treemap](https://vega.github.io/vega/docs/transforms/treemap/)
- ❌
-
:::
## Cross-Filter Transforms
:::{list-table}
:header-rows: 1
:widths: 20 10 100
* - Transform
- Status
- Details
* - [crossfilter](https://vega.github.io/vega/docs/transforms/crossfilter/)
- ❌
-
* - [resolvefilter](https://vega.github.io/vega/docs/transforms/resolvefilter/)
- ❌
-
:::
:::{toctree}
:maxdepth: 2
:hidden: true
:caption: Vega Coverage
self
optimized_expressions
:::