- local metrical mapping in the scrolling local perceptual map;
- global topological mapping given the local metrical maps, generating a tree of all possible maps to resolve structural ambiguities;
- a global metrical map, given the local metrical and global topological maps.

- This IJRR paper brings all the pieces together, and shows how the
mapping problem can be factored, and the pieces can be used together.
Patrick Beeson, Joseph Modayil, Benjamin Kuipers. 2010.

**Factoring the mapping problem: Mobile robot map-building in the Hybrid Spatial Semantic Hierarchy**

International Journal of Robotics Research**29**(4): 428-459, 2010. - This ICRA-05 paper describes how places are detected during
continuous motion through a continuous environment. It provides an
extension to the Voronoi Graph that overcomes a number of problems.
Patrick Beeson, Nicholas K. Jong, and Benjamin Kuipers. 2005.

**Towards Autonomous Topological Place Detection Using the Extended Voronoi Graph**.

IEEE International Conference on Robotics and Automaton (ICRA-05). - This ICRA-04 paper describes the scrolling local perceptual map,
the abstraction from place neighborhoods in small-scale space to
local topological descriptions in large-scale space, and the
map-tree algorithm for generating possible topological maps and
filtering them for consistency.
Benjamin Kuipers, Joseph Modayil, Patrick Beeson, Matt MacMahon, and Francesco Savelli. 2004.

**Local metrical and global topological maps in the hybrid Spatial Semantic Hierarchy**.

IEEE International Conference on Robotics and Automation (ICRA-04). - This IROS-04 paper shows how we can build a highly accurate
global metrical map, by using the structure of the topological map
as a skeleton.
Joseph Modayil, Patrick Beeson and Benjamin Kuipers. 2004.

**Using the topological skeleton for scalable global metrical map-building**.

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS-04). - This IROS-04 papers describes a consistency test for proposed
topological maps based on planarity. This test prunes the tree of
possible maps dramatically.
Francesco Savelli and Benjamin Kuipers. 2004.

**Loop-closing and planarity in topological map-building**.

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS-04). - This AIJ paper, describing Emilio's PhD thesis, gives an
axiomatization in non-monotonic logic for the topological map.
Potential maps are pruned from the tree of maps if they violate
any of these axioms.
Emilio Remolina and Benjamin Kuipers. 2004.

**Towards a general theory of topological maps**.

*Artificial Intelligence***152**: 47-104, 2004. - This AIJ paper gives an overview of the Spatial Semantic
Hierarchy, which decomposes knowledge of large-scale space into
several different representations, each with its own distinctive
ontology for space.
Benjamin Kuipers. 2000.

**The Spatial Semantic Hierarchy**.

Artificial Intelligence Journal**119**: 191-233.

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