developers, I'm having a weird problem with las2txt and i think las2las as well. I am trying to subset this file (http://169.229.13.22/pub/LiDAR/ucd_04.las) using the commands:
las2txt --delimiter " " --parse xyzRGBc -i ucd_04.las -o ~/Desktop/04_0.txt -v -e "412725.875 4532149.5 412860.34375 4532359.5" --first-return-only --keep-classes 1 which returns Opening ucd_04.las to fetch Header Keeping classes with the values: 1 --------------------------------------------------------- Clipping file to the extent --------------------------------------------------------- minx: 412725.875000 miny: 4532149.500000 minz: 0.000000 maxx: 412860.343750 maxy: 4532359.500000 maxz: 0.000000 --------------------------------------------------------- Keeping first returns only. Setting precisions from header to 2 2 2 8 Using delimiter ' ' Writing points: - : 0.error: detail::liblas::read_n<T> input stream is not readable if i remove the '--first-return-only' argument the command succeeds las2las using the same coordinates succeeds with both arguments however when using the 'first-returns-only' argument the resulting .las file has no points. las2las just clipping the file to the coordinates shows that there are first returns within that region: las2las -i ucd_04.las -o ~/Desktop/04_0.las -v -e "412725.875 4532149.5 412860.34375 4532359.5" Opening ucd_04.las to fetch Header --------------------------------------------------------- Clipping file to the extent --------------------------------------------------------- minx: 412725.875000 miny: 4532149.500000 minz: 0.000000 maxx: 412860.343750 maxy: 4532359.500000 maxz: 0.000000 --------------------------------------------------------- Writing output: - : /home/peter/Desktop/04_0.las 0... and $ lasinfo ~/Desktop/04_0.las lasinfo ~/Desktop/04_0.las --------------------------------------------------------- Header Summary --------------------------------------------------------- Version: 1.0 Source ID: 0 Reserved: 0 Project ID/GUID: '00000000-0000-0000-0000-000000000000' System ID: '' Generating Software: 'TerraScan' File Creation Day/Year: 0/0 Header Byte Size 227 Data Offset: 229 Number Var. Length Records: None Point Data Format: 1 Number of Point Records: 144379 Compressed: False Number of Points by Return: 89804 42205 11178 1192 0 Scale Factor X Y Z: 0.01 0.01 0.01 Offset X Y Z: -0.00 -0.00 -0.00 Min X Y Z: 412726.37 4532149.73 23.14 Max X Y Z: 412860.33 4532359.50 76.27 Spatial Reference: None --------------------------------------------------------- Schema Summary --------------------------------------------------------- Point Format ID: 1 Number of dimensions: 13 Custom schema?: false Size in bytes: 28 Dimensions --------------------------------------------------------- 'X' -- size: 32 offset: 0 'Y' -- size: 32 offset: 4 'Z' -- size: 32 offset: 8 'Intensity' -- size: 16 offset: 12 'Return Number' -- size: 3 offset: 14 'Number of Returns' -- size: 3 offset: 14 'Scan Direction' -- size: 1 offset: 14 'Flightline Edge' -- size: 1 offset: 14 'Classification' -- size: 8 offset: 15 'Scan Angle Rank' -- size: 8 offset: 16 'User Data' -- size: 8 offset: 17 'Point Source ID' -- size: 16 offset: 18 'Time' -- size: 64 offset: 20 --------------------------------------------------------- Point Inspection Summary --------------------------------------------------------- Header Point Count: 144379 Actual Point Count: 144379 Minimum and Maximum Attributes (min,max) --------------------------------------------------------- Min X, Y, Z: 412726.37, 4532149.73, 23.14 Max X, Y, Z: 412860.33, 4532359.50, 76.27 Bounding Box: 412726.37, 4532149.73, 412860.33, 4532359.50 Time: 589039.231020, 589422.198199 Return Number: 1, 4 Return Count: 1, 4 Flightline Edge: 0, 0 Intensity: 1, 860 Scan Direction Flag: 0, 1 Scan Angle Rank: -12, 13 Classification: 1, 2 Point Source Id: 16017, 16019 User Data: 32, 32 Minimum Color (RGB): 0 0 0 Maximum Color (RGB): 0 0 0 Number of Points by Return --------------------------------------------------------- (1) 89804 (2) 42205 (3) 11178 (4) 1192 Number of Returns by Pulse --------------------------------------------------------- (1) 47367 (2) 62012 (3) 30178 (4) 4822 Point Classifications --------------------------------------------------------- 130234 Unclassified (1) 14145 Ground (2) ------------------------------------------------------- 0 withheld 0 keypoint 0 synthetic Thanks very much for any guidance you can provide. best, Peter Tittmann UC Davis Geography Graduate Group
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