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@@ -58,10 +58,10 @@ components in a single vector map are related. For example in a
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non-topological GIS if two areas shared a common border that border
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would be digitized two times and also stored in duplicate. In a
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topological GIS this border exists once and is shared between two
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-areas. Topological represenation of vector data helps to produce and
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+areas. Topological representation of vector data helps to produce and
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maintain vector maps with clean geometry as well as enables certain
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analyses that can not be conducted with non-topological or spaghetti
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-data. In GRASS topological data are refered to as level 2 data and
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+data. In GRASS, topological data are refered to as level 2 data and
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spaghetti data is referred to as level 1.
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<p>
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Sometimes topology is not necessary and the additional memory and
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@@ -81,18 +81,18 @@ approximation and topographic analysis from a point or isoline file.
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<li> line: a directed sequence of connected vertices with two endpoints called nodes; </li>
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<li> boundary: the border line to describe an area; </li>
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<li> centroid: a point within a closed ring of boundaries; </li>
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-<li> area: the topological composition of a closed ring of boundaries and optionally a centroid; </li>
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+<li> area: the topological composition of a closed ring of boundaries and a centroid; </li>
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<li> face: a 3D area; </li>
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<li> kernel: a 3D centroid in a volume (not yet implemented); </li>
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<li> volume: a 3D corpus, the topological composition of faces and kernel (not yet implemented). </li>
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</ul>
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<p>
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-Note that all lines and boundaries can be polylines (with vertices in between).
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+Lines and boundaries can be composed of multiple vertices.
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<p>
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Area topology also holds information about isles. These isles are located
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within that area, not touching the boundaries of the outer area. Isles
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-consist of one or more areas and are used internally to maintain correct
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-topology for areas.
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+are holes inside the area, can consist of one or more areas and are used
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+internally to maintain correct topology for areas.
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<p>
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The <a href="v.type.html">v.type</a> module can be used to convert
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@@ -111,14 +111,14 @@ Adjacent polygons can be found by <a href="v.to.db.html">v.to.db</a>
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<p>
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Many operations including extraction, queries, overlay, and export will
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only act on features which have been assigned a category number. Typically
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-a centroid will hold the attribute data for the area between it and its
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-boundaries. Boundaries are not typically given a category ID as it would be
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+a centroid will hold the attribute data for the area with which the centroid is
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+associated. Boundaries are not typically given a category ID as it would be
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ambiguous as to which area either side of it the attribute data would belong
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to. An exception might be when the boundary between two crop-fields is the
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center-line of a road, and the category information is an index to the road
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name. For everyday use boundaries and centroids can be treated as internal
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-data types and the user can work directly and more simply with the "area"
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-meta-feature type.
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+data types and the user can work directly and more simply with the "area"
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+type.
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<h3>Vector object categories and attribute management</h3>
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@@ -224,7 +224,7 @@ To bulk process attributes, it is recommended to use SQL
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<h3>Geometry operations</h3>
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The module <a href="v.in.region.html">v.in.region</a> saves the
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-current region boundary into a vector area.
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+current region extents as a vector area.
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Split vector lines can be changes to polylines by
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<a href="v.build.polylines.html">v.build.polylines</a>. Long lines can be
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