Exporting LIDAR Data to Other LAS Files
Sometimes it may be useful to export LIDAR points to new LAS files even though they currently exist in LAS files. Examples include exporting points you want to isolate spatially for a project or a set of points based on a filter. Another example of exporting to LAS files would be tiling LIDAR points stored in raw flight line files to facilitate the LIDAR processing workflow.
When exporting LIDAR points to the LAS file format, the points within the export area can originate in multiple LAS files and conceivably be of different file versions and/or precision. A greatest common factor rule is used when determining the file version and point precision in the new LAS file(s). For example, if some points have a precision of 2 decimals (scale of 0.01) and some other points have a precision of 3 (scale of 0.001), then the points written to the new LAS file are saved with a precision of 3.
Selecting an LAS Version
You may select an LAS version for the newly created LAS file(s). This may be useful when upgrading LAS files to new versions or rewinding the version to a previous LAS version for support in other software.
By default, a best guess LAS version is selected and is based on the existing points in the active LAS Layer. Similar to the method for choosing precision, a greatest common factor rule is used for choosing the default LAS version.
In most cases, selecting any LAS version is acceptable. However, if you want to export point records that contain fields such as color data to versions that do not support these fields, the data will stripped down when stored in the new LAS files. A warning will appear to inform you if any data may be stripped in the export process.
How to Export LIDAR Data to Other LAS Files
This is the method for completing Step 1 of the Export Wizard for output to other LAS files only.
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Open the LP360 Export Wizard by clicking the Export LIDAR Data command on the LP360 toolbar. The Export Wizard dialog will open with the Step 1 of 3 page displayed.
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Click the in the Export Type list, and select Points.
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Click the arrow in the Export Format list and select LAS from the list.
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For the LAS Version, a best choice LAS version is selected by default, but you can click the arrow on the list and select a different version.
Note Some LAS versions may not support all of the fields stored in the point records. A good example of this is color values which are only supported in the LAS 1.2 version and above. A warning may display providing some additional information and offer to cancel the selection or continue. -
Click the Source Points button to define which points you want to export. See Modifying the Point Filter for LIDAR Export for more information.
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If you are exporting to LAS format, select the LAS version you would like to export to.
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If you are exporting to LAS 1.4, you can optionally change the Point Data Record Format. Select the checkbox if you would like to do so. Then select PDRF 6, PDRF 7, or PDRF 8 from the list.
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Select one of the options to use to copy the classification bits from the source input (Input with Flags and 32 classes or Input with 256 classes).
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Use the Output Coordinate System group to set the output coordinate system. Information about the output coordinate system is displayed within the box to the left. Click the 'Select...' button to open the Select Output Coordinate System dialog, where you may change the output coordinate system. Check the appropriate checkboxes for EPSG (GeoTIFF) and WKT (Well Known Text).
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Click Next to go to the next step in the Export Wizard.
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