There are quite a few settings to think about when converting to POD format. They are not all obviously useful, but each is there for a reason. Each point cloud format is designed to serve the need of it’s creator, and often the hardware with which it is created. Therefore, not all point clouds are created equal, and they may contain a lot of extra information over the mandatory X Y and Z. The challenge for the POD format is to make sense of the many types of point cloud available.
I will talk about some of the settings you will come across when converting a point cloud file to POD:
CompressionPOD files compress cloud data for efficient storage and faster retrieval from disk. You can set the accuracy you wish to maintain. It is important to consider the accuracy of the instrument used to acquire the data and to not set the compression accuracy too high. If the required accuracy cannot be achieved the data will not be compressed.
e.g. if you are using data captured from the air by aeroplane, helicopter, UAV, etc the absolute accuracy of each point will not be better than +/-10cm, so setting the Compression to 1mm is unnecessary, this will make a POD that is larger than it needs to be.
e.g. if you have a terrestrial scan with accuracy of +/-10mm and you set compression to 1m you will lose some of your accuracy.
Uniform spatial filterThis option will filter the data on import to the specified point spacing. This may increase import times considerably
e.g. (assuming the project is in meters) if you set the Uniform Filter to 1 the POD file will contain point that are no closer than 1m to the next point in any direction.
This can be very useful if you have lots of overlapping scans and you wish to filter out unnecessary points to create a smaller POD
These options can also be set at the point of export, I will often convert the entire project without any filters and view it in Pointools to see what it looks like, then decide if anything needs to be done to it, if I want to apply a Uniform Filter at this point I simply export from Pointools run the POD back through PODcreator.