Data Acquisition: Explanation of TIN/TILE Filters

Elisabeth Pry — Fri, 21 Jun 2013 14:08:28 GMT

Current Revision posted to OpenRoads | OpenSite Wiki by Elisabeth Pry on 6/21/2013 2:08:28 PM


	Applies To

	Product(s):	InRoads
	Version(s):	08.11.07+
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A
	Original Author:	Bentley Technical Support Group

The Difference Between the TIN and TILE filters in Data Acquisition

The Tile Filter uses an algorithm that divides the LIDAR data set into tiles. A best fit plane is calculated for each tile, and LIDAR points are removed if they fall within the user set Z tolerance to the plane.

The TIN Filter first separates the LIDAR points into tiles with a maximum of 2 million points and then repetitively triangulates each tile, filtering out points. The TIN Filter algorithm filters out the points if they fall within the user set Z tolerance of the triangle planes.

Z Tolerance - common to both algorithms and is basically the variation in the Z coordinate that the surface is allowed to move during the filtering process. Typically for the first invocation of the filtering function, the Z tolerance should be set from 0.5 to 1.0 for imperial data sets and from 0.25 to 0.5 for metric data sets. Depending on the outcome and the desired result, the Z tolerance can be varied up or down.

Max. Tile Points - specifies that a tile will not be subdivided if it has less than this number of points. Typically this is set to five.

Max. Tile Divisions - the allowable level of recursion allowed and is the number of time the initial tiling set can be subdivided. Typically this is set to five.

Start Tile Length – The LIDAR data set is initially divided into tiles of this size, prior to recursion to the minimum tile points. The setting of this parameter requires some knowledge of the distance between the LIDAR points, which requires an inspection of the LIDAR points in MicroStation to determine. Typically set this to 10 times the distance between the LIDAR points.

Course Filter (TIN option only) – Filter more points with some blurring of ridges and valleys

Fine Filter (TIN option only) – Filters fewer points with less blurring of ridges and valleys

Points Before Filter/Points After Filter/Reduction % - Display of the number of points before and after filtering, plus the percentage reduction of points from before and after

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Tags: InRoads, SELECTservices, TechNote

Data Acquisition: Explanation of TIN/TILE Filters

Jacquelyn Pettus — Fri, 22 Feb 2013 20:38:54 GMT

Revision 3 posted to OpenRoads | OpenSite Wiki by Jacquelyn Pettus on 2/22/2013 8:38:54 PM

Document Information

Document Type: TechNote

Product(s): InRoads

Version(s): V08.11.07+

Original Author: Bentley Technical Support Group

The Difference Between the TIN and TILE filters in Data Acquisition

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Data Acquisition: Explanation of TIN/TILE Filters

Jacquelyn Pettus — Fri, 22 Feb 2013 20:37:31 GMT

Revision 2 posted to OpenRoads | OpenSite Wiki by Jacquelyn Pettus on 2/22/2013 8:37:31 PM

Document Information

Document Type: TechNote

Product(s): InRoads

Version(s): V08.11.07+

Original Author: Bentley Technical Support Group

The Difference Between the TIN and TILE filters in Data Acquisition

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Data Acquisition: Explanation of TIN/TILE Filters

Jacquelyn Pettus — Fri, 22 Feb 2013 20:34:26 GMT

Revision 1 posted to OpenRoads | OpenSite Wiki by Jacquelyn Pettus on 2/22/2013 8:34:26 PM

<h5><a href="http://selectservices.bentley.com/en-US"><img src="/Other/Old_Site_Files/Bentley_Folders/m/support/17560/download.aspx" border="0" width="175" height="56" /></a></h5>
<h1>Document Information</h1>
<blockquote>
Document Type: TechNote 
Product(s): InRoads 
Version(s): V08.11.07.428
Original Author: Bentley Technical Support Group
<h1> </h1>
</blockquote>
<h3 style="margin: 0in 0in 10pt; text-align: center;"></h3>
<h3 style="margin: 0in 0in 10pt; text-align: center;"></h3>
<h1 style="margin: 0in 0in 10pt; text-align: center;" align="center">How to work with Point Cloud data in InRoads<o:p></o:p></h1>
<h4 style="margin: 0in 0in 10pt; text-align: center;"></h4>
<h4 style="margin: 0in 0in 10pt; text-align: left;">Import Point Cloud Data into MicroStation<o:p></o:p></h4>
First, the data must be imported into MicroStation’s Point Clouds command.  Tools > Point Cloud > Point Clouds will bring up the Point Clouds command or “manager”.
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/0317.1-Attach-File.JPG" border="0" />
From here, use the File > Attach method to receive the Open dialog.  Search for the file that is to be imported.  File types that can be imported are the following:  
Pointools POD (*.POD)
Terrascan BIN (*.BIN)
Topcon CL3 (*.CL3)
Faro FLS (*.FLS)
Faro FWS (*.FWS)
LAS (*.LAS)
Leica PTG (*.PTG)
Leica PTS (*.PTS)
Leica PTX (*.PTX)
Riegl 3DD (*.3DD)
Riegl RDB (*.RDB)
Riegl RXP (*.RXP)
Riegl RSP (*.RSP)
Generic Text (*.XYZ)
Generic Text (*.TXT)
All Files (*.*)

<h4>Converting file to *.POD</h4>
<span style="font-size: 11pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">After selecting the file to import, a dialog will appear that asks if the file is to be converted.  
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/0550.2-Convert-POD.JPG" border="0" />
This is where the file can be converted to a *.POD file and where options can be specified for converting the data.  If this is something to be worked on over time, it is required to convert the file to a *.POD format for later usage.  
<o:p> </o:p>
<h4>View Attributes<o:p></o:p></h4>
To show the different attributes for the point cloud, go to Settings > View Attributes > Point Cloud Presentation > Style.<o:p></o:p>
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/3678.3-View-Attributes.JPG" border="0" />
Drop-down menu allows to choose the point cloud display style.<o:p></o:p>
·         None — No display attribute is applied to the point cloud; points of the cloud display as white points. 
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/6403.4-none.JPG" border="0" />
·         RGB per Point — Point clouds display according to their RGB attributes. Not all point clouds contain RGB attributes but if they are present, each point of the cloud has a RGB color. (In this dataset, there are no RGB attributes assigned)<o:p></o:p>
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/6470.5-RGB.JPG" border="0" />
·         Classification — Some point clouds contain classification attributes. At present, only the attributes coming from LAS files can be imported. (In this dataset, the attributes are elevations)<o:p></o:p>
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/5381.6-classification.JPG" border="0" />
 ·         Elevation — Used to color the point cloud relative to its height (or width or depth, depending on the chosen axis). <o:p></o:p>
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/5282.7-elevation.JPG" border="0" />
 ·         Intensity — Represents the strength of the signal returned by the laser scanner. 
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/6763.8-Intensity.JPG" border="0" />
 
<h4>Import Point Cloud into Data Acquisition<o:p></o:p></h4>
Go to Tools > Data Acquisition to open the command.  When there is a fence defined, Data Acquisition will automatically honor that fence during the import process.  *To work with manageable surfaces in InRoads/GEOPAK/MX, fences will be required to generate the surfaces.*
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/1145.9-Import-PC.JPG" border="0" />
 After selecting the option “Import From Point Clouds”, a Point Clouds Surface dialog should appear to select filters and tolerances.  The filter button will display the results prior to selecting “Accept”.  Once the filters have been approved, select “Accept”.
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/5482.a1-Accept.JPG" border="0" />
<h4> </h4>
<h4>Export Surface</h4>
Data Acquisition can export surfaces in four different formats:  GEOPAK TIN, InRoads DTM, MX Modelfile, and LandXML.
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/6560.a2-export-DTM.JPG" border="0" />
In this workflow, an InRoads DTM surface was created.  Once selecting the proper export format, the Save As dialog will appear to save the file.  <o:p></o:p>

More workflows on Data Acquisition can be found in the following location:
<a title="Data Acquisition Workflows" href="/products/road___site_design/w/road_and_site_design__wiki/data-acquisition-support-videos.aspx" target="_blank">Data Acquisition Workflows</a>
<h4></h4>
<h4>Open Surface in InRoads<o:p></o:p></h4>
<span style="font-size: 11pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">The surface may now be opened into InRoads with the new file type of *.DTM.
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/8105.a3-Open.JPG" border="0" />
 Notice the screenshot below.  These graphics were displayed using the InRoads’ command Surface > View Surface > Features.  This is only a portion of the point cloud data.  Again, to work with manageable surface, fences will be required during import process in to Data Acquisition.
<img src="/resized-image.ashx/__size/550x0/__key/CommunityServer-Wikis-Components-Files/00-00-00-00-52/0257.a4-features.JPG" border="0" />
 
<h3></h3>
<h3></h3>

<h1></h1>
<h1>See Also</h1>
<a href="/Products/w/Products__Wiki/product-technotes-and-faqs.aspx">Product TechNotes and FAQs</a>
<a href="/Products/Road___Site_Design/w/Road_and_Site_Design__Wiki/inroads-product-technotes-faqs-and-support-video-clips.aspx">InRoads Product TechNotes FAQs And Support Video Clips</a>
<h1>External Links</h1>
<a title="KnowledgeBase" href="http://appsnet.bentley.com/kbase/">Bentley Technical Support KnowledgeBase</a>
<a title="LEARN Server" href="http://lms.bentley.com">Bentley LEARN Server</a>
<h1>Comments or Corrections?</h1>
Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!
 
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