SMS:Scatter Menu: Difference between revisions

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The items in the Scatter menu in the Scatter module are described below. The  menu items all work with the active scatter set unless otherwise noted.
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The items in the ''Scatter'' menu in the Scatter module are described below. The  menu items all work with the active scatter set unless otherwise noted.


= General Commands =
Listed below are the general commands in the ''Scatter'' menu.
==[[SMS:Scatter Options (Data Menu)|Scatter Options]]==
===Scatter Options===
Scatter options are accessed through the Scatter menu, Scatter Options dialog  in the Scatter Module.


===Triangulation Options===
Scatter options are accessed through the ''Scatter'' menu, [[SMS:Scatter Options|''Scatter Options'']] dialog  in the Scatter Module.


This section lets the user adjust the maximum aspect ratio of a thin  triangle. The aspect ratio is the ratio of the triangle width to the triangle  height. All triangles with an aspect ratio less than what is specified are  considered thin.
===Merge Scatter Sets===
[[Image:Scatter Merge Sets.png|thumb|375 px|Scatter Module ''Merge Scatter Sets'' dialog]]
Multiple scatter sets can be merged into a single scatter set using the ''Merge Scatter Sets'' dialog. The menu command ''Scatter'' | '''Merge Sets''' opens the ''Merge Scatter Sets'' dialog.
==== Selecting scatter sets to merge ====
The ''Merge Scatter Sets'' dialog contains a spreadsheet listing all of the scatter sets currently loaded into SMS. Scatter sets to merge are specified by checking the ''Merge'' box in the ''Merge column'' of the spreadsheet. When merging scatter sets, only one dataset is transferred to the merged scatter set. The dataset to be transferred is specified for each scatter set in the ''Dataset'' column of the spreadsheet.


===Long Triangles===
The ''Priority'' column of the spreadsheet is only used if the overlapping region option is set to ''Delete lower priority scatter points''. This option is explained below.


This section contains options for deleting or selecting long triangles.
==== Merge Options ====
 
===Individual Points===
 
This section contains the Retriangulate voids when  deleting option. When scatter points are deleted, the triangles attached  to the scatter points (if any) are also deleted. If this option is on,  surrounding triangles are retriangulated to fill the void.
 
===Triangulation Optimization Options===
When the optimize  triangulation command is invoked, the triangles are optimized in one of two  ways:
* Angle Optimization – The triangles are swapped to  conform to the Delaunay  Criterion.
* Area Optimization (SHOALS) – The triangles are  swapped to align with other triangles. The swapping is done by comparing the  area of one triangle to its neighbor. The user sets a Bias. If the area of the smaller triangle is less than the  area of the larger triangle divided by the bias, the triangles are swapped. This  is useful for optimizing the triangulation of surveys such as SHOALS  surveys.
 
[[Image:Triangulation_optimization.jpg]]
 
===Duplicate Vertex Options===
When the Select/Delete Duplicate  Points menu item is selected, points within a tolerance of other points are  selected or deleted. The user sets the Tolerance and  whether to delete or select the points when the command is invoked.
==[[SMS:Delete Scatter Set|Delete Scatter Set]]==
This option is found in the Scatter module in the  Scatter menu. If one scatter set exists, the user will be asked if they want to  delete the active scatter set. If more than one scatter set exists, a dialog  appears. The scatter sets can be flagged for deletion in this dialog.  Double-clicking on a scatter set in the window or pushing the ''Delete'' button flags or unflags a scatter set for deletion. ''Select All'' or ''Deselect All'' will  flag or unflag all sets. A set is flagged if the letter "d" appears to the left  of the scatter name.
 
==[[SMS:Merge Scatter Sets|Merge Scatter Sets]]==
Multiple scatter sets can be merged into a single scatter set using the Merge Scatter Sets dialog. The menu command ''Scatter | Merge Sets'' opens the Merge Scatter Sets dialog.
 
=== Selecting scatter sets to merge ===
The Merge Scatter Sets dialog contains a spreadsheet listing all of the scatter sets currently loaded into SMS. Scatter sets to merge are specified by checking the Merge box in the Merge column of the spreadsheet. When merging scatter sets, only one dataset is transferred to the merged scatter set. The dataset to be transferred is specified for each scatter set in the Dataset column of the spreadsheet.
 
The Priority column of the spreadsheet is only used if the Overlapping region option is set to ''Delete lower priority scatter points''. This option is explained below.
 
=== Merge Options ===
The following options are available when merging scatter sets:
The following options are available when merging scatter sets:
* ''Name'' – Specify the name for the new, merged scatter set.
* ''Delete original scatter sets'' – The scatter sets to be merged are deleted after the new, merged set is created.
==== Overlapping region options ====
* ''Merge all scatter points'' – All scatter points from all scatter sets to be merged are combined into one set and retriangulated.
* ''Delete lower priority scatter points'' – In regions where scatter points and triangles overlap, the scatter points and triangles from the lower priority scatter set are deleted. The priority is based on the ''Priority'' column of the ''Select scatter sets to merge'' spreadsheet. The '''Move up''' and '''Move down''' buttons can be used to adjust the priority of the scatter sets when this option is selected. When this option is selected, the boundary of the higher priority scatter set is forced into the resulting merged scatter set. If the point spacing along this boundary varies greatly from one scatter set to the other, the result will include skinny triangles, which are not recommended. If the triangles become too skinny, numerical issues may result due to floating point precision round off. To address this, a tolerance is specified to delete points from the lower priority scatter set not just inside the higher priority set, but also points outside the higher priority set but within the specified tolerance of the edge of the higher priority set. This lessens the severity of the ''skinny triangle'' issue.
*:Note: historically it has been common to convert DEM/raster datasets to a scatter set in order to create a continuous surface for interpolation. This workflow can result in scatter sets with millions of points and is not numerically stable or efficient. SMS now supports the use of multiple rasters to represent varied resolution for background data.  A workflow using rasters is recommended in this case.
** ''Maintain triangulation'' – The triangulation of the original scatter sets is maintained. New triangles are created to connect the original scatter sets into a single, merged scatter set.


==== Merged scatter set options ====
====Merge Report====
* '''Name''' – Specify the name for the new, merged scatter set.
When the merge finishes a merge report will be displayed on the screen.  This report shows statistics for the scatter sets that were merge such as number of vertices and triangles before and after the merge.  If desired vertices are being deleted, check the duplicate points tolerance. This is found in the ''Scatter→Scatter Options'' dialog.
* '''Delete original scatter sets''' – The scatter sets to be merged are deleted after the new, merged set is created.
[[File:ScatterMergeReport.png|thumb|none|250 px|The scatterset ''Merge Report'' dialog]]


==== Overlapping region options ====
===Assign Point Name===
* '''Merge all scatter points''' – All scatter points from all scatter sets to be merged are combined into one set and retriangulated.
Active when a scatter point, or group of points, have been selected. This brings up a dialog that allows assigning a unique name to the selected point.
* '''Delete lower priority scatter points''' – In regions where scatter points and triangles overlap, the scatter points and triangles from the lower priority scatter set are deleted. The priority is based on the '''Priority''' column of the '''Select scatter sets to merge''' spreadsheet. The '''Move up''' and '''Move down''' buttons can be used to adjust the priority of the scatter sets when this option is selected.
===Interpolate to===
** '''Maintain triangulation''' – The triangulation of the original scatter sets is maintained. New triangles are created to connect the original scatter sets into a single, merged scatter set.
Bring ups the  [[SMS:Scatter Interpolation|''Interpolation  Options'']] dialog. This dialog is used to interpolate scatter set values to a 2D mesh, Cartesian grid, Ugrid, or quadtree.


===Merge Report===
*2D Mesh – The scatter point [[SMS:Datasets|datasets]] are then interpolated to the mesh nodes using the user specified interpolation options.
When the merge finishes a merge report will be displayed on the screen. This report shows statistics for the scatter sets that were merge such as number of vertices and triangles before and after the merge.  If desired vertices are being deleted, check the duplicate points tolerance. This is found at Scatter→Scatter Options dialog.
* Cartesian Grid – The scatter point function values are then interpolated to the center of each grid cell.
* UGrid – The scatter point function values are then interpolated to the center of each grid cell.


==[[SMS:Create Scatter Subset|Create Scatter Subset]]==
===Interpolate to Scatter===
All selected points from the original scatter set are moved from the original set into a new scatter set. The user is prompted for  the name of the new scatter set. If all points for the current scatter set are  selected, nothing occurs. The two scatter sets, the original and the new, are  retriangulated.
Interpolating on scatter set to another scatter set has three options:
==[[SMS:Interpolate to Mesh|Interpolate to Mesh]]==
====Interpolate to Scatter Grid====
If mesh nodes exist, the [[SMS:Scatter_Interpolation|Interpolation Dialog]] appears where the user sets the interpolation options. The scatter point [[SMS:Data_Sets|datasets]] are then interpolated to the mesh nodes using the user specified interpolation options.
[[Image:Scatter Grid Frame.png|thumb|270 px|''Grid Frame'' dialog]]
==[[SMS:Interpolate to Cartesian Grid|Interpolate to Cartesian Grid]]==
If a scattered dataset exists, the '''Interpolate to Scatter Grid''' menu item (Scatter module, ''Scatter'' menu) brings up the ''Grid Frame'' dialog. This dialog, positions the purple grid frame and sets up the number  of rows and columns in the grid. After clicking'''OK''', a new scatter set is  created with scatter points at the corners of each grid cell. The original scatter set is interpolated to the new scatter grid set using linear interpolation.
If a cartesian grid exists, the Interpolation Dialog appears where the user sets the interpolation options. The scatter point function values are then interpolated to the center of each grid cell.
==[[SMS:Interpolate to  Scatter Grid|Interpolate to Scatter Grid]]==
If a scattered dataset exists, the Interpolate to Scatter Grid menu item (Scatter module, Scatter menu) brings up the Grid Frame  dialog. The user positions the purple grid frame and sets up the number  of rows and columns in the grid. When the user pushes OK, a new scatter set is  created with scatter points at the corners of each grid cell. The original scatter set is interpolated to the new scatter grid set using linear interpolation.


Using the scatter grid is a form of data  decimation: a dense scatter set can be represented as a less dense scatter set.
Using the scatter grid is a form of data  decimation: a dense scatter set can be represented as a less dense scatter set.


==[[SMS:Interpolate to Nautical  Grid|Interpolate to Nautical Grid]]==
====Interpolate from Other Scatter====
This option creates a nautical chart. A nautical chart divides a scatter set into bins and finds the maximum, minimum, and average depth over each bin. The Interpolate to Nautical Grid menu item (Scatter  module, Scatter menu) brings up the Grid Frame dialog. The user positions the purple grid frame and sets up the number of rows and columns in the grid. When the user pushes OK, a new scatter set is created with scatter points at the center of each grid cell. Three functions are created for each scatter point from the active scalar function of the original scatter set:
This option interpolates one scattered dataset to another set. Two sets must exist for this option to be enabled. An ''Interpolation'' dialog appears where the scatter set to interpolate from is selected. That scatter set is interpolated to the active scatter set. The interpolation uses an extrapolation value of "0.0".
 
====Interpolate to Nautical Grid ====  
This option creates a nautical chart. A nautical chart divides a scatter set into bins and finds the maximum, minimum, and average depth over each bin. The '''Interpolate to Nautical Grid''' menu item (Scatter  module, ''Scatter'' menu) brings up the ''Grid Frame'' dialog. The dialog positions the purple grid frame and sets up the number of rows and columns in the grid. After clicking '''OK''', a new scatter set is created with scatter points at the center of each grid cell. Three functions are created for each scatter point from the active scalar function of the original scatter set:
* '''Average''' – The average depth  over each bin.
* '''Average''' – The average depth  over each bin.
* '''Minimum''' – The minimum depth over  each bin.
* '''Minimum''' – The minimum depth over  each bin.
* '''Maximum''' – The maximum depth over each bin.
* '''Maximum''' – The maximum depth over each bin.
 
Requirements to interpolate to a nautical grid include:
=== Requirements to Interpolate to a Nautical Grid ===
# A scatter dataset must exist.
# A scatter dataset must exist.
# Active coverage type must allow grid frames to be created. The Cartesian Grid Module model coverage types allow the creation of grid frames.
# Active coverage type must allow grid frames to be created. The Cartesian Grid Module model coverage types allow the creation of grid frames.


==[[SMS:Interpolate to Scatter Set|Interpolate from Other Scatter]]==
===Interpolate to Map===
This option interpolates one scattered dataset to another set. Two sets must exist for this option to be enabled. A dialog appears and the user selects the scatter set to interpolate from. That scatter set is interpolated to the active scatter set. The Options button brings up the Interpolation Options dialog, allowing the user to set the interpolation type. The interpolation uses an extrapolation value of 0.0.  
This option will assign the elevation values from on scatter set to the active map coverage. The [[SMS:Scatter Interpolation|''Interpolation'']] dialog will appear, where the interpolation method can be selected for assigning elevation data to the map coverage.
 
==Obsolete Commands==
The following commands are no longer available in current released of SMS:
 
; '''Create Scatter Subset''' : All selected points from the original scatter set  are moved from the original set into a new scatter set. A prompt will ask for  the name of the new scatter set. If all points for the current scatter set are  selected, nothing occurs. The two scatter sets, the original and the new, are  retriangulated.
;'''Delete Scatter Set''' : This option is found in the Scatter module in the  ''Scatter'' menu. If one scatter set exists, a prompt will ask if wanting to delete the active scatter set. If more than one scatter set exists, a dialog  appears. The scatter sets can be flagged for deletion in this dialog.  Double-clicking on a scatter set in the window or pushing the '''Delete''' button flags or unflags a scatter set for deletion. '''Select All''' or '''Deselect All''' will  flag or unflag all sets. A set is flagged if the letter "d" appears to the left  of the scatter name.


==Related Topics==
=Related Topics=
* [[SMS:Scatter Module|Scatter Module]]
* [[SMS:Scatter Module|Scatter Module]]
* [[SMS:Scatter_Module_Menus|Scatter Module Menus]]
* [[SMS:Scatter_Module#Scatter_Module_Menus|Scatter Module Menus]]
* [[SMS:Scatter Triangles Menu|Scatter Triangles Menu]]
 


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{{Template:Navbox SMS Menus}}
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[[Category:SMS Scatter]]
[[Category:SMS Scatter|M]]
[[Category:SMS Menus|S]]
[[Category:SMS Scatter Dialogs|Menu]]
[[Category:Needs Update]]
<!--Could use reorganization for consistency and clarity.-->

Latest revision as of 23:37, 6 February 2023


The items in the Scatter menu in the Scatter module are described below. The menu items all work with the active scatter set unless otherwise noted.

Listed below are the general commands in the Scatter menu.

Scatter Options

Scatter options are accessed through the Scatter menu, Scatter Options dialog in the Scatter Module.

Merge Scatter Sets

Scatter Module Merge Scatter Sets dialog

Multiple scatter sets can be merged into a single scatter set using the Merge Scatter Sets dialog. The menu command Scatter | Merge Sets opens the Merge Scatter Sets dialog.

Selecting scatter sets to merge

The Merge Scatter Sets dialog contains a spreadsheet listing all of the scatter sets currently loaded into SMS. Scatter sets to merge are specified by checking the Merge box in the Merge column of the spreadsheet. When merging scatter sets, only one dataset is transferred to the merged scatter set. The dataset to be transferred is specified for each scatter set in the Dataset column of the spreadsheet.

The Priority column of the spreadsheet is only used if the overlapping region option is set to Delete lower priority scatter points. This option is explained below.

Merge Options

The following options are available when merging scatter sets:

  • Name – Specify the name for the new, merged scatter set.
  • Delete original scatter sets – The scatter sets to be merged are deleted after the new, merged set is created.

Overlapping region options

  • Merge all scatter points – All scatter points from all scatter sets to be merged are combined into one set and retriangulated.
  • Delete lower priority scatter points – In regions where scatter points and triangles overlap, the scatter points and triangles from the lower priority scatter set are deleted. The priority is based on the Priority column of the Select scatter sets to merge spreadsheet. The Move up and Move down buttons can be used to adjust the priority of the scatter sets when this option is selected. When this option is selected, the boundary of the higher priority scatter set is forced into the resulting merged scatter set. If the point spacing along this boundary varies greatly from one scatter set to the other, the result will include skinny triangles, which are not recommended. If the triangles become too skinny, numerical issues may result due to floating point precision round off. To address this, a tolerance is specified to delete points from the lower priority scatter set not just inside the higher priority set, but also points outside the higher priority set but within the specified tolerance of the edge of the higher priority set. This lessens the severity of the skinny triangle issue.
    Note: historically it has been common to convert DEM/raster datasets to a scatter set in order to create a continuous surface for interpolation. This workflow can result in scatter sets with millions of points and is not numerically stable or efficient. SMS now supports the use of multiple rasters to represent varied resolution for background data. A workflow using rasters is recommended in this case.
    • Maintain triangulation – The triangulation of the original scatter sets is maintained. New triangles are created to connect the original scatter sets into a single, merged scatter set.

Merge Report

When the merge finishes a merge report will be displayed on the screen. This report shows statistics for the scatter sets that were merge such as number of vertices and triangles before and after the merge. If desired vertices are being deleted, check the duplicate points tolerance. This is found in the Scatter→Scatter Options dialog.

The scatterset Merge Report dialog

Assign Point Name

Active when a scatter point, or group of points, have been selected. This brings up a dialog that allows assigning a unique name to the selected point.

Interpolate to

Bring ups the Interpolation Options dialog. This dialog is used to interpolate scatter set values to a 2D mesh, Cartesian grid, Ugrid, or quadtree.

  • 2D Mesh – The scatter point datasets are then interpolated to the mesh nodes using the user specified interpolation options.
  • Cartesian Grid – The scatter point function values are then interpolated to the center of each grid cell.
  • UGrid – The scatter point function values are then interpolated to the center of each grid cell.

Interpolate to Scatter

Interpolating on scatter set to another scatter set has three options:

Interpolate to Scatter Grid

Grid Frame dialog

If a scattered dataset exists, the Interpolate to Scatter Grid menu item (Scatter module, Scatter menu) brings up the Grid Frame dialog. This dialog, positions the purple grid frame and sets up the number of rows and columns in the grid. After clickingOK, a new scatter set is created with scatter points at the corners of each grid cell. The original scatter set is interpolated to the new scatter grid set using linear interpolation.

Using the scatter grid is a form of data decimation: a dense scatter set can be represented as a less dense scatter set.

Interpolate from Other Scatter

This option interpolates one scattered dataset to another set. Two sets must exist for this option to be enabled. An Interpolation dialog appears where the scatter set to interpolate from is selected. That scatter set is interpolated to the active scatter set. The interpolation uses an extrapolation value of "0.0".

Interpolate to Nautical Grid

This option creates a nautical chart. A nautical chart divides a scatter set into bins and finds the maximum, minimum, and average depth over each bin. The Interpolate to Nautical Grid menu item (Scatter module, Scatter menu) brings up the Grid Frame dialog. The dialog positions the purple grid frame and sets up the number of rows and columns in the grid. After clicking OK, a new scatter set is created with scatter points at the center of each grid cell. Three functions are created for each scatter point from the active scalar function of the original scatter set:

  • Average – The average depth over each bin.
  • Minimum – The minimum depth over each bin.
  • Maximum – The maximum depth over each bin.

Requirements to interpolate to a nautical grid include:

  1. A scatter dataset must exist.
  2. Active coverage type must allow grid frames to be created. The Cartesian Grid Module model coverage types allow the creation of grid frames.

Interpolate to Map

This option will assign the elevation values from on scatter set to the active map coverage. The Interpolation dialog will appear, where the interpolation method can be selected for assigning elevation data to the map coverage.

Obsolete Commands

The following commands are no longer available in current released of SMS:

Create Scatter Subset
All selected points from the original scatter set are moved from the original set into a new scatter set. A prompt will ask for the name of the new scatter set. If all points for the current scatter set are selected, nothing occurs. The two scatter sets, the original and the new, are retriangulated.
Delete Scatter Set
This option is found in the Scatter module in the Scatter menu. If one scatter set exists, a prompt will ask if wanting to delete the active scatter set. If more than one scatter set exists, a dialog appears. The scatter sets can be flagged for deletion in this dialog. Double-clicking on a scatter set in the window or pushing the Delete button flags or unflags a scatter set for deletion. Select All or Deselect All will flag or unflag all sets. A set is flagged if the letter "d" appears to the left of the scatter name.

Related Topics