> For the complete documentation index, see [llms.txt](https://help.felt.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.felt.com/analysis-and-dashboards/spatial-analysis.md).
# Spatial analysis
Join, buffer, dissolve, clip, and intersect layers, and create travel-time areas, with the Analysis tool.
| Task | Plans |
| ------------------------------------------------- | ------------------------------ |
| Run an analysis, combine layers, and clip a layer | Team, Business, and Enterprise |
| Create travel-time areas | Business and Enterprise |
| Crop a raster layer | Business and Enterprise |
| Sample raster | Business and Enterprise |
[Compare plans](https://felt.com/pricing#compare)
Spatial analysis creates a new layer from one or two map layers, leaving the inputs unchanged. The **Analysis** tool runs operations such as join, buffer, clip, and travel time.
For an operation the **Analysis** tool doesn't have, such as finding the nearest feature or summing point values in each polygon, ask Felt AI. See [Query map layers with SQL](/felt-ai/ai-assistant.md#query-map-layers-with-sql).
## Create travel-time areas
A travel-time area, or isochrone, shows how far you can travel by car, bike, or on foot in up to 120 minutes. The **Travel time** operation creates a layer with one area for each point and travel time.
1. Click **Analysis**  in the toolbar and select **Travel time**.
2. In **Measure travel time from**, select a point layer.
3. In **Mode**, select **Drive**, **Walk**, or **Bike**.
4. In **Travel time**, enter the minutes. To add another time, such as 10, 20, and 30 minutes, click **Add travel time**. You can add up to five.
5. Click **Apply**. The result appears in the legend as a new layer.
One run can create up to 10,000 areas, counting each point once for each travel time. For more, filter the layer, use fewer travel times, or select **Features on screen** in **Apply to**. To check one place, use the **Travel time** type in [Measure](/tools/measure.md#measure-travel-time). You can also ask Felt AI, such as "Show the area within a 15-minute walk of each school". For straight-line distance, use **Buffer**.
## Run an analysis
1. Click **Analysis**  in the toolbar.
2. Select an operation, such as **Buffer**. The **Analysis** panel opens.
3. Select the input layer. For an operation that compares two layers, select the second layer too.
4. In **Settings**, set the operation's options.
5. Optional: In **Apply to**, select **Features on screen** to analyze only the current map view. For layers larger than 500 MB, this is the default.
6. Click **Apply**. The result appears in the legend as a new layer.
Analysis uses only features that pass a layer's filters. See [Filter layers](/layers/filter-layers.md).
Analysis results are created once and don't update when an input layer refreshes. For results that stay current, [connect a data source](/upload-anything/data-sources/add-a-source.md), define a [SQL query](/upload-anything/sql-queries.md), and turn on [live refresh](/upload-anything/refresh-data.md#set-up-a-live-layer). Results count toward processing. See [Plan usage](/plans-and-billing/plan-usage.md).
## Combine layers
Use **Join** to combine attributes or **Dissolve** to merge polygons. To stack features from two layers into one, ask Felt AI; the **Analysis** tool can't append layers.
### Join
**Join** adds one layer's attributes to another by matching values in each layer's join key column. For example, both layers might have a tract ID column. **Join** matches values, not locations; to combine by location, use **Intersect** or **Count points**.
1. In the toolbar, click **Analysis** > **Join**.
2. Under **Join data and geometry from…**, select the layer whose shapes you want in the result and its **Join key** column.
3. Under **… with data from**, select the second layer and its **Join key** column. This layer can be a table with no geometry.
4. Optional: Under **… and keep unmatched rows from**, clear a layer to drop its unmatched rows. Both layers are selected by default, so every row is kept.
5. Click **Apply**.
Join key values must match exactly, so check spelling and format first. To attach a spreadsheet to places such as counties or ZIP codes, see [Spreadsheets and geocoding](/upload-anything/files/spreadsheets-and-geocoding.md).
### Dissolve
**Dissolve** merges polygons in one layer and removes the boundaries between them. For example, it can merge a property's parcels. In **Combine**, select **All features** (the default) to make one polygon, or **Overlapping features** to make one polygon per group of overlapping or touching features.
**Dissolve** doesn't group by an attribute, so first filter the layer to the polygons you want. To dissolve polygons from two layers, first combine the layers with Felt AI.
## Clip a layer to a boundary
**Clip** trims a point, line, or polygon layer to the polygons of a second layer and keeps the input layer's attributes. For example, clip roads to a county boundary.
1. In the toolbar, click **Analysis** > **Clip**.
2. Under **Cut out data from…**, select the layer to trim.
3. Under **… where it overlaps with**, select the boundary layer. It must be a polygon layer.
4. Click **Apply**.
To clip a layer to an annotation, such as a polygon you drew, select the annotation, right-click, click **Actions** > **Convert to layer**, and use that layer as the boundary. The basemap can't be clipped; to mask land or water, use a land or water polygon layer.
### Crop a raster layer
**Clip** doesn't support raster layers. To crop a raster, add the Spatial filter extension from **Developer Platform** in the toolbar. Draw a shape in view mode, then export the raster from the filter panel as a GeoTIFF clipped to that shape. On the map, the filter hides pixels outside the shape only for you. See [Spatial filter](/tools/spatial-filter.md).
**Sample raster** writes raster values into a vector layer; it doesn't produce a raster.
## Sample raster
**Sample raster** adds raster values to a point, line, or polygon layer as new attributes. For example, it can calculate each parcel's average elevation, a type of zonal statistic.
1. In the toolbar, click **Analysis** > **Sample raster**.
2. Under **Calculate statistics for each feature of…**, select the vector layer.
3. In **Raster layer**, select the raster.
4. In **Bands**, select the bands to read.
5. Select the statistics, such as **Average**, or **Most common** for categories such as land cover.
6. Click **Apply**.
## Analysis operations
| Operation | What it does | Example use | Input | Second layer | Output |
| ------------- | ----------------------------------------------------------------------------------------------------------- | ----------------------------------------------------- | -------------------------- | ------------------ | ---------------------- |
| Buffer | Draws a polygon covering everything within a set distance of each feature, in ft, mi, m, or km | Find places within half a mile of a hospital | Points, lines, or polygons | None | Polygons |
| Bounds | Draws the smallest rectangle around each feature | Simplify detailed shapes to broad coverage areas | Lines or polygons | None | Polygons |
| Centroid | Places a point at the center of each feature, keeping its attributes | Turn metro area polygons into points | Lines or polygons | None | Points |
| Dissolve | Merges all polygons into one, or merges groups of overlapping or touching polygons | Merge overlapping buffers into one area | Polygons | None | Polygons |
| Clip | Keeps the parts of each feature inside the second layer's polygons, preserving the input layer's attributes | Cut a countrywide layer down to your area of interest | Points, lines, or polygons | Polygons | Same as input |
| Intersect | Creates one feature per overlap, with attributes from both layers | Find the roads inside national parks | Points, lines, or polygons | Polygons | Same as input |
| Subtract | Removes the parts of each feature inside the second layer's polygons | Remove flood zones from candidate development sites | Points, lines, or polygons | Polygons | Same as input |
| Count points | Adds the number of points inside each polygon | Count the airports in each US state | Polygons | Points | Polygons |
| Join | Adds a second layer's attributes by matching values in a column from each layer | Add GDP figures from a table to a countries layer | Any layer or table | Any layer or table | First layer's geometry |
| Sample raster | Adds raster values or statistics to each feature | Find the average elevation of each parcel | Points, lines, or polygons | A raster layer | Same as input |
| Travel time | Draws the area you can reach from each point in a set time by car, bike, or on foot | Find the area within a 15-minute walk of each school | Points | None | Polygons |
## Try the spatial analysis exercise
The spatial analysis exercise finds habitat for the Iberian lynx. [Download the datasets](https://drive.google.com/drive/folders/1eKmVEg1hZk8TlVnQPu150oaTQNu07YkX), then follow the video.
{% embed url="" %}
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