2a:null 2b:["$","title",null,{"children":"Housing Prices in the Bay Area by Zip Code 2021Q4 | Yeqing Huang | Observable"}] 30:T601,scatterPlots = { const hover = vl .selectSingle("hover") .on("mouseover") .encodings("x") .nearest(true) .clear("moouseout") .init({ x: "94404" }); const points = vl .layer( vl.markCircle(), vl.markPoint({ size: 40, opacity: 0.9 }).transform(vl.filter(hover)) ) .encode( vl .y() .fieldQ("medianSale") .axis({ format: "$s" }) .scale({ domain: [0, 4000000] }) .title("Median Sold Price"), vl.x().fieldN("zipBayArea").axis({ title: "Zip Code", labels: false }), vl.color().fieldN("propertyType").legend({ orient: "top" }) ); const horizontalLine = vl .markRule({ size: 1.5 }) .encode( vl.y().field("medianSale").aggregate("median"), vl.color().fieldN("propertyType") ); const verticalLine = vl .markRule({ strokeWidth: 0.5, tooltip: true }) .transform( vl.pivot("propertyType").value("medianSale").groupby(["zipBayArea"]) ) .encode( vl.x().fieldN("zipBayArea").axis({ title: "Zip Code", labels: false }), vl.opacity().value(0).if(hover, vl.value(0.7)), vl.tooltip([ vl.fieldN("zipBayArea"), "Single Family Residential", "Townhouse", "Condo/Co-op" ]) ) .select(hover); return vl .layer(points, horizontalLine, verticalLine) .data(bayAreaData.filter((d) => d.medianSale <= 4000000)) .title("2021Q4 Median Sale Price by Zip Code ") .width(width * 0.9) .height(width * 0.5) .render(); }31:[{"id":"bfcd79773059fe0aa7c5a1a5fb3614b5a5f2fe9b526c3f0303069cf103ddee9a35a25cf5fcca99b6af625233e51db8df87b64c9745e0b7e7b41708c8e22f7b8e","href":"https://static.observableusercontent.com/files/bfcd79773059fe0aa7c5a1a5fb3614b5a5f2fe9b526c3f0303069cf103ddee9a35a25cf5fcca99b6af625233e51db8df87b64c9745e0b7e7b41708c8e22f7b8e","name":"bay_area_quarterly_by_zip.csv","type":"text/csv","lastModified":1649916675719.814,"size":1512796}] 2e:{"id":"6365ee8d367b7620","slug":"bay-area-housing-prices-2021q4","title":"Housing Prices in the Bay Area by Zip Code 2021Q4","thumbnail":"0ebf5dd88f69eb6713db870686de09db20e63253b85e8c64f5b8e5db7f70cdbb","access_level":"public","create_time":"$D2022-04-13T21:54:34.976Z","update_time":"$D2022-05-04T22:25:19.812Z","view_time":null,"first_public_time":"$D2022-04-14T06:13:53.537Z","has_unpublished_edits":null,"fork":false,"stars":2,"starred":false,"owner":{"type":"team","id":"e184839af33ad5d5","login":"yeqingh","name":"Yeqing Huang","avatar_url":"https://avatars-next.observableusercontent.com/d2549798a76b80dd7045845e8dfc13016b5495ba4a7c2b721cb9888b551e3e66","tier":"starter_2024"},"version":466,"publish_version":466,"role":null,"authored":false,"authors":[{"type":"individual","id":"3fa1c3bbec147e26","login":"yeqingh","name":"Yeqing Huang","avatar_url":"https://avatars-next.observableusercontent.com/d2549798a76b80dd7045845e8dfc13016b5495ba4a7c2b721cb9888b551e3e66","tier":null}],"members":[{"type":"individual","id":"3fa1c3bbec147e26","login":"yeqingh","name":"Yeqing Huang","avatar_url":"https://avatars-next.observableusercontent.com/d2549798a76b80dd7045845e8dfc13016b5495ba4a7c2b721cb9888b551e3e66","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":true,"trashed":false,"lapsed":null,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Housing Prices in the Bay Area by Zip Code 2021Q4","cells":[{"id":0,"value":"# Housing Prices in the Bay Area by Zip Code 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":382,"value":"This notebook is part of a assignment, find more details in [this notebook](https://observablehq.com/@yeqingh/bay-area-housing-market-2021)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":5,"value":"Data Source: \n- [California zip code boundaries](https://earthworks.stanford.edu/catalog/stanford-dc841dq9031) from Stanford University\n- [Homes sold in 2021Q4](https://www.redfin.com/news/data-center/) from Redfin","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":442,"value":"## Scatterplot - An overview of the median sale price","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":279,"value":"$30","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":337,"value":"Note: Each dot represents the median price of all sold homes of a certain home type within a zip code.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":380,"value":"*Findings:* The median price of each zip code varies a lot. For some zip codes, the median sale price of condo is even higher than the median sale price of single families of some other zip codes. We can use the three horizontal lines(median of the median) as the bench mark to check if the sale price of a zip code is above 50% or below 50%.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":447,"value":"## Interactive Maps by home type","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":451,"value":"Four attributes are displayed in the maps. These attributes are obtained from Redfin. They reflect the housing market in 2021Q4. \n- Median Sale Price\n- Median Sale Price per square feet\n- Median Sale Price Year-Over-Year Change(in percentage)\n- Average Sale-to-List ratio(in percentage)\nThe last attibute is the the final sale price divided by the list price. It indicates the competitiveness of the bidding.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":21,"value":"## Single Family Residential","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":34,"value":"*You can use the magnifier on the top-right corner to search for a zip code or a city name.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":54,"value":"### Median Sale Price - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":125,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":97,"value":"### Median Sale Price per Square Feet - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":93,"value":"","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":27,"value":"### Median Sale Price Year-Over-Year Increase - 2021Q4 vs 2020Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":130,"value":"","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":63,"value":"### Average Sale-to-List Ratio - 2021Q4 ","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":58,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":136,"value":"## Townhouses","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":394,"value":"### Median Sale Price - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":141,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":399,"value":"### Median Sale Price per Square Feet - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":145,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":404,"value":"### Median Sale Price Year-Over-Year Increase - 2021Q4 vs 2020Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":150,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":409,"value":"### Average Sale-to-List Ratio - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":155,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":331,"value":"## Condos","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":414,"value":"### Median Sale Price - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":161,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":424,"value":"### Median Sale Price per Square Feet - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":166,"value":"","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":419,"value":"### Median Sale Price Year-Over-Year Increase - 2021Q4 vs 2020Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":170,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":429,"value":"### Average Sale-to-List Ratio - 2021Q4","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":176,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":456,"value":"*Conclusions:* \n1. For each indicator of each home type, we can tell that the value varies a lot among different regions.\n \n3. For the median sale price YoY change, most regions have an increase for single-family residential. Many regions have an increase in the sale price of townhouses. Surprisingly, many regions have a price drop for condos.\n \n5. For each indicator, the colors become lighter as we move on from single-family residential to townhouses and then to condos. This makes sense because single-family residential is more expensive and also more popular during the pandemic. We can tell the popularity from the average sale-to-list ratio maps(the purple ones) that the competition is more fierce for single-family residential.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":434,"value":"## Data Processing","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":438,"value":"I used a piece of [Python code](https://leetcode.com/playground/Hpyxg5SD) to combine the geographical information of each zip code with the home price information downloaded from Redfin. Then I imported the json files generated to MapBox Studio to show the interactive maps.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"","database":"$undefined"},{"id":114,"value":"bayAreaFileData = FileAttachment(\"bay_area_quarterly_by_zip.csv\").csv({\n typed: true\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":117,"value":"bayAreaData = {\n let result = [];\n\n for (const d of bayAreaFileData) {\n if (d.period_begin === \"10/1/21\") {\n result.push({\n periodBegin: d3.timeParse(\"%m/%d/%y\")(d.period_begin),\n periodEnd: d3.timeParse(\"%m/%d/%y\")(d.period_end),\n zipBayArea: d.zip_code.toString(),\n propertyType: d.property_type,\n medianSale: d.median_sale_price,\n medianSaleYoY: Math.round(d.median_sale_price_yoy * 10000) / 10000,\n medianUnitPrice: Math.round(d.median_ppsf),\n medianUnitPriceYoY: Math.round(d.median_ppsf_yoy * 10000) / 10000,\n avgSaleToList: Math.round(d.avg_sale_to_list * 10000) / 10000\n });\n }\n }\n yield result;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":120,"value":"Inputs.table(bayAreaData)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W31","stdlib":"1"}} 2f:"$2e:body"