crosswalk_functions.Rmd

---
title: "Crosswalk Functions"
author: "Aseem Deodhar"
date: "2/3/2022"
output:
  md_document:
    variant: markdown_github

---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## Crosswalk Functions

These two functions are used to call the two respective kinds of crosswalks available in this package - weighted, and nested crosswalks.

### Weighted Crosswalks

```mapcdatakeys::crosswalk_wtd(geography, vintage)```

This is a function to call desired weighted crosswalk for population and housing unit values in desired census geographies and vintage.

It requires two arguments:

* **geography:** It can either be 'block', 'block group', 'tract', or 'county subdivision'

* **vintage:** Currently available for either 2010 or 2020 census geographies. For municipalities, either vintage will provide the same data.

##### Example: 2020 and 2010 values for housing units and population for 2010 Census Tract geographies (ct10_id)
```{r}
head(mapcdatakeys::crosswalk_wtd(geography = 'tract', vintage = 2010))
```

##### Example: 2020 and 2010 values for housing units and population for 2020 Census Block Group geographies (bg20_id)
```{r}
head(mapcdatakeys::crosswalk_wtd(geography = 'block group', vintage = 2020))
```

### Geographic Crosswalks

```mapcdatakeys::crosswalk_wtd(geography, vintage)```

This is a function to call desired nested crosswalk for census geographies and vintage.

It requires one argument:

* **year:** Currently available for either 2010 or 2020 census geographies.

##### Example: 2020 block assignment files and nested geographies for block, block group, tract, municipality, county, and state for Massachusetts.
```{r}
head(mapcdatakeys::crosswalk_geog(year = 2020))
```