When Perspective is first installed all internal settings are in a default state, the screenshots in the guide show these default settings. Once a setting has been changed its condition is persisted so that when Perspective is next run the settings will be preserved. Under normal circumstances it should not be necessary to access the files that maintain the settings.
To return the application to its default state you can safely delete all XML configuration files with the exception of those noted below:
autoUpdatePath.xml; ellipsoids.xml; nad27.xml; nad83.xml; splashScreenSample.xml; symbols.xml
On a system running Windows Vista the files will can be found here:
C:\Users\<User Name>\ AppData\Local\Triton Imaging, Inc\Perspective\
A system running Windows XP will have the files located here:
C:\Documents and Settings\<User Name\Local Settings\Application Data\Triton Imaging, Inc\Perspective
The file licdump.txt is also written to the same location as the XML files. Problems with licensing can usually be resolved by emailing customer support, support@tritonimaginginc.com with a description of the problem, attach licdump.txt to the mail.
Start Perspective and click Import>Raw Data File, you can also "drag and drop" a selection of files directly on to the Perspective map window:
Whichever method is used the Importing Files... progress bar is displayed. The two smaller progress bars will only be displayed if you have told Perspective that your system has multiple processors (e.g. an Intel® Core™ 2 Duo processor), any tasks that are suitable for multiple processor functions will take advantage of this feature. Go to View>Settings Info... and selected the number of Cores.
After all lines have been imported and the cache file for each line has been written, the display shows the navigation track for each line. The lines will be listed under the Navigation Node in the Tree View.
In this example the XTF files contained Sidescan data, the first option is to process that data. In the guide we are processing only the Bathy data, hit Skip.
The next dialog allows you to chose between:
Skip: Display only the navigation data (you can add bathy data later)
Use Wizard: Setup all the processing stages to generate a DTM for the first time.
Use Previous Settings: Assumes that you have already successfully processed some data and you now want to add more XTF files and process them in exactly the same way with the stored settings (see above).
Hit Use Wizard:
The Choose/Create Bathy Layer Dialog opens
Hit Create and enter the name of the *DTM that you want to create - (in this case "bathydata"), note that the extension .tmap_dtm is added automatically.
*DTM: Digital Terrain Model, stored in Triton Perspective as <file name>.tmap_dtm
Hit Save
You now have the opportunity to select any/all of the lines for which navigation is available, Select all Deselect all or check individual lines, hit Next to proceed.
Vessel Geometry: Use vessel geometry from XTF header.
The default is to use the offsets that were written into the XTF file at the time the data were logged. Unchecking this option allows you to either Load or Create a different Vessel Geometry (.GEO) file see below for detailed information.
GSF: Include FTS when available.
All data is written internally to a standard GSF (Generic Sensor Format) file. Footprint Time Series data is beam imagery from within each beam footprint, sometimes called Snippets. If the data contains this information then leaving the box checked will generate both a DTM and imagery from the FTS data in the GSF file.
This type of data requires a great deal of processing and the size of the XTF files can be very large. Unless there is a requirement for snippet imagery the box should be unchecked.
HTF: Generate HTF
Check this box and hit Settings to save an HTF file.
The details of the Vessel Geometry should be entered at this time, hitting the Create button displays the Vessel Geometry dialog. Note that if there had been any information in the header of the XTF files it would be already visible in these dialog boxes.
Enter the XYZ offsets for each part of the system relative to the Reference Point (RP). The Roll, Pitch and Yaw offsets are those derived from the Patch Test and represent the angular misalignment between the motion sensor and the sonar head. The diagram shows the sign convention used. Heave Reference can be either the motion sensor or the transducer. Ref.Height is the height of the Reference Point (RP) above the waterline.
Latency offsets refer to the latency of the various sensors that are in use. Note that Depth latency refers to the latency of the pressure (depth) sensor when processing data from a multi beam echo sounder mounted in a towed vehicle (ROV or AUV) - this feature is not implemented in the current release.
When all offsets are entered, click OK. You MUST save the offsets to a .GEO_xml file.
Enter a name for the .GEO file and click Save
Hit Next to open the Gridding of Soundings dialog:
Resolution enter the resolution of the DTM that you need, you should choose something appropriate having regard to the expected water depth and number of beams. This is also the "bin" size into which the raw bathy sounders will gridded. The smaller this figure is the larger will be the file size of the final DTM file and the longer will be the processing time.
Encoding choose from:
Last: the last value to fall in the bin being processed.
Max: the deepest value to fall in the bin being processed.
Min: the shallowest value to fall in the bin being processed.
First: the first value to fall in the bin being processed.
Average: the average of all the values that fall in the bin.
Constrain to map view: Only process the data that falls inside the current map window.
Depth limit: choose the correct range for the data. If the data falls both deeper and shallower than 2000m choose >2000m
Fill Filter: turn this on to fill gaps between data points, the two settings allow either a Median or Inverse Distance filter to be used to compute the value of the depth being created. Also the size (number of bins) East-West and North-South that will be used.
Smooth Filter: A low-pass filter that can be applied to the DTM. The variables are similar to the Fill Filter. Use this filter with care, useful data can easily be removed!
Hit Next to go to the Raw Processing dialog:
Precise Timing Architecture check this option if the data you are processing was acquired with a Reson Sonar and POS/RAW navigation attitude and heading data from an Applanix® POS/MV sensor. This setting will take advantage of the precise timing link that exists between the Reson Multibeam Sonar and the POS sensor.
Navigation Processing the box is checked by default. The standard setting will apply a boxcar filter of 12 navigation updates to create a running mean position. Click the Settings button to access more options:
NOTE: The navigation is only processed in the cache file that is associated with each XTF file, the cached data is used in the bathy processing routines.
Window - the boxcar filter size, increase for heavier smoothing set to 1 for no smoothing.
Source:
Sensor - read the navigation data found in the Sensor position in the XTF file.
Ship - read the navigation data found in the Ship position in the XTF file.
Smoothed - read the smoothed navigation from the cache (.XTF_idx) file.
Heading:
Compute course made good - compute a course made good (CMG) from the navigation data, write this to the cache and use as the heading source in processing.
Bias - apply a Bias to the CMG calculation.
Layback: Applicable only to towed systems, not implemented in this release.
Speed: apply a Max/Min speed filter to the navigation.
Compute: compute speed,
Never - use the speed that was logged in the XTF file.
Always - ignore the speed from the XTF and compute new speed.
When zero - only compute speed when the value in the XTF file is zero.
Mag Heading: Applicable only to towed systems having fluxgate compasses, not implemented in this release.
Hit OK to go to the Beam Suppression Dialog
Note the default settings, reject only beams that are flagged as Bad by the sonar.
Suppress Using Beam Quality
The bathy data sent from the sonar will have some flags that have been set by the sonar, these are the Beam Quality flags Poor, Low, Bad. The user can choose to reject more data based on these flags.
Suppress Beams Outside Angle
Suppress beams that fall outside an angle that the user may choose, allows potentially noisy outer beams to be rejected.
Suppress Beams Using Depth Range
Suppress beams that fall outside the expected depth range for the survey.
Suppress Beams Using Gradient
Suppress beams that generate exceed a predetermined value for adjacent beams.
Suppress Beams Inside Angle
Sonars that use the phase comparison method have very poor data directly below the transducer, this option allows that area to be suppressed.
Suppress Beams Using Slant Range
Suppress beams that exceed a predetermined value for slant range. For example the sonar range (slant range) may be set to 100m but all data beyond 80m is noisy.
Hit Next to continue to the SVP Processing dialog:
NOTE: SVP, Tide, and Squat files that are read by Perspective are .XML files created from the Raw ASCII data by the XML Utilities program, the files are parsed in the XML utilities application.
Turn ON SVP processing with the check box, there are two ways to read the data, either by a folder of files with SVP data from different times during the survey, or by selecting a specific file.
Files that are read successfully will generate a graph, you can click on a list of SVP files to compare the graphs, double clicking the small graph window will display a large, resizable version:
If the cast has both Up and Down components then these are displayed as dark blue Down and lighter blue Up.
Sample from: There are choices to use either the Upcast, the Downcast or the Merged value from both.
Velocity sampling: Choose whether to use the Mid-Sample value or the actual Sample.
Refraction at transducer depth from.
Off: use the value supplied by the sonar head sensor
CTD: use the value supplied by an external CTD sensor and logged in the XTF file as Sound Velocity.
SVP: use the information read from the SVP graph for transducer depth.
Single Beam (manual entry): Enter a mean value for single beam data processing.
Hit Next to go to the Tide/Squat Processing Dialog
The dialog is very similar to the SVP dialog, once again either a single tide file can be chosen or a folder of tide files from different locations. If there is more than one tide file then Perspective will process using the closest three tide stations that have tide dates and times that cover the time of the survey data. The tide used is the distance-weighted average of the three closest tide stations. Each tide file can be selected and a green bar will show the current period of the bathy data within the tide data. Covers survey time in green will be displayed.
If a tide file that does not cover the survey period is selected then Outside Survey Time is displayed in red:
Use RTK Tides: checking this box will cause Perspective to look for Antenna Height in the XTF file logged from an RTK navigation system in the Ocean Tide section of the XTF file. The data in the XTF file are the raw antenna height from the navigation data, not corrected for station height relative to the tidal datum. The user will need to reprocess the DTM to take account of this vertical offset. (or include the offset in the Vessel Geometry)
Squat Table: Click the Use checkbox and select the squat table .squat.xml generated from XML Utilities.
Click Finish to start Processing.
The program will make a few basic checks on the information entered, for example if Precise Timing had been chosen in the Navigation processing dialog and the XTF files did not contain PosRaw data the following message might be displayed:
Hit OK and start over - use the Create DTM toolbar button:
which will return you to the Choose/Create Bathy Layer Dialog
Once everything is OK processing of the data starts and several progress bars will display in succession:
Finally the processed DTM will be displayed:
Cache file - the first time any raw data file is imported into Perspective a cache file is written. In the case of an XTF file the cache will have the same name as the XTF file but the file extension will be .XTF_idx. The files are created alongside the original XTF file in the same folder. This implies that the the media upon which the XTF file exists must be write-enabled (for example you cannot import directly from a CD or DVD). Using a cache file speeds up access time and allows modifications to be made without changing the original arw XTF. If necessary these cache files cane be safely deleted Perspective will automatically create new ones as necessary.