The RAW picture of the terrain

We have seen on the last post that VT Builder could be a quicker solution than QGIS and effectively, the result is very good, but when working on a very large terrain, the tiles imported in VTBuilder are not continuous and the result imported in Unity is not so good. So lastly, I have decided to create the terrain only using QGIS.

With VTBuilder, I could export all the information that I was missing with QGIS. VTBuilder could tell the value of one unit on the elevation and minimum and maximum elevation of each tile. The results were as fellow:

N36W115 - min: 145.39 - max: 2177.43
N36W116 - min: 295.49 - max: 2592.45
N36W117 - min: -78.43 - max: 1875.10
N37W115 - min: 201.96 - max: 2467.01
N37W116 - min: 479.90 - max: 3631.91
N37W117 - min: -85.62 - max: 2178.92

In QGIS, I have created one layer style with the minimum and maximum values that I have copied to all layers. I have rendered each tile, created a new project and I merged all the rendered tiles into one layer that I have exported. The result was a high quality TIFF picture of 32,412 x 21,612 px, 2.60GB.

I have tried to reduce the picture to 2048x2048 px but the result in Unity is really not good. We are loosing the quality of the relief and the camera does not render properly. As a solution often used with Unity, I will cut the HD image into smaller pictures and tile the terrain with Unity.

In QGIS, we see that USGS tiles are rectangles while they are rendered square with VTBuilder. One tile is one degree longitude and one degree latitude. The length of the degree between two meridian will change accordingly to the position with the equator. We can have an estimate of the degree accordingly to its latitude on this website. Las Vegas is situated around 37.25 latitude which gave the width of 110,982.31 meters while the distance between two degrees latitude still be 111.32 km. The image rendered with QGIS is 32,412 x 21,612 px what means that QGIS has valued one degree to 10806 px. I will work with this value to scale the design of the maps.

The very best reason I use QGIS is to export maps accordingly to GPS coordinates so I can create layers of maps and assemble them into Unity. Unity is working with squares, so the length of the terrain will be scaled accordingly to the rendering of QGIS with 1px = 100m. Each tile into Unity will be shaped 2048 x 2048 px, the heightmaps will be 2049 px. I will be able to re-scale the terrain when rendering the street view. As we see on the pictures below, it still be a long work to do before we can design the final terrain.

One thing to keep in mind is the rendering of the street view map scaled 1:5000. The final scale of the terrain must be designed accordingly to this quality of rendering.

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