I would like to embed the chart from a Google Docs spreadsheet into a Google Docs Document, so changes to the original will be reflected in the embedded version. I found a way to embed a static image of the chart, but I can't get it to update.
Note that I only want to embed the chart itself (which could be a pie chart, organigram… etc.), no other parts of the spreadsheet — including its cells and data — should be included.
To insert the chart as an image, publish the chart from the Google Spreadsheets using the little arrow dropdown menu when selected. In the type dropdown, select "image" instead of "interactive". (In the resulting URL, this changes the format parameter's value.) Use the URL to insert it as an image "by URL" in your Google Docs Document.
The image referenced by the URL actually updates according to the spreadsheet, but unfortunately Google Docs (currently) seems to cache images inserted into a document by URL.
Best Answer
This is now a built-in feature in Google Docs: see Add a chart to a document.
The linked charts are not updated automatically: instead, a floating button "Update" appears in upper right corner of a linked chart when changes to the linked spreadsheet are detected. Click this button to update the chart.