 <p>The <code>within_polygon</code> function is only available on the newest API endpoint for each dataset, so make sure you're using the correct endpoint. You should be using this one instead: </p> <p><a href="https://dev.socrata.com/foundry/#/data.seattle.gov/3c4b-gdxv" rel="nofollow">https://dev.socrata.com/foundry/#/data.seattle.gov/3c4b-gdxv</a></p> <p>Using that endpoint, and correcting the location fieldname to <code>location</code>, I was able to create this query that works:</p> <pre><code>https://data.seattle.gov/resource/3c4b-gdxv.json?$where=within_polygon(location,%20%27MULTIPOLYGON(((-122.345239999941%2047.7339842230969,-122.344670705637%2047.7051200031236,%20-122.35540073991%2047.7051536806063,-122.355548433321%2047.7340195160745,%20-122.345239999941%2047.7339842230969)))%27) </code></pre>