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dev:technology:supported_formats:pointcloud:opc [2021/02/15 14:54]
jeroen [Write Options] 		dev:technology:supported_formats:pointcloud:opc [2024/05/07 12:36] (current)
maarten [Remove Header]
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 ==== Strip Attributes ==== ==== Strip Attributes ====
  
-Options to remove source attributes in the target point cloud file. \\ +Options to exclude source attributes in the target point cloud file. \\ 
-Removing timestamps if available will significantly reduce the point cloud file size. +Excluding the source timestamps in the target file will significantly reduce the point cloud file size.
  
 ==== Filtering  ==== ==== Filtering  ====
  
-This spatial filtering option targets an overall homogeneous maximum point density. The filter optimizes point cloud data for web streaming and avoids point density peaks. \\+The spatial filer option targets an overall homogeneous maximum point density. Filtering is strongly recommended to optimize point cloud data for web streaming and avoids high peaks of point density. \\
 A single point cloud point per Voxel will be retained. One Block has 64x64x64 Voxels.  A single point cloud point per Voxel will be retained. One Block has 64x64x64 Voxels. 
 +
 +==== Classification ====
 +
 +Generate a dedicated OPC target file for each source point cloud class. \\
 +More information about Point Cloud Classification, see 
 +  * https://en.wikipedia.org/wiki/LAS_file_format
 +  * https://www.asprs.org/wp-content/uploads/2010/12/LAS_1_3_r11.pdf
 +  * https://www.asprs.org/wp-content/uploads/2010/12/LAS_1_4_r13.pdf
  
 ==== Block Size ==== ==== Block Size ====
  
-The Block Size is a kind of cluster size for clustering the points between different OPC levels. The best block size is found if the ratio between the number of points in one level and its adjacent level is between 2 and 3. The Block Size affects storage, performance, and also filtering if applied. \\+A Block is a spatial entity to store point cloud points within a level of the multi-resolution OPC file. The Block Size is the cubical dimension of Blocks at the lowest level of the OPC file. The Block Size unit is defined by the target Dataset CRS and metric when using Geographical CRS. The best block size is found when the ratio between the number of points in one level and the next level is between 2 to 4. \\ 
 +The Block Size affects the multi-resolution performance, the file size, and defines Voxel Filtering if set. 
  
   * Auto define density by random samples for optimized performance.   * Auto define density by random samples for optimized performance.
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     * MLS (Mobile LiDAR Scan) / Medium density / Block size 1     * MLS (Mobile LiDAR Scan) / Medium density / Block size 1
     * ALS (Airborne LiDAR Scan) / Low density / Block size 50     * ALS (Airborne LiDAR Scan) / Low density / Block size 50
-  * Custom block size. Choose a block size of your choice using the slider.+  * Custom block size ((Once the handler of a slider is selected, the left-right arrow keys can be used for precise adjustments.))
  
-==== Processing Time ====+==== Mapping Resources ==== 
 + 
 +The write options for a point cloud that is part of a mapping resource in the pointcloud/point_cloud.write.options.ini. The example configuration: 
 +  density.filter.treshold 1 
 +  block.size 1.0 
 +  write.attribute.GPSTime 0 
 +  write.attribute.color 1 
 +  write.attribute.intensity 1 
 +  intensity.8bit 1 
 +  write.attribute.classification 1 
 +Or 
 +  density.filter.treshold=1 
 +  block.size=1.0 
 +  write.attribute.GPSTime=false 
 +  write.attribute.color=true 
 +  write.attribute.intensity=true 
 +  intensity.8bit=true 
 +  write.attribute.Classification=true 
 + 
 +For this configuration: the point cloud filtering is enabled, block size is set to 1, the timestamp attribute is stripped, the color, intensity and classification attribute are written and the intensity values are clipped to an 8-bit range. 
 + 
 + 
 + 
 +===== Processing Time =====
  
 Importing a point cloud resource file to OPC is a one time process. \\ Importing a point cloud resource file to OPC is a one time process. \\
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 For example, reading a LAS file from SSD to write an OPC to SSD storage using Intel i7 processor and 4GB Memory will take 2 Seconds per Million points.  For example, reading a LAS file from SSD to write an OPC to SSD storage using Intel i7 processor and 4GB Memory will take 2 Seconds per Million points. 
  
-==== Legend and Georeference ====+===== Remove Header ===== 
 +The CRS header can be removed from the Resource via the Dataset Properties Window. Unique upload situations may require OPC data to not have the CRS header.  Some situations include: 
 +  * Geospatial Alignments in iModels 
 +    * iModels with custom CRS   
 +    * Local Scan Data 
 +    * Scan data referenced and tied to custom iModel CRS 
 +    * No available CRS to assign local data 
 + 
 +Clearing the Point Cloud header enables the OPC data to be placed within the local/custom CRS grid from these iModel(s). Take note, extra care, knowledge, and information is required for these geospatial alignments.   
 + 
 +If the iModels requires this, the import Mapping Template can have the pointcloud.write.options.ini updated with: 
 +   
 +   remove.crs.header true  
 + 
 +===== Legend and Georeference =====
  
 The resource can be accompanied by an [[dev:technology:supported_formats:other:olg|]] and [[dev:technology:supported_formats:other:ord|]]. The resource can be accompanied by an [[dev:technology:supported_formats:other:olg|]] and [[dev:technology:supported_formats:other:ord|]].
 
Last modified:: 2021/02/15 14:54