Terrain Height Map

Verifies the image against terrain height map characteristics.

Parameter table

No parameter available.

Detailed description

This rule checks if the provided image can be classified as a terrain height map. A terrain height map is a grayscale image representing elevation data with varying intensities of pixels.

To assess whether an image is a terrain height map, we analyze the gradient magnitudes across the image. A true terrain height map should have smooth transitions in elevation, which reflect in low gradient magnitudes.

The specific criteria used to evaluate an image are:

• The gradient magnitude of each pixel, calculated as the squared norm, should predominantly fall below the threshold of 0.03 (on a normalized scale of 0 to 1, relative to the maximum pixel intensity value).
• A small percentage of gradients can exceed this threshold, but if more than 10% do, the image likely does not represent a realistic terrain height map.

Through this analysis, we can determine the likelihood of the image being a terrain height map. An image meeting these criteria is likely to be a good representation of terrain elevation.

Creator tips

• When creating a terrain height map, ensure that the grayscale values accurately represent the elevation levels.

• Use a smooth gradient that allows to represent the gradual change in topography. Sharp transitions in grayscale values might not represent a realistic height map.

• To create more detailed and accurate terrain height maps, consider using specialized software like . AwesomeBump is an open-source program that can convert images to height maps and normal maps, among other features. It can help in refining the texture to better suit the requirements of a height map.

Pay attention to the gradient magnitudes across your height map and adjust the texture accordingly to avoid sharp elevation changes unless they are a specific feature of your terrain.

Remember to test your height map in the context of your 3D application to ensure it behaves as expected when applied to a surface.

Examples

value	valid	description
	✅	The image should represent a smooth transition in elevation, typical of a terrain height map.
	❌	The image should not feature abrupt elevation changes, uncharacteristic of a terrain height map.