minor edits
minor edits

spatial-ucsb/ConceptsOfSpatialInformation,spatial-ucsb/ConceptsOfSpatialInformation,liangcun/ConceptsOfSpatialInformation,spatial-ucsb/ConceptsOfSpatialInformation,liangcun/ConceptsOfSpatialInformation,liangcun/ConceptsOfSpatialInformation