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Raw Data Layers

A Raw layer is a traditional GIS data layer - a set of geo-referenced geometry without any higher-level knowledge of the what the geometry represents.  This is useful for types of abstract data which do not have a real existence in the world, such as administrative borders, general reference points, and so on.

The layers are called "Raw" because in the VTP philosphy, they are temporary raw data, before being converted or "cooked" into more meaningful information.  For example, 2D point data which represents the location of trees, is cooked from points (a Raw layer) into actual trees (a Vegetation layer).

Menu: Raw

• Select Features
  • Use this mode to select features with the mouse
• Pick Features
  • This mode is useful for clicking on individual features to get information about them.
• Show Attribute Table
  • Shows the Feature Info dialog, which displays attributes in a table
• Set Entity Type
  • Set the kind of entity (Point, Arc, Polygon) that this layer contains.  You can only change this when the layer is empty.
• Add Points with Mouse
  • In this mode, you can click the mouse in the main view to add points.
• Add Point with Text
  • Lets you type in the precise coordinate of a point to add.
• Add Points with GPS
  • (not implemented yet)
• Add Feature from WKT
  • If you are GIS geek, you may want to add a feature with a Well-known text string.
• Style..
  • (not implemented yet)
• Scale Horizontally
  • Asks for a scale factor, then mulitplies all the ground (X, Y) coordinates of all the features in the layer.
• Scale Vertically
  • For 3D feature types, asks for a scale factor, then mulitplies the vertical (Z) coordinates of all the features in the layer.
• Offset Vertically
  • For 3D feature types, asks for a vertical distance, then adds that to all (Z) coordinates of all the features in the layer.
• Clean Polygon Geometry
  • For polygon (or polyline) features types, the following is done:
    1. Remove degenerate points (two points in sequence, too close to each other)
    2. Remove colinear points (two points in sequence, almost exactly on the same line)
    3. For polygons, fixes the winding (clockwise-ness).
    4. For polygons, removes any polygons that have rings with less than 3 vertices.
    5. For polylines, removes any polylines with less than 2 vertices.
• Select Bad Geometry
  • Some polygons have degeneracies which are difficult to fix automatically.  In particular, a polygon's edges may cross each other, or a point of an inner ring (hole) may coincide or be numerically too close to a point in the outer ring.  Since they can't be automatically fixed, this command will select them for you, so you can find them to fix them manually. 
• Select Features by Condition
  • Allows you to use simple logical expressions to select features.
• Export as HTML Imagemap
  • A somewhat specialized command, it will take a snapshot of your view, save it to a PNG file, then write an HTML file with the <map> and <img> tags for making a pickable webpage from the current polygon layer.
• Export as KML
  • Write the layer to a Google Earth-style KML file.
• Generate Grid from 3D Points
  • Interpolates a set of points, using the algorithm from the QuikGrid software, to produce a continuous surface as a new elevation layer.
• Generate TIN
  • Triangulates a set of points to produce a TIN as a new elevation layer.
• Generate Polygons from Polylines
  • Given a layer of polylines, it will look for polylines which are closed (first and last point are in the same place) and create a new layer containing those as polygons.