Definitions:

• Marker - symbol for drawing point features or points on the graphic layer. Point markers can be created from:
  • Images - click button Add Image to select an image file. The image must be no larger than 128 x 128 pixels. It is recommended that you use images in format PNG with defined transparency to achieve best effect.
  • Symbols - you can add symbols from installed fonts on your computer. ET Terrain Viewer provides a font named ETTV2, which contains a number of symbols. Click button Add Symbol, then select the desired font, select the color for the symbol, and type in the desired symbol, or select one from the drop-down list. ET Terrain Viewer will convert the symbol into a transparent image, and add it to the library.
• Texture - an image to be used for rendering features representing area (polygons, extrusion walls) features or surfaces. Supported image formats are BMP, JPEG and PNG. The maximum size of textures is 512 x 512 pixels. The texture images can be tiled to fill the polygons, so in order to avoid getting ”waffle” effect you need to use so called seamless images. Some seamless textures are provided with the installation of the software.
  Note: Using large and many textures or using finest tiling can have a negative impact on performance.
• Color Ramp - array of colors used to render continuous data. ET Terrain Viewer provides several pre-defined color ramps. The user can create new color ramps on the Options panel (Tools - Options - Ramps - Add) by providing two or more colors to be used in the ramp.

Classification:

• Single Value - A single symbol is used to render the entire surface or all features of the feature class.
• Range - You specify the number of classes required. Initially, the software calculates the class breaks using the minimum and maximum values and the number of classes requested, creating equal intervals. You can later to adjust the boundaries of the each interval. Adjacent intervals will be adjusted automatically to avoid fragmentation. You can change the class symbol (color, texture or point marker) and class breaks by double clicking on a specific class and change the values in the class properties dialog.
  If the selected symbol is “Color” the current color ramp is used to populate the symbols for the different classes. If the selected color ramp contains less colors than the number of classes, ET Terrain Viewer will generate the necessary gradient colors to match the number of classes.
  If “Texture” or “Point Marker” is selected the user needs to select texture image / point marker for each class.
• Unique Values – If the attribute table of the feature class has a string or integer field that defines different categories of features, unique value classification can be used. The user needs to select an integer or string field that has no more than 50 unique values.

ET Terrain Viewer can display three major layer types:

• Surfaces (Rasters or TINs) can be rendered only based on elevation. You can use for rendering a color ramp or texture images.
• Features can be rendered based on their elevation or the values in the selected attribute field. Depending on the geometry type the following symbol options are available:
  • Point – By default, when a new point layer is added to a project, the first marker from the list of predefined markers is assigned to the layer. You can select a marker for the layer from the already existing ones, or add a new one.
  • Polyline – Only color can be used.
  • Polygon – Colors and textures can be used.
  • Multipatch - Colors and textures can be used.
  • Polygon and Polygon Extrusion (the walls created if the features are extruded) - Colors and textures can be used.
  • Extruded Point (the lines created) - Only color can be used.
• Georeferenced images (e.g. aerial photos) – the actual image colors. No symbology is available.