title: The indices of the two GeoSeries are different - Understanding Indices
body: <p>I am working with <code>GeoPandas</code> and I have two <code>GeoDataframes</code> with the same <code>CRS</code>. One of them contains a <code>geometry</code> column with a polygon <code>geometry</code>, the other one a column with point <code>geometry</code>. I want to check which points are inside the polygon.</p>
  <p>Naively I tried</p>
  <pre><code>shape.contains(points)
  </code></pre>
  <p>This gave me</p>
  <pre><code>&gt;  The indices of the two GeoSeries are different
  </code></pre>
  <p>I do not understand this message. When I check the <a href="https://geopandas.org/docs/reference/api/geopandas.GeoSeries.contains.html?highlight=contains" rel="nofollow noreferrer">documentation</a>, it says</p>
  <blockquote>
  <p>We can also check two GeoSeries against each other, row by row. The GeoSeries above have different indices. We can either align both GeoSeries based on index values and compare elements with the same index using align=True or ignore index and compare elements based on their matching order using align=False:</p>
  </blockquote>
  <p>What are these Indices? Why are they checked against each other and not the <code>geometry columns</code>?
  Online I read, I have to convert my geometries into <code>shapely</code> geometries. But isn't the whole point of using <code>GeoPandas</code> that I can perfrom geographical operations on the data?</p>
  <p>I am confused about this. How to check if the <code>geometries</code> in <code>shape</code> contain any of the <code>geometries</code> in <code>points</code>?</p>