Visualizing Grids

Owned by Erlend Kvinnesland
Last updated: Mar 06, 2014 by Olav Egeland (Unlicensed)
3 min read

Introduction

There are several ways to display grids and their properties in Geocap, depending on the grid type (terrain, horizon etc), the resolution of the grid and the purpose of the visualization. The three main elements which enhances the way you perceive a grids shape and relief are the; Z-scale, colors and contours. As previously explained in the interface chapter, the z-scale is changed by simply scrolling the mouse wheel. The rest of this page explains how to enable the use of colors and contours to achieve best possible visualization for grids.

Grid resolution and display

Working interactively it is desirable to visualize fast and accurate. For very large grids a standard (not LOD) rendering of every grid cell would take quite a while. The default procedure is to use decimation when displaying a large grid. The actual decimation is listed in the lower toolbar to the left. The user can turn decimation on/off if necessary. Decimation will get less when in 2D mode and zooming in on a detail. For more details please read the article: Notes on grid visualization.



In this section:

Display grid

The Display command displays the grid in one solid color. By executing this command several times on the same dataset the display color will change randomly. You can also set a specific color by right clicking the command in the Toolbox and select edit. Check the User Defined Color box and select a color in the palette.

Map grid

When mapping a grid each grid cell will get a color based on its value. The color is based on the color table range and properties of the dataset. Geocap lets you customize the way you map a grid anyway you would like. Read more about how to do this: Color Tables

Depending on the grids schema, Geocap offers several default commands for mapping a grid.

Map Data
This command is available for all grids. It uses your active color table (usually red to blue) and the data range for color mapping.

Map Land
This is a specialized command for mapping terrain above sea level which is available for datasets with the seabed surface schema. The color table range is from gray to dark green, and it will only map grid cells with values above sea level.

Map Sea
This is a specialized command for mapping terrain below sea level which is available for datasets with the seabed surface schema. The color table range is from light blue to dark blue, and it will only map grid cells with values below sea level.

LOD (Level Of Detail)

As explained at the start of the visualization chapter, Geocap uses decimation to reduce the resolution of the displayed dataset so that the visualization is quicker. You can avoid this decimation by using the LOD Grid Display command.

LOD decimates on-the-fly and the decimation is based on the current zoom level. This means that the resolution increases automatically when you zoom closer. This can be illustrated by displaying the grid in LOD, move in to wire mode by clicking w on the keyboard and then zoom in and out. 

The LOD Grid Display can display the grid in a solid color like the Display command or from a color table like the Map Data command.

Display color bands and line contours

The Display Contours command lets you create contour of your grid. The command offers a vast amount of settings that lets you customize the contours anyway you would like. Click the icon at the top of the command menu in Geocap to read more about how to use this command.