Geography Reference
In-Depth Information
Hardware requirements correspond to the big data needs. AMD Opteron and
Intel i7 2600K CPU, with minimum of 16 GB memory, fast SATA III SSD
(500 MB/s) and GeForce 460 GTX. Some parallelizable tasks can be distributed
across the distributed architecture, e.g. Apache
®
Hadoop
®
.
Mainly a 64 bit software is used to fully utilize RAM capacity. Fully sufficient
for the GIS operations is the ArcGIS 10 SP3 or a free version of the SagaGIS.
Advantage of the ArcGIS is that it allows implementing Python made additions
directly in the map environment. Graphical tasks are completed in the Autodesk 3D
Studio Max 2012, which allows object oriented scripting and processing of wide
range of data inputs. Any similar application can be chosen upon the needs of the set
analysis.
Methods and Procedures
This chapter characterizes details of the individual steps needed to reach the given
set of the aims. The proposed procedure consists of the following steps:
• Creation of the 3D polygonal digital terrain model from LIDAR data
• LIDAR data filtering and trees recognition, the following layers are created:
- Top cover layer (ground and tops of the trees)
- Treetops layer
- Inner vegetation layer
• Raster transformations: creation of black-white rasters from filtered LIDAR
data to describe location and height of trees in terrain
- Raster describing real heights of trees (in the given length unit)
- Recalculated raster of normalized trees heights
- Raster describing positions of each tree
• Raster driven digital cloud model: creation of black-white rasters from NOAA
images to describe location and size of clouds
• Creation of output 3D photorealistic model of surface
Creation of the 3D Terrain Model
A 3D terrain model (the ground for the vegetation and other surface objects) and its
creation is based on the LIDAR scanned values. Raw LIDAR data are transferred
into the quadrilateral polygonal form. This form is easy to edit, subdivide and has a
nice, clean and predictable edge flow.
Laser scan is carefully checked and corrected—registered, merged, de-noised
etc. It is simplified by chosen interpolation technique into the form of quadrilateral
