Datamaps

Introduction to Datamaps

In the fields of scientific and geometric visualization, a datamap is a fundamental concept that serves as the bridge between raw numerical data and its visual representation. At its core, a datamap is a function or a lookup table that translates data values into visual properties, most commonly color. Think of it as a sophisticated legend that instructs the rendering engine how to “paint” the data onto a geometric object, such as a surface, a volume, or a set of points.

Every value in your dataset, whether it represents temperature, contaminant concentration, pressure, or a geologic material type, is assigned a color based on the rules defined in the datamap. This transformation is what turns an abstract collection of numbers into an intuitive and immediately understandable visual model. Without datamaps, a 3D model of contaminant distribution would be a colorless, featureless shape, providing no insight into where the highest concentrations are or how they vary in space. The datamap is what brings the data to life, allowing us to see the patterns, trends, and anomalies that would otherwise be hidden in spreadsheets and data files.

The Purpose of Datamaps in EVS

In Earth Volumetric Studio, datamaps are the primary tool for communicating the meaning of your data within a visual context. Their purpose extends beyond simply making things colorful; they are a critical component of data analysis and presentation for several key reasons.

First, they make complex data interpretable. A bright red area in a plume model is instantly recognizable as a “hotspot” of high concentration, while a transition from green to blue can clearly show the gradient where values are decreasing.

Second, they provide a quantitative reference. A well-designed datamap, coupled with a legend, ensures that the visualization is not just a pretty picture but a scientifically accurate representation. Each color corresponds to a specific data value or range, allowing a viewer to probe any point on a model and understand its precise quantitative meaning.

Finally, they are essential for highlighting features of interest. Data in environmental and geological sciences often spans many orders of magnitude. A datamap can be carefully designed to focus the visual contrast on the most critical parts of the data range, making subtle but important variations stand out while de-emphasizing less relevant data.

Types of Data and Datamap Processing

Datamaps in EVS are highly flexible and can be configured to handle different types of data and distributions. The way a datamap translates values to color can be linear, non-linear, or categorical.

Linear Datamaps

A linear datamap applies a smooth, uniform color gradient across the entire range of the data. The relationship between a data value and its position in the color gradient is a straight line. For example, in a dataset ranging from 0 to 1000, a value of 500 would be mapped to the exact middle of the color ramp. This type of mapping is best suited for data that is evenly distributed and where the importance of changes is consistent across the entire range, such as a simple temperature scale.

Non-Linear Datamaps

A non-linear datamap is used when the data is not uniformly distributed or when certain ranges are more important than others. In this case, the relationship between data values and colors is not a straight line. This allows you to allocate more “color space” to the most critical parts of your data range.

A classic example is contaminant concentration data, which might range from 0.01 to 10,000. If a linear datamap were used, most of the color gradient would be dedicated to the high-end values, making it impossible to distinguish between low-level concentrations (e.g., 0.1 vs. 1.0), which might be the most critical range for regulatory purposes. A non-linear datamap can be configured to stretch the color gradient across the lower values, providing high visual contrast where it is needed most.

The colors of breaks on both sides don’t have to be continuous. If the Lock Adjacent Breaks toggle in the Datamap Editor is disabled, you can choose both colors separately.

A note on precision: Due to the nature of precision in floating-point calculations, a value that is identical to a break point can be categorized into either the adjacent upper or lower interval. If you need to ensure a specific value is colored correctly, we recommend slightly shifting the break point. For example, changing a break from 500.0 to 500.0001 ensures the value 500.0 falls into the lower interval.

Categorical Data

Datamaps are also used for categorical data, which is qualitative rather than quantitative. Examples include geologic material types (“Sand”, “Clay”, “Gravel”), land-use classifications, or sample location IDs. For this type of data, the datamap assigns a single, discrete color to each unique category. There is no gradient or blending between colors. In EVS, this is typically handled by assigning an integer ID to each category (e.g., Sand=1, Clay=2). The datamap is then configured with distinct colors for each integer value, effectively creating a color key for your categorical data.

Logarithmic Processing

Logarithmic processing is a specific type of non-linear mapping designed for data that spans several orders of magnitude. By taking the logarithm of the data values before mapping them to color, vast ranges are compressed into a more manageable scale. This makes logarithmic datamaps the standard and most effective way to visualize data like hydraulic conductivity or contaminant concentrations. EVS handles this transformation automatically when the log processing option is selected in many modules, so you do not need to manually convert your data. The datamap works with the log-transformed values, but associated legends will still display the original, human-readable values.

  • Datamap Editor

    The Datamap Editor is the primary tool in Earth Volumetric Studio for creating and customizing the mapping between your data values and the colors used to represent them in a visualization. It provides a powerful, interactive interface to control color gradients, data ranges, and scaling, allowing you to effectively highlight the features of interest in your data.

Subsections of Datamaps

The Datamap Editor is the primary tool in Earth Volumetric Studio for creating and customizing the mapping between your data values and the colors used to represent them in a visualization. It provides a powerful, interactive interface to control color gradients, data ranges, and scaling, allowing you to effectively highlight the features of interest in your data.

You can access the Datamap Editor by clicking the Edit button next to the Node Data Datamap or Cell Data Datamap properties in a module’s rendering settings.

The editor is composed of three main areas: the toolbar at the top, the color ramp preview in the middle, and the color break editor at the bottom.

Toolbar

The toolbar provides access to file operations, settings, and tools for manipulating the datamap.

File and Replace Operations

OperationDescription
OpenAllows you to load a previously saved datamap configuration from a .CTDmap file, enabling you to reuse complex color schemes across different projects and models.
SaveThis dropdown menu provides two distinct ways to save the current datamap configuration to a .CTDmap file.
  • Save As Generic: Saves the datamap with its breaks defined by their relative positions (e.g., percentages). This makes the saved datamap a flexible template that will adapt to a new dataset’s minimum and maximum values.
  • Save With Values: Saves the datamap with its breaks locked to their current, fixed data values. This is useful for applying a consistent color mapping to multiple datasets that share the same data extents or have specific, meaningful thresholds.
Use TemplateApplies one of the default datamap templates, such as Default Node Map, Linear Grayscale, or perceptually uniform scientific colormaps.
Copy FromOpens a dialog to copy a datamap from another module in your application, allowing you to select a specific source and apply its datamap to the current module.
Copy ToPerforms the reverse of Copy From. It allows you to apply the current datamap’s configuration to one or more selected modules and ports.

Settings

SettingDescription
Lock Adjacent BreaksThis toggle locks the colors between breaks. When enabled, changing the color of a break point will also update the adjacent break point in the next range, ensuring a continuous color gradient.
Gradient Color RangesThis toggle controls whether to use smoothly changing colors. When enabled, colors blend seamlessly between break points. When disabled, each range is filled with a single, solid color.
Use Perceptual ColorspaceThis option switches the color interpolation method to a “visual perceptual colorspace,” which can produce gradients that are perceived as more uniform and natural by the human eye.

Operations

OperationDescription
Add BreakAdds a new break position to the datamap, allowing you to introduce a new color and data value point to refine your color gradient.
Evenly Space BreaksRedistributes all existing color breaks linearly across the full data range, creating a uniform gradient.
Clear BreaksRemoves all intermediate color breaks, leaving only the start and end points and creating a simple, two-color gradient.
Create Breaks From BandsAutomatically creates new color breaks at the exact data values used by another module (like isolines), ensuring color changes align perfectly with contour lines or other banded visualizations.
Flip RangesReverses the color ramp, so that the color previously at the maximum value is now at the minimum value, and vice-versa.
Apply Geologic MappingDesigned for categorical data, this function creates a series of discrete, solid color ranges corresponding to the integer IDs used to represent different geologic materials.

The toolbar also has similar options to the EVS Main Toolbar in terms of display style and density.

Color Ramp and Break Editor

This is the main interactive part of the editor where you define the datamap.

Color Ramp Preview: The large horizontal bar shows a preview of the final datamap. It displays the colors and the smooth transitions between them, based on the color breaks you have defined below it. The minimum and maximum data values of the current range are displayed at the ends of the ramp.

Logarithmic Scaling Indicator: Text such as “Logarithmic Scaling On” will appear to the right of the color ramp. This indicates that the datamap is currently processing the data on a logarithmic scale. This is essential for effectively visualizing data that spans several orders of magnitude, as it allocates more color variation to the lower-end values.

Color Break Editor: This section is where you define the specific points of your datamap. The datamap is composed of one or more color intervals, and the points that define the start and end of these intervals are called color breaks. Within each interval, the color transitions in a linear gradient based on the data values and colors set at its start and end breaks. A key feature of the editor is that the color at the end of one interval does not need to be continuous with the color at the start of the next. By disabling the Lock Adjacent Breaks setting, you can create a “hard break,” or an abrupt change in color at a specific data value. This is useful for visually separating distinct data ranges. Furthermore, the length of each interval can be adjusted independently, allowing you to create a non-linear datamap by stretching or compressing the color gradient across different parts of the data range.

Each color break is represented by a row in the editor, which includes:

ComponentDescription
Data Value Input BoxAllows for precise numeric entry of the data value for the break.
Color SwatchOpens a color picker to set the color for the break.
SliderProvides interactive adjustment of the data value for the break.
Delete ButtonA trash can icon to remove the break.