CopyrightGreenValley International

LiGeoreference V1.0

User Guide

Imprint and Version

Document Version 1.0

Copyright © 2018 GreenValley International, Ltd. All rights reserved. This document may be copied and printedonly in accordance with the terms of the Frame License Agreement for End Users of the related LiGeoreferencesoftware.

Published by:

GreenValley International, Ltd.

Web: https://greenvalleyintl.com

Dear User

Thank you for using LiGeoreference software. We are pleased to be of service to you with LiDAR point cloudgeoreference solutions. At GreenValley International, we constantly strive to improve our products. We thereforeappreciate all comments and suggestions for improvements concerning our software, training, anddocumentation. Feel free to contact us via info@greenvalleyintl.com. Thank you.

Legal Notes

GreenValley International® and LiGeoreference® are registered trademarks of GreenValley International. Allother product names, company names, and brand names mentioned in this document may be trademarkproperties of their respective holders.

All rights reserved.

© 2018 GreenValley International, Ltd.

Date printed: 9th May 2018

IntroductionLiGeoreference is a LiDAR point cloud georeferencing software developed independently by GreenValleyInternational which allows users to merge range measurements collected by mobile, UAV or airborne laserscanning systems with position and orientation information recorded by integrated IMU and GNSS sensors. Thisflexible software solution outputs 3D point clouds in .las and .LiData file formats (LiData file format can be openedin GreenValley International’s LiDAR360 software instantly) with LiDAR returns mapped to a user-specifieddatum, including WGS84, projection, and coordinate system (e.g. UTM). Point clouds can also be attributed withRGB imagery using LiGeoreference’s data fusion capabilities to produce a true-color 3D model of an object orarea surveyed. LiGeoreference can transform and process data collected by Riegl, Velodyne, Hesai and otherwidely-used laser scanning technologies. LiGeoreference is now available as a stand-alone application with ahelpful graphical user interface as well as a command-line interface for scripting and easy integration with thirdparty software.

LiDAR technologies exploit the relationship between light’s constant velocity and time to produce highly accurateand precise measurements of variable distances or ranges. Remote-sensing systems used to generate LiDARdata emit infrared and/or visible wavelengths of electromagnetic energy from an optically-focused laser in shortbursts or pulses that are then returned to the broadcasting unit’s integrated photon sensors by signal-reflectingobjects. The laser pulse returns are then accurately mapped to 3D space by merging the LiDAR data withinformation from inertial measurement units (IMU), which determine a LiDAR sensor’s orientation about the X, Yand Z axes. These orientations are also typically referred to as the roll, the pitch, and the yaw or heading angles,respectively. External and/or internal GNSS equipment can also be used to determine the geographic locations ofthe LiDAR system as it collects data. During post-processing, information from the LiDAR sensor, or laserscanner, the IMU, and the GNSS systems must be methodically merged to determine the trajectories of the 3Dmapping system while it moved about the survey area collecting data. This is a critical step in producing accuratedatasets from laser scanning systems mounted on mobile, UAV, or airborne platforms.

InstallationDownload the latest version of LiGeoreference from the GreenValley International official website beforeinstallation.

System Requirements

RAM: at least 16G or more.CPU: Intel® Core™ i5/i7; Dual-core processor.Display Adapter: NVIDIA graphics card recommended, video memory no less than 2GB.Operating Systems: Microsoft Windows 7 (64-bit), Microsoft Windows 8 (64-bit), Microsoft Windows 10(64-bit), Microsoft Windows Server 2012 and higher.

Setup

1. Run the LiGeoreference Setup Wizard.2. Click Next button in the Welcome Interface.3. Click I Agree button to continue if you accept the License Agreement.4. Choose the installation path (or use default path), then click Install button.5. Click Finish button after installation.

License

The license (key file) is generated from user information. LiGeoreference can be activated in the following way:

1. Run the software as administrator.2. The activation window will pop out.3. Fill in user's Name (Mandatory) and Company (Mandatory), then click the Copy for E-mail button.4. Send an E-mail with the copied content to info@greenvalleyintl.com to require a key file.5. After receiving the key file, put the key file in the installation directory.

Note: Please contact info@greenvalleyintl.com for inquiry and purchase.

LiGeoreferenceThis chapter introduces the parameter setting interface and principle of LiGeoreference software in detail.

Input Files & Output

Trajectory

Scanner Installation

Camera Installation

Region of Interest

Coordinate System

Processing & Result

2.1 Input Files & Outputs

Date of Data: Record the date of data collection. The date should be UTC time. Laser scan data collectedfrom GreenValley International’s LiAir systems will have laser scan files named using a convention that relieson the UTC timestamps. As examples, 2017-12-17-12-28-50.pcap means the LiDAR data was collected onDecember 17, 2017 whereas a file named 171010_010128_Scanner_1.rxp would represent data collectedon October 10, 2017 by a Riegl laser scanner.

Instrument: Select the type of laser scanning instrument used for collecting LiDAR data.Velodyne-VLP16（default setting in LiGeoreference）Velodyne-HDL32Velodyne-VLP32CHesai-Pandar40Riegl

Add: Add one or more laser scanning files of the corresponding instrument type to a LiGeoreference project.

Delete: Remove one or more laser scanning files from a LiGeoreference project.

Clear: Remove all laser scanning files in a LiGeoreference project.

Output Directory: Select the output file directory where the georeferenced 3D point cloud data will be savedto once a LiGeoreference software run has completed. Then choose to export the georeferenced point clouddata as a .las or .LiData formatted file.

2.2 Trajectory

Trajectory File：Select the trajectory file to be imported to LiGeoreference. A trajectory file contains thetimestamps, position information (longitude, latitude, elevation) and orientation information (roll angle, pitchangle, heading angle). The format of the trajectory file can be *.pos, *.out, *.pof, or *.txt.

Leap Seconds：This parameter applies a temporal correction from the input laser scanner point cloud datato the timestamps of the associated trajectory dataset. Because point cloud data timestamps are in UTCweek seconds formats, the timestamps of the trajectory data may be GPS time or UTC time (GPS time =UTC time + Leap Seconds). Users can add the Leap Seconds to correct the point cloud data’s timestamps tocorrespond to the trajectory data’s timestamps. Moreover, some RIEGL instruments have thesynchronization offset. The specific values are provided by the instrument supplier. Users must add thissynchronization offset to set the number of seconds.

2.3 Scanner Installation

In the process of georeferencing LiDAR point cloud data the coordinates of the laser returns are transformed fromthe laser scanner’s reference coordinate system to the coordinate system of the mobile, UAV, or airborneplatform from which it was collected. (the original O: The x-axis points through the nose of the craft, The y-axispoints to the right of the x-axis (facing in the pilot's direction of view), perpendicular to the x-axis. The z-axispoints down through the bottom the craft, perpendicular to the xy plane and satisfying the RH rule). A rotationmatrix and a translation matrix is required to make the transformation between the laser scanning referenceframe and the body frames. The following figure is the body coordinate system.

Rotate the z-axis, x-axis and y-axis of the laser scan datasets reference coordinate system in a counter-clockwisesequence of transformation operations. Velodyne and Riegl provide a corresponding product manual.

The laser returns coordinates in the laser scanning reference coordinate system is , and in the bodycoordinate system is .

where， ，among them,y,x and z are rotation angles Pitch, Roll, Heading respectively.

Laser Rotation Matrix：The rotation angle z, x and y are determined according to the installation mode ofthe laser.Once established,the rotation matrix R can be determined.N

X Translation：The coordinate origin of the laser scanning reference frame is transferred to the Xcoordinate translation amount of the carrier coordinate system.

Y Translation：The coordinate origin of the laser scanning reference frame is transferred to the Ycoordinate translation amount of the carrier coordinate system.

Z Translation：The coordinate origin of the laser scanning reference frame is transferred to the Zcoordinate translation amount of the carrier coordinate system.

Roll Calibration Offset：The default calibration parameters depend on the measurement system and areeither zero,specified by the hardware manufacturer or determined by a calibration process.

Pitch Calibration Offset：The default calibration parameters depend on the measurement system and areeither zero,specified by the hardware manufacturer or determined by a calibration process.

Heading Calibration Offset：The default calibration parameters depend on the measurement system andare either zero,specified by the hardware manufacturer or determined by a calibration process.

Import：The parameter files of the laser installation mode can be imported to configure the parameters. Thisis convenient for user settings.

Export：Users can export the parameter file of this installation mode,in order to directly import theparameter files for future configuration.

2.4 Camera Installation

In the process of colorizing laser scan data, 3D point clouds should be transformed from the camera coordinatesystem to the body coordinate system. Rotate the z-axis, x-axis and y-axis of camera coordinate system counter-clockwise in sequence, at a certain angle Heading, Roll, and Pitch, then the point is transformed into the bodycoordinate system. The coordinates of the laser point in the camera coordinate system is , and in thebody coordinate system is .

where, ，among them, y, x and z are rotation angles Pitch, Roll, Heading respectively.

Camera File：The file containing the camera exposure info *.cam.

Image Folder：Directory containing images.

Whether an intermediate file is used：Checked by default, use the config last time (camera file + imagefolder).

Camera Rotation Matrix：The rotation angle z, x and y are determined according to the installation mode ofthe camera. Once established, the rotation matrix R can be determined.

X Translation：The coordinate origin of the laser scanning reference frame is transferred to the Xcoordinate translation amount of the carrier coordinate system.

Y Translation：The coordinate origin of the laser scanning reference frame is transferred to the Ycoordinate translation amount of the carrier coordinate system.

Z Translation：The coordinate origin of the laser scanning reference frame is transferred to the Zcoordinate translation amount of the carrier coordinate system.

Roll Calibration Offset：The default Calibration parameters depend on the IMU or INS measurementsystem and are either zero, specified by the hardware manufacturer or determined by a calibration process.

Pitch Calibration Offset：The default Calibration parameters depend on the IMU or INS measurementsystem and are either zero, specified by the hardware manufacturer or determined by a calibration process.

Heading Calibration Offset：The default Calibration parameters depend on the IMU or INS measurementsystem and are either zero, specified by the hardware manufacturer or determined by a calibration process.

Import：The parameter settings of a specific camera installation can be imported to LiGeoreference usingthis function.

Export：The parameter settings of a specific camera installation can be exported from LiGeoreference usingthis function.

Camrera Intrinsic Parameters：specified by the hardware manufacturer.

2.4.1 Pinhole Camera Model

OPENCV provide detailed description of the camera imaging principle.

N

2.4.2 Functions of Pinhole Camera Model

where, is the coordinate of a point in the camera coordinate, are the focal lengths expressed inpixel units, is a principal point that is usually at the image center, are radial distortioncoefficients, are tangential distortion coefficients, is the coefficient of deformation in CCD plane.

2.5 Region of InterestRiegl and Velodyne laser scan data can filter the specific information that the user requires for LiGeoreference torun. All filters are unchecked by default. Check the box next to each filter option to include it in a LiGeoreferencerun.

Filtering options for datasets generated by Riegl are shown below.

Filtering options for datasets generated by Velodyne laser scanners are shown below.

Filter by Reflectance：Only applies to Riegl laser scan datasets. Only laser returns falling between, or atthe minimum and maximum reflectance return parameter values, will be included in the georeferencedoutput. By default, the range of reflectance is set from -15 to 5.

Filter by Amplitude：Only applies to Riegl laser scan datasets. Only laser returns falling between the

minimum value and maximum amplitude value will be included in the georeferenced output.By default, therange of amplitudes included in the output is set from 0 to 50.

Filter by Distance：This filter will exclude points not falling within the Start and End Distance (meters) rangefrom the georeferenced output. Right click on the blank area of the filter table to display a menu with "Add"and "Remove" options. Click “Add” to set Start and End Distances. Click “Remove” to delete a Start or EndDistance that has already been set.

Filter by Angle：This filter will exclude points not falling within the Start and End Angle (degrees) rangefrom the georeferenced output. Right click on the blank area of the filter table to display a menu with "Add"and "Remove" options. Click “Add” to set Start and End Angles. Click “Remove” to delete a Start or EndAngle that has already been set. A 0 degree Start or End Angle will fall on the right-side of the headingdirection while a 360 degree Start or End Angle will lie on the left-side of the heading direction. Anglemeasures increase in the clockwise direction from 0 to 360 degrees.

Split by GPS Time：This filter will exclude points not falling within the Start and End GPS timestamp rangefrom the georeferenced output. Right click on the blank area of the filter table to display a menu with "Add"and "Remove" options. Click “Add” to set Start and End Times. Click “Remove” to delete Start or End Timesthat have already been set. A single laser scan file can be divided into several segments by adding multipleGPS Start and Stop Times.

Filter by Extent：This filter will only include points falling within the two corners of the rectangle defined interms of longitude and latitude in georeferenced output. Use the radio button to select "degree" if the inputformat is “degree”, then select "d.mmss" to indicate that the input format is degree. Input minutes andseconds (for example, 34.0605 indicates 34 degrees, 6 minutes, 5 seconds).

Filter by Laser Line：Only applies to Velodyne and Hesai laser scan datasets. Each laser line in a givenscanner fires light pulses at a fixed angle. In certain situations it is desirable to only include a portion of thelaser lines or channels that contributed data to the input point cloud in the georeferenced output dataset.

Checking the box next to the Line ID will include data from that laser channel in the output.

2.6 Coordinate System

By default a laser scan dataset will have its point coordinate values converted into a UTM projected coordinatesystem developed on a WGS 84 datum. If users want to get the point cloud data in other specific coordinatesystems, it is necessary to set the parameters of the reprojection. The coordinate system function can alsotransform an input point cloud into other user-specified coordinate systems. When different geographiccoordinate systems are converted to each other, the ellipsoids and the reference surfaces are different sotransformation between the ellipsoids will occur. The seven-parameter-transformation model is provided inLiGeoreference.

Using Seven Parameters: User decides whether to use seven parameters for reprojection. If checked,seven parameters will be used.

Seven Parameter Setting: Select the use seven parameters option. Click the Seven Parameter Settingbutton and the Seven Parameter dialog will pop up. The Add, Save and Clear buttons can be used to addparameters from a text file, save the user-defined parameters to a text file and clear all input parametersrespectively.

Filtering: Users need to input the customized coordinate system. By inputting coordinate system keywords,the corresponding coordinate system can be filtered from the Coordinate Reference System table (forexample: to set the point cloud coordinate system to WGS 84 / UTM Zone 49N, users can enter UTM 49N inthe filter for fast screening or enter its EPSG number: 32649 for quick search.) Users can also import thecoordinate system from the outside by clicking the Add Coordinate System button.

Hide Deprecated CRSs：Hide obsolete coordinate systems. An obsolete coordinate system is a coordinatesystem that has fallen into disuse or has been replaced by a newer or more accurate coordinate system.However, obsolete coordinate systems may still be found in historical sources of data and thus remainrelevant in certain instances.

Select CRS：If a coordinate reference system has been selected, its name and details will be displayedhere.

2.7 Processing & Result

Log：This window will include a print out of the processing results and can be a helpful resource forLiGeoreference users attempting to troubleshoot any issues.

Thread Number：The number of threads used by the software to run LiGeoreference. The default value of 2is recommended for most systems.

Export Json：Save configuration parameters to Json file, which can be used in command line mode. If thetrajectory file is in .POS format, the import POS dialog will first appear to configure each column of POS dataand then export the .Json format file.

Command Line: Run LiGeoreference with cmd and pass the parameter. Parameters are “-j” and Json file.The Json file can be exported by Export Json and edited by user. For example:

2.7.1 Import POS Dialog

After clicking "Finish", the software will pop up the POS file preview window shown below.

The corresponding properties can be selected in each drop-down box.

Generally, software can automatically identify the separator of a file, or select the corresponding separator atSeparator.

Ignore the data: Users can ignore the header and other unwanted data by choosing to skip line X at Skiplines.

2.7.2 Image Matching Dialog

This dialog pops up when the image folder does not match the number of records in the .cam file. The left side ofthe dialog is the .cam file information list. The first column contains ID, the second column exposure times asSeconds in a Day, the third column is the time interval between the current data and the previous row of data.The right side of the dialog lists the images stored in the image folder. The first column contains ID, the secondcolumn exposure times as seconds in a Day, the third column is The time interval between the current data andthe previous row of data.

when the Image Matching dialog box appears (shown below) the user must perform a manual match byfollowing Steps 1-5 below. If the Image Matching dialog does not appear, no manual match is required.

1.As shown below, the drop-down dialog box looks at 364 rows on the left and 362 rows on the right.

2.Pull down from the first line and find where the first time-interval is changed, as shown below.

As seen above, line 77 is on the right and the time-interval is 7 seconds, while the left is line 79. That means thecam file has 2 more records in Top 79 lines or images has 2 less records in Top 77 lines, After correcting thelines, you can view the image information for confirmation the issue has been resolved.

3.In this case, the first 2 rows on the left are redundant. Uncheck them and the dialog will show the "match"status, as per the illustration below:

Top Radios: "Not Thinning": not thinning data, "Take1/2" thinning by 1/2, draw a picture in one picture. "Takeout a third" thinning by 1/3, draw one from two pictures.

AppendixThis chapter describes in detail the file format used by this software.

Abbreviations/Glossary

POS

OUT

POF

SDC

CAM

CAMINFO

Abbreviations/Glossary

Body coordinate system

This is the Cartesian coordinate system attached to the aircraft. The most commonly used is the NED (North-East-Down) where the x-axis points to the nose, the y-axis to the right wing, and the z-axis downwards. Applyingthe roll, pitch, and yaw angles of the POS data file to this body coordinate system brings the system axes parallelto north, east, and down, respectively.

SOCS

The laser scanner's own coordinate system，denoted in the laser scanners manual.

UTC

Coordinated Universal Time is the primary standard by which the world regulates time.

WGS84

World Geodetic System 1984. Reference system for the Global Positioning System (GPS) since 1987. It definesa reference frame for the Earth, a Geodetic Datum as well as an Earth reference ellipsoid. In the context of thisdocument it is in some cases used as synonym for any geocentered GD.

SOW

Within each week, GPS time is usually denoted as the second of the week (SOW) or a number between 0 and604,800 ( 60 seconds/minute x 60 minutes/hour x 24 hours/day x 7 days/week).

Timestamp

A highly accurate time descriptor, that specifies output by the GNSS (e.g. GPS) receiver and is derived from theGNSS's own atomic clock time base. In the RIEGL ALS System timestamp data is added to every lasermeasurement.

GPS

Global Positioning System. Currently the only fully functional Global Navigation Satellite System (GNSS). Itutilizes a constellation of at least 24 medium Earth orbit satellites that transmit precise microwave signals. Thesystem enables users to determine their position, velocity, and time anywhere in the world.

POSThe POS File contains a lot of information, GPS time, longitude, latitude, height, roll, pitch, heading, GridX andGridY.GPS time, longitude, latitude, height, roll, pitch and heading must be included, GridX and GridY areoptional.

The following is part information of the POS file.

Example 1(not include GridX，GridY):

380954.000,112.5311950876, 26.8969520123,378.543, 7.1701230000, 3.0890110000,-39.4065340000 380954.008,112.5311938923, 26.8969533249,378.537, 7.2001860000, 3.0914780000,-39.4034150000 380954.016,112.5311926975, 26.8969546376,378.531, 7.2368710000, 3.0936380000,-39.4011190000 380954.024,112.5311915034, 26.8969559507,378.525, 7.2683090000, 3.1015050000,-39.3975470000 380954.032,112.5311903098, 26.8969572641,378.518, 7.3007560000, 3.1115160000,-39.3929590000 380954.040,112.5311891169, 26.8969585779,378.512, 7.3269790000, 3.1179720000,-39.3878260000 380954.048,112.5311879247, 26.8969598920,378.506, 7.3525870000, 3.1180460000,-39.3804020000 380954.056,112.5311867331, 26.8969612065,378.500, 7.3745730000, 3.1151630000,-39.3713830000

Example 2(include GridX，GridY):

383207.336,112.5421590662,26.9034172036,313.865,3.538615,2.660518,-67.848653,653147.099716932,2976670.62354689383207.344,112.5421572108,26.9034177865,313.861,3.533299,2.659177,-67.840828,653146.914649722,2976670.68587654383207.352,112.5421553554,26.9034183697,313.857,3.522385,2.658042,-67.828619,653146.729582108,2976670.74823943383207.36,112.5421535001,26.9034189529,313.854,3.512757,2.659231,-67.816251,653146.544524429,2976670.81060244383207.368,112.5421516447,26.9034195363,313.85,3.502656,2.662677,-67.807435,653146.35945655,2976670.87298749383207.376,112.5421497892,26.9034201198,313.846,3.502243,2.664987,-67.803265,653146.174378605,2976670.9353835383207.384,112.5421479336,26.9034207035,313.843,3.500293,2.668456,-67.80232,653145.989290462,2976670.99780155383207.392,112.5421460783,26.9034212874,313.839,3.501546,2.671267,-67.797563,653145.804231844,2976671.06024212383207.4,112.5421442231,26.9034218713,313.835,3.496569,2.674773,-67.789195,653145.619183163,2976671.12268281383207.408,112.542142368,26.9034224554,313.832,3.483849,2.676885,-67.774991,653145.434144147,2976671.18514579383207.416,112.5421405129,26.9034230395,313.828,3.471533,2.676137,-67.765536,653145.24910513,2976671.24760876383207.424,112.5421386577,26.9034236237,313.824,3.47028,2.675779,-67.760612,653145.064056049,2976671.3100827383207.432,112.5421368024,26.9034242079,313.82,3.475101,2.677064,-67.761833,653144.878997039,2976671.37255652383207.44,112.5421349471,26.9034247923,313.817,3.476053,2.681571,-67.761664,653144.69393776,2976671.43505249

OUTAs a format of the trajectory file, *.OUT is a kind of binary file. The following table shows the format of thePOSPac SBET file provided by Applanix. For details, refer to the PosPac quick start guide.

The trajectory information stored in its file is structured as follows:

Data Units Type

time seconds double

latitude radians double

longitude radians double

altitude meters double

x velocity meters/second double

y velocity meters/second double

z velocity meters/second double

roll radians double

pitch radians double

platform heading radians double

wander angle radians double

x body acceleration meters/second² double

y body acceleration meters/second² double

z body acceleration meters/second² double

x body angular rate radians/second double

y body angular rate radians/second double

z body angular rate radians/second double

POFDESCRIPTION OF POF (POSITION&ORIENTATION) FILE FORMAT

Introduction

The binary POF-Format (Position & Orientation Format, .pof) replaces the former POS-Format and allows fastersearch for time stamps.

Timestamps are stored as normseconds [normsecs] within the file. This time format is equivalent to UTC weekseconds with only one exception: The first day is the date specified in the header (fields YEAR, MONTH andDAY) whereas UTC week seconds always start on Sunday. Using this mechanism a rollover / overflow can beavoided and implementation of faster search algorithms is possible (binary search, interpolation search).

With the following formula norm seconds [normsecs] can be converted into UTC week seconds [weeksecs]:

int Days = Floor(NormSecs/86400.0);

double Secs = NormSecs - (Days*86400.0);

double WeekSecs = Secs + (DayOfWeek(Date)+Days mod 7) * 86400.0;

Note: DayofWeek(Date) = 0(Sun), 1(Mon),...,6(Sat)

General header structure

The file starts with the Ascii-String 'RIEGL POSITION&ORIENTATION' terminated by Ascii-Zero <0x00>:

RIEGL POSITION&ORIENTATION<0x00>

Now the major.minor version information follows (binary, Little Endian, 2 bytes unsigned integer each):

(MAJOR:u2)(MINOR:u2)

Definition of version 1.0 and 1.1

The data offset (binary) specifies the position of the first data record in the file:

Data Meaning Type

DATAOFFSET data offset u4

YEAR The creation year of the trajectory u2

MONTH The creation month of the trajectory u2

DAY The creation day of the trajectory u2

ENTRIES Number of entries (data records) n8

MINLON minimum longitude(degree) d8

MAXLON maximum longitude(degree) d8

MINLAT minimum latitude(degree) d8

MAXLAT maximum latitude(degree) d8

MINALT minimum altitude(m) d8

MAXALT maximum altitude(m) d8

AVGINT average time interval(sec) d8

MAXINT maximum time interval(sec) d8

DEVINT standard deviation of jumps(sec) d8

TIMEUNIT 0(normsecs),1(daysecs)),2(weeksecs) u1

TIMEINFO 0(GPS),1(UTC),2(unknown) u1

TIMEZONE time zone 16

LOCATION location 32

DEVICE navigation device 32

RESERVED reserved 32

PROJECT project name 32

COMPANY company name 32

RESERVED reserved for future use 101

Note: The TIMEUNIT field only stores the time format of the original data input (e.g. using our POFImportsoftware). This field is used for information only or when exporting the data (ASCII format, ...)

In the data records time stamps are always stored as norm seconds!

Data records version 1.0

Every data record represents a measurement from the IMU/GPS unit:

Data Units Type

TIME second double

LON degree double

LAT degree double

ALT m double

ROLL degree double

PITCH degree double

YAW degree double

56 bytes record size

Data records version 1.1

Every data record represents a measurement from the IMU/GPS unit:

Data Units Type

TIME second double

LON degree double

LAT degree double

ALT m double

ROLL degree double

PITCH degree double

YAW degree double

DIST m double

64 bytes record size

Note：u = unsigned integer (little endian), n = signed integer (little endian), d8 = double precision floating point(little endian)

SDCThe extracted data files (.sdc, .sdw) contain one record for every target detected in the sample data. The binaryrecord data format is different for the different file types and is described below in more detail. Apart fromadditional valuable information on the detected targets such as amplitude of the reflected echo signal, temporalwidth of the echo signal, and target number within one laser measurement (first, second, .. last target), therecords contain geometry data in different coordinate systems and different data formats.

SDC files additionally contain range and scan angle data for each target.

SDC record formats:

TRecord_5_4 = packed record // SDC 5.4

Data Meaning Type

TIME seconds of the day or of the week double

RANGE measured range value(m) float

THETA measured theta value(degree) float

X x coordinate(m) float

Y y coordinate(m) float

Z z coordinate(m) float

AMPLITUDE linearized amplitude unsigned short

WIDTH width of target return unsigned short

TARGETTYPE 0(COG),1(PAR),2(GPF),3 to 5(GPE) unsigned char

TARGET index of target unsigned char

NUMTARGET total number of targets unsigned char

RGINDEX range gate index of measurement unsigned short

CHANNELDESC channel descriptor unsigned char

CLASSID class identifier unsigned char

RHO tile mount angle(degree) float

REFLECTANCE reflectance short int

Note:

If the SDC file has been created from an .rxp (V-line) file, WIDTH contains the deviation of the target echo!

If created from an .sdf file (Q560, Q680 family), WIDTH contains the width of the target pulse as described above.

The deviation has no physical unit but describes the "quality" of the echo pulse. Usually this values is below 30.

CAMIn the cam file, each row is separated by comma. Sequentially, this is displayed as Serial number, cameranumber, trigger time, return time with End flag "*", Where the trigger time is stated, the return time format isddmmss.sss，and is UTC time. For example,"44008.001" means 04 hours 40 minutes 08.001 seconds.

Example 1, below, shows a section of information from the cam file:

#Item:00003, Camera:01, Trig:44008.001, FB:44008.077 *#Item:00004, Camera:01, Trig:44010.001, FB:44010.078 *#Item:00005, Camera:01, Trig:44012.001, FB:44012.077 *#Item:00006, Camera:01, Trig:44014.001, FB:44014.076 *#Item:00007, Camera:01, Trig:44016.001, FB:44016.077 *#Item:00008, Camera:01, Trig:44018.001, FB:44018.076 *#Item:00009, Camera:01, Trig:44020.001, FB:44020.076 *

CAMINFOcaminfo.txt is the intermediate result file of the software. Each row is separated by a comma to sequentially showtime (seconds of day in UTC) and image name.

Example 1, below, shows the caminfo.txt file:

16808.1,DSC00001.JPG16810.1,DSC00002.JPG16812.1,DSC00003.JPG16814.1,DSC00004.JPG16816.1,DSC00005.JPG16818.1,DSC00006.JPG

FAQ

Why is the result size 1KB?

Invalid filtering rules.

Normally, the start and end time of trajectory and the start and end time of each laser file are prompted bythe log. If the time range of the laser file is not within the time range of the trajectory, the size of the result filewill be 1KB. please confirm whether the Date of Data in the software interface is correct. In the examplebelow, the time period of the trajectory is 175344.001-184407.005, while the beginning and termination timeof laser file are -1. The time period of the laser file is not in the time period of the trajectory, so the result is1KB.

If log have abnormal reminders, will they affect the results?

When there is abnormal information in the log, the software log window will display “WARNING” in red. Thisindicates the software has encountered an exception to the data but this generally does not affect thegeoreferencing results. This is shown in the figure below:

As seen above and below, the software log window is displaying an error in red. This indicates that theGeoreference has an inaccuracy. Generally, the correct result cannot be output. Users need to rectify.

What causes the serious deformation of the result?

The serious deformation of the result is usually caused by an error in the Laser Rotation Matrix setting, and itneeds to be rearranged according to the installation of the instrument. The following map shows that the pointcloud display is obviously inconsistent with the actual objects.

Why do objects in the result have a wavy appearance??

This is usually caused by an incorrect leap seconds setting. The time of the point cloud in the software will betransformed to UTC time. Please confirm that the POS time is UTC time or GPS time. If the POS time is UTCtime, the leap seconds should be set to 0, otherwise it should be set to -18. Note that some RIEGL instrumentshave the synchronize-offset. This synchronize-offset value is provided by the instrument supplier. Users need toadd this synchronization-offset to the leap seconds.

What is the possible reason for the lack of power line in the results?

The filtering condition is used to remove the noise. If the filter condition settings do not suit the actual situation,the power line point cloud will be determined as noise and thus removed. In this case, no filtering conditions needto be set to resolve the data. If the power line point cloud is not missing, the unsuitable filtering condition is thereason for the loss of the power line point cloud, and suitable filtering conditions need to be set. If there is still alack of power line point cloud, This means data was lost during the acquisition process and software cannot solvethis problem.

What causes the misalignment of power lines near the tower?

This is caused by the aircraft hovering near the tower, resulting in the POS jump. The result depends on the POSinformation, so the point cloud will be misplaced. This software cannot resolve this issue.

What is the timestamps of the point cloud?

The timestamps of the point cloud is corresponding to the POS.

How do you solve the colorless process in the Camera parameters

Check whether the Camera Installation is checked.Check the Camera File and whether there is data in the Image Folder.Check whether the Split by GPS Time is used, and if there is a matching image in the selected time period.

Why is the result not correct?

If the color result is incorrect, this is usually due to the wrong setting in Camera Rotation Matrix.If the result of coloration is only moving along the flight direction, it may be caused by mismatched imagedata and Cam file information.

Why can't you switch language types

The software supports Chinese and English and sets the software language according to the computer systemlanguage. If the computer system language is Chinese, the type of software language is Chinese, otherwise it isEnglish.

Why can’t the LiData result format be opened by LiDAR360?

There may not be enough space in the result path disk, which causes errors in writing LiData data. Please makesure that there is enough disk space.