Untitled :: OpenCPN Plugins Manual

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Ocpn_Draw 1.6

Developer: Jon Gough

Summary

The Ocpn_Draw Plugin (OD) is designed to allow users to place objects/items on the OpenCPN interface and have these georeferenced. This allows the objects/items to move with the chart and have a defined Latitude and Longitude. There are two basic types of object/item that can be used:

Points
Paths

Points are very similar to Waypoints and mark locations on the chart. Paths join two or more points together and draw a line between them. Currently these Points exist:

Boundary Point (BP)
Text Point (TP)
Electronic Bearing Line (EBL) Point
Dead Reckoning (DR) Point
Guard Zone (GZ) Point

These Points are used to construct special types of Paths:

Boundary (B)
Electronic Bearing Line (EBL)
Dead Reckoning (DR)
Guard Zone (GZ)
Parallel Index Line (PIL)

The example screen shot below shows an example of each type of Point and Path.

One user’s Feature Request:

“When Piloting the Range and Bearing of prominent bouys, chart features can be temporarily important as is the balance of the traffic. AIS proves the real time value of plotting these dynamic elements. Additionally, this point is reinforced where (Cursor) Range and Bearing is shown in places like the Dashboard or Status Bar. However, when piloting in unfamiliar waters it is useful to maintain an awareness of multiple landmarks. Much of the dead reckoning situational awareness in the absence of AIS targets is from Range and Bearing info, especially at night or in low visibility. A big benefit with respect to maintenance of situation awareness on deck. These range and bearing datapoints might be recorded/timestamped when arriving at designated DR waypoints as well. Range/Bearing Also, Useful when estimating arrival at a layline, given a known tacking angle and current heading”

His Comment after learning of ODraw:

“Thanks for the redirect. ODraw_PI works great for my purposes. We should definitely CLOSE this request….”

Integration with other plugins

WatchDog Alarms

Ocpn_Draw_pi (OD) provides a graphics companion to Watchdog_pi (WD) Alarms. OD is used as a graphics tool to create Boundary Graphics and Boundary Point Graphics. WD will then create “Boundary Alarms” using the Boundary Graphics created by OD. The alarms that WD can create are (GPS proximity, GPS course & time, Anchor, AIS) depending on the alarm type WD may require a particular Boundary GUID or the alarm may apply to all boundaries that are displayed. The WD alarm types are separate and distinct from the OD graphics types (inclusive, exclusive, neither). OD knows nothing about the WD plugin, it just responds with information about specific Lat/Lon combinations. WD can use the graphic type that OD has to help filter which boundaries to look for. So if you have a large number of boundaries of mixed 'types' it would probably help if you selected the type of boundary to look for rather than use the default 'Any'.

ODraw and WatchDog interactions

See plugin_messaging between ODraw , Watchdog and Weather_routing. A simple way to visualise the interactions between ODraw Boundaries and WatchDog boundaries alarms is laid out in this chart.

The chart shows which OD Boundary objects will cause a WD alarm to ring. If the WD alarm is set to Exclusion, the alarm will ring, go off, if an Exclusion boundary is found within the alarm area, i.e. time or distance. However, no other type of boundary will cause the alarm to go off. So when you setup the alarms you need to check the above matrix to ensure you will get the alarm when you want it.

You can set up multiple Dynamic Guard Zones and set the alarms for one, some or all of these zones.

(Dynamic) Guard Zone Alarms are in some ways similar to the “AIS Collision Alarm” you can set in OpenCPN (Options-Ships-AIS Targets-CPA Calculation). But they are more versatile.

Weather routing integration

Red hatched Boundary created with Ocpn_Draw and used in Weather Routing Configuration > Options > Basic Tab > Check “Detect Boundary”

Squiddio integration

An extended API has been provisioned to allow other plugins to interact with the objects that OD supports. A new version of the Squiddio plugin is available which can make use of OD Text Points for the display of information. This removes the Squiddio waypoints from OCPN and replaces them with OD Text Points. This has the effect of decluttering the OCPN Routes and Waypoints Manager dialog. There is a new, extended, preferences dialog for Squiddio that allows the user to set various paramters for use with OD.

As can be seen it is easy to change between OCPN and OD for the display of Squiddio information. The extra information below the selection of which component to use is a subset of the settings available for Text Points. To find out more about Text Points please read further down on the manual.

Import Draw Objects

There are currently two different format files that allow importing of Draw objects, these are: gpx and csv. Examples of both formats can be found here: https://github.com/jongough/ocpn_draw_pi/tree/master/examples. Both of these formats allow you to generate Draw objects from other data sources and then import them rather than having to create each object then modify them to get the correct attributes.

GPX

The gpx format is an XML format file and is exactly the same as used by Draw for storing its objects over a restart. If you look in the 'ocpn_draw_pi/data' directory you will see one or more xml files these show all the attributes needed for creating a gpx file. Or if you want to generate your own gpx file then do an export of a single Draw object of the type you would like to import so that you have the complete structure which you can then modify and import. The following is an example (test export paths1.gpx):

<?xml version="1.0"?>
<OCPNDraw version="0.1" creator="OpenCPN" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:opencpn="http://www.opencpn.org">
  <opencpn:ODPoint lat="-22.966665000" lon="153.702456667">
    <opencpn:type>Boundary Point</opencpn:type>
    <time>2018-01-08T07:57:51Z</time>
    <opencpn:boundary_type>Exclusion</opencpn:boundary_type>
    <sym>Triangle</sym>
    <opencpn:guid>24ed5a17-c01e-477a-a51b-dfa3368b6ba0</opencpn:guid>
    <opencpn:viz>1</opencpn:viz>
    <opencpn:viz_name>0</opencpn:viz_name>
    <opencpn:arrival_radius>0.000</opencpn:arrival_radius>
    <opencpn:ODPoint_range_rings visible="false" number="0" step="1" units="0" colour="#FF0000" width="2" line_style="100" />
  </opencpn:ODPoint>
  <opencpn:ODPoint lat="-23.182036667" lon="153.635186667">
    <opencpn:type>Boundary Point</opencpn:type>
    <time>2018-01-08T07:57:52Z</time>
    <opencpn:boundary_type>Exclusion</opencpn:boundary_type>
    <sym>Triangle</sym>
    <opencpn:guid>4013a102-5ac4-47b0-a14a-bd2c3d3197be</opencpn:guid>
    <opencpn:viz>1</opencpn:viz>
    <opencpn:viz_name>0</opencpn:viz_name>
    <opencpn:arrival_radius>0.000</opencpn:arrival_radius>
    <opencpn:ODPoint_range_rings visible="false" number="0" step="1" units="0" colour="#FF0000" width="2" line_style="100" />
  </opencpn:ODPoint>
  <opencpn:ODPoint lat="-23.327897169" lon="153.454901890">
    <opencpn:type>Boundary Point</opencpn:type>
    <time>2018-01-08T07:57:53Z</time>
    <opencpn:boundary_type>Exclusion</opencpn:boundary_type>
    <sym>triangle</sym>
    <opencpn:guid>39b37b4d-568d-406d-8a18-214d467181f0</opencpn:guid>
    <opencpn:viz>1</opencpn:viz>
    <opencpn:viz_name>0</opencpn:viz_name>
    <opencpn:arrival_radius>0.000</opencpn:arrival_radius>
    <opencpn:ODPoint_range_rings visible="false" number="0" step="1" units="0" colour="#FF0000" width="2" line_style="100" />
  </opencpn:ODPoint>
  <opencpn:ODPoint lat="-23.295772262" lon="153.282689914">
    <opencpn:type>Boundary Point</opencpn:type>
    <time>2018-01-08T07:57:54Z</time>
    <opencpn:boundary_type>Exclusion</opencpn:boundary_type>
    <sym>triangle</sym>
    <opencpn:guid>24ea8aca-a730-4bb9-b3df-15db1267b19d</opencpn:guid>
    <opencpn:viz>1</opencpn:viz>
    <opencpn:viz_name>0</opencpn:viz_name>
    <opencpn:arrival_radius>0.000</opencpn:arrival_radius>
    <opencpn:ODPoint_range_rings visible="false" number="0" step="1" units="0" colour="#FF0000" width="2" line_style="100" />
  </opencpn:ODPoint>
</OCPNDraw>

CSV

The CSV format file is to allow you to use a spreadsheet program to easily generate objects. Here is an example (test-boundary-import.csv):

'c', 'type(B)','name', 'boundary_type', 'visible(t/f)', 'line rgb-colour', 'rgb-fill-colour'
'B','test boundary1','Exclusion','t','rgb(0,255,0)','rgb(255,0,0)'
'c', 'type(BP)', 'name', lat, lon, 'boundary_type', 'visible', 'rings-visible(t/f)', 'rings-number', 'rings-step', 'rings-units(N/K)', 'rings-colour'
'BP','first',-23.00,154.00
'BP','second',-23.5,154.00
'BP','third',-23.5,154.50
'BP','fourth',-23.0,154.50
'/B'
'B','test boundary2','Exclusion'
'BP','first',-22.00,154.00
'BP','second',-22.5,154.00
'BP','third',-22.5,154.50
'BP','fourth',-22.0,154.50
'/B'
'BP','isolated',-22.70,154.70
'c', 'type(TP)', 'name', lat, lon, 'position (t/ct/b/cb/c/r/l)', 'show (a/r/n)', 'visible (t/f)', 'display text'
'TP','my test text point',-22.70,154.70,'cb','a','t','this is one long line and should be treated as such. It is not designed to wrap'
'TP','my multiline text point',-22.90,154.70,'cb','a','t','this is not one long line\n and should not be treated as such.\nIt is designed to wrap'

The first label describes the type of line that follows, i.e. 'c' is a comment, 'B' is a Boundary, etc.

Using this format in a spreadsheet will allow you to easily create multiple Draw objects and then import them when you have finished.

Installation

This version of the plugin requires at least version of OpenCPN 5.xx.yy. It is not compatible with any version before this. The reason is that the user interface changed with OCPN 5 and a new graphics library was used.
Download the plugin from the Plugin Downloads section of opencpn.org

Interface Icons

When OCPN_DRAW_PI is installed and activated you will see two new icons in the OpenCPN Toolbar, they will always appear together, but depending on the other plugins that are currently active may appear in different positions within the toolbar.

image::od_toolbar_icons.png[image,width=44,height=71]OCPN Toolbar icons

The top icon is for the Draw Paths and Points Manger, the bottom icon is the Draw tool that was last used. It can be any of the tools from the Draw Toolbar below.

image::od_toolbar.png[image,width=239,height=69]Draw Toolbar

Depending on the settings you have chosen for Draw this toolbar may never be displayed, displayed whilst a drawing tool is in use or always displayed. There are 7 icons to choose between and each activates a different tool. The currently active tool icon will also show in the OCPN Toolbar when you are drawing. If you have finished drawing the last active tool is shown in the OCPN Toolbar for easy, quick, access to the last tool.

Draw Create (bottom icon)

The plugin has an interesting interface with two icons as shown above for Draw Manager and Draw Create . The bottom icon on the OCPN Toolbar, Draw Create, is dynamic and will show a different icon depending on which drawing object type has been selected. Click on the bottom icon on the OCPN Toolbar and a floating Draw Toolbar appears containing Draw Tools , with the last one used selected by default (appears depressed). Select the Drawing Tool needed. The above Draw Tools are for Boundary, then Boundary Points, Text points, EBL, DR, Guard Zone, and Parallel Index Line in that order. The Drawing Objects that are available are as follows:

Boundary
Boundary points
Text points
Electronic Bearing Lines (EBL) & Variable Range Marker (VRM)
Dead Reckoning
Guard Zone (GZ)
Parallel Index Line (PIL)

Try drawing several of each type to learn how they work and what they create. You can select the next tool in sequence by right clicking the mouse prior to starting to draw. Once a left mouse click has been done the right click will terminate the 'create' drawing. You can also stop the 'create' mode by hitting 'Esc', left mouse clicking the selected tool in the main toolbar or by left mouse clicking on the close icon in the 'Draw Toolbar'. It sounds complicated, but you will find one of the methods should meet your normal usage requirements.

Each tool has a cursor icon:

Boundary: Pencil
Boundary Point: Red Cross
Text Point: 'I' icon
EBL: Red Cross and a line joining the cursor to the boat
DR: Red Cross
GZ: Pencil
PIL: Red Cross

The DR tool does not draw based on the current cursor position, it brings up a dialog box that allows you to enter the DR information.

When you left mouse click 'OK' the DR line will be drawn based on the information you have entered. The information that is first displayed is the default information entered into the properties panel or the current information available to OpenCPN, i.e. SOG and COG.

Draw Manager (top icon)

The top Icon is for the Draw Manager which gives the user control over each of the Drawing objects that have been created from the Draw Toolbar. Left click on the Drawing Manager menu and the Path & OD Point Manager dialog will be displayed. The Path & Point Manager has tabs for Paths, OD Points and Layers from which selected Drawing Objects can be Shown, Hidden, Deactivated, Centered, Deleted, Exported, Delete All, and Export All. Additionally a drawing object’s Properties can be accessed and changed. First select one or more Drawing Objects under a given Tab . Then select the desired Action on the right. For example: Select all Drawing Objects under Paths Tab , then select Delete . This will remove all of the Drawing Objects under Path Tab . Of course the quick alternative is to select Delete All . Properties, Deactivate and Center View are greyed out when more than one object is selected.

Drawing Manager > Layers

Drawing Objects imported into Layers are static and non editable. Use Layers in the same way as the OCPN Route and Waypoint manager does, i.e. Temporary Layers. It will bring in boundaries and points and show or hide them as required. You can load more than one layer file into the same layer, just select more than one file in the file manager popup and they will load into the same layer. To use Layers and move Drawing Objects into a temporary user created Layer, select them, Export Selected and then import then from the Layers tab Import.

Edit Mode for Draw Objects

First, if you are in the 'create' mode you must terminate this by, Right Click of mouse, button, Left Click on the tool you are using or hit 'Esc' on the keyboard. Then in the drawing hover over the object you wish to modify until a square yellow descriptor appears, then right click. The popup menu’s first line will identify the type of drawing object you have selected. Then there will be a action pick list, dependent on the object, such as Properties, Move.., Insert.. Deactivate.. Delete. Some drawing objects are made of several parts, (Boundary, Boundary Points, EBL & VRM, GZ and PIL) so it makes a difference where you hover and the condition of the object.
1. To select a Boundary, hover over the edges. To select a boundary point hover over it.
2. To select an EBL hover over the ends or the shaft, depending on whether the EBL is centered on a boat or lat/long the right click actions will be different. The popup menu list selections should be self explanatory.

When you have right clicked and selected an action, for example to move a boundary, text point or boundary point, the point will be highlighted with a yellow dot. Complete the move by dragging and releasing. For editing any characteristics such as color, line thickness, font, etc, use 'Properties', but if you just want to move a point select 'Move'. To move a point you will need to right click and select move. Having selected move you will then need to put the cursor over the selected object, push and hold the left mouse button and drag the object to where you want it. When you let go of the left mouse button the cursor (what ever it was showing before) should revert to the standard pointer and the 'move' process is terminated. If you want to move the object again, you will have to right click again to get the popup and repeat the process.

Edit Mode for Draw Object Properties

There are multiple ways to access an object’s Properties .

In Path & Point Manager double click on a Drawing Object, Properties will appear.
In the Drawing hover over the Drawing Object, right click and pick Properties .
In the Drawing hover over the Drawing Object, double left click, Properties will appear.

It is also possible to drill down into an object if it is multi-part, i.e. get a Boundary properties dialog displayed then right click or double click any line showing a Boundary point and the properties for that point will be displayed.

Constrained moves

When moving an object you can move it in any direction just by holding the left hand mouse button down and dragging. If you want to constrain the movement to horizontal or vertical you need to use the Ctrl key to only allow vertical movement or the Shift key to only allow horizontal movement. If you release the key whilst dragging the constraint is removed. You can press and hold one of the two keys at any time during the movement, the constraint only applies when the key is held down. Additionally, when used with EBL pressing Ctrl + Shift at the same time, will constrain the angle value and allow movement along the angle. This will also work when perpendicular line is checked.

Whole Boundary moves

A boundary can be moved as a single object or a single line of the boundary can be moved. The default action is to move the whole boundary, but you can select 'Move Boundary Segment' from the right mouse button popup menu.

Boundary merges

If you have two or more boundaries you can select these and merge the boundaries together. This is accomplished by hold the Ctrl key down then left mouse clicking on the boundaries you want to merge. Each boundary selected will flicker showing it has been selected. If you then right click on a boundary you will be presented with a merge popup. This will allow you to merge and keep the current boundaries, this draws a bounding boundary around the selected boundaries. If you select merge and delete you will draw a bounding box around the boundaries then the original boundaries will be deleted. There is no undo, so care needs to be taken.

Available Drawing tools

This section will describe in more detail the drawing tools that are available with this Plug In.

Boundary

This allows drawing of a closed path joining all points that of the path. The smallest Boundary has two points, but normal Boundaries will have three (triangle) or more points. There is no limit to the number of points, or the size of the Boundary. When drawing points that have already been placed will be connected togther with the path line. A rubber band line will be drawn that follows the cursor. The boundary fill may appear incomplete or strange at this point. However, when the final point is place and the create process is finished it will correct itself and display the boundary fill correctly.

If a point is placed in the wrong location carry on laying the other points. When you have finished the create process you can then edit the boundary and 'Move', 'Delete' or 'Add' more points to the boundary. If the whole boundary is in the wrong location it can be moved as a whole from the right mouse click menu.

The types of boundary you can draw, which can be easily changed after creation if it is wrong, are:

Exclusion - The interior of the boundary will have a cross hatch pattern of the selected color. The type of boundary reported to other plugins, such as Watchdog, will be of type 'Exclusion'.
Inclusion - A user defined width cross hatch pattern will be drawn around the outside of the boundary in the selected color. The type of boundary reported to other plugins, such as Watchdog, will be of type 'Inclusion'.
Neither - The boundary will be drawn as a line with no interior or exterior fill. The type of boundary reported to other plugins, such as Watchdog, will be of type 'Neither'.

Please Note that these Types (exclusion, inclusion, neither) are Graphical only, and WatchDog does not use them in setting its internal alarms. We recommend that these graphic types be used appropriately to conform with the type of alarm that will be set from within WatchDog, however they will have NO EFFECT on the WD alarm type.

The type of boundary may change what other plugins do with the information, or how it is displayed. If using the Watchdog plugin and you set the boundary anchor watch the alarm will go off if you move outside of the boundary. If you are motoring/sailing and you have a proximity boundary watch set then the alarm will go off if you get closer than the specified distance. The first type of boundary should be an 'Inclusion' boundary and the second should be an 'Exclusion' boundary.

Note: A Boundary is a line joining two or more Boundary Points together. As such, each Boundary Point can have the same capabilities as individual Boundary Points.

Boundary Point

This allows the placing of individual points on the chart. They are very similar to 'Marks' that can be dropped by OpenCPN. However, they have the capability of being 'Exclusion', 'Inclusion' and 'Neither' boundary points. This is demonstrated when Range Rings are Displayed.

Exclusion - The interior of the boundary point, from the biggest range ring, will have a cross hatch pattern of the selected color. The type of boundary point reported to other plugins, such as Watchdog, will be of type 'Exclusion'.
Inclusion - A user defined width cross hatch pattern will be drawn around the outside of the largest range ring of the boundary point in the selected color. The type of boundary point reported to other plugins, such as Watchdog, will be of type 'Inclusion'.
Neither - The boundary range rings will be drawn as a line with no interior or exterior fill. The type of boundary point reported to other plugins, such as Watchdog, will be of type 'Neither'.

Boundary Points continue to be placed on the chart until the drawing create mode is terminated. This allows the placing of as many points with single mouse left clicks as the user wishes.

Text Point

This allows the placing of individual Text Points on the chart. They appear very similar to Boundary Points, but they allow the displaying of multi-line text in the desired font. They can have range rings, but these cannot be filled.

The text top left corner of the text is the reference point. There are 7 provided locations:

Top - which puts the text over the top of the point aligned to the left edge of the icon with the bottom just clear of the icon
Top center - which puts the text over the top of the point with the center of the text aligned to the center of the icon
Bottom - which puts the top edge just underneath the point aligned to the left edge of the icon. If you displace the point name the text should drop enough to show it
Bottom center - which puts the text underneath the point with the center of the text aligned to the center of the icon
center - which puts the text horizontal and vertical center over the icon.
Right - which puts the top edge aligned with the top of the icon, the left hand edge of the text just clear of the right hand side of the icon
Left - which puts the top edge aligned with the top of the icon, the text to the left of the icon with the right hand end of the text box just clear of the icon

The amount the box edge is offset is controlled by 8 settings in the opencpn ini/conf file. You will find them called:

DefaultTextTopOffsetX
DefaultTextTopOffsetY
DefaultTextBottomOffsetX
DefaultTextBottomOffsetY
DefaultTextRightOffsetX
DefaultTextRightOffsetY
DefaultTextLeftOffsetX
DefaultTextLeftOffsetY

These are not in any dialog box as they are very unlikely to be modified.

Changing the font in the properties box does not apply the font until the OK button is pressed on the properties box. The word 'Example' should change to show you the font selected. Changing the font in the properties box does not apply the font until the OK button is pressed on the properties box. The word 'Example' should change to show you the font selected.

When a Text Point is created the 'natural' scale at which it is created is stored. This is then used to determine what to show when scaling to larger scales. Currently at twice the natural scale the text gets hidden and at 8x the natural scale the text box gets hidden. This is currently hard coded.

To display text for the Text Point you will need to open the properties for the Text Point and fill in the 'Display Text' tab. This is simple text and does not allow individual formatting of different parts of the text. You can pick the font and the font metrics to use for all the text associated with one text point.

Electronic Bearing Line (EBL)

The EBL always starts attached to the boat with the far end of the line being placed by left clicking the chart. The default action for the end point is set in the main properties dialog. The end point can either be fixed to a Latitude and Longitude or move along with the boat. This allows the EBL to show the boat moving against a fixed point, i.e. passing a reef, or to show other objects moving relative to the boat, i.e. when the boat can tack to get around a bouy.

The EBL can be detached from the boat to allow placing of the start point where the user left clicks. The EBL can also then have the start point centerd on the boat but not move or re-attached to the boat.

Variable Range Markers (VRM’s) can be displayed as part of the EBL, by checking a box on the EBL properties (or set the default on the OD properties) and a range ring will be drawn based on the start point. If the end point of the EBL is moved the range ring will move with that point. This allows easily setting up of safety rings around a boat. The plugin provides additional information when moving the end point of an EBL/VRM

End Points A & B of an EBL can be in several states:
1. Associated with Boat position (boat lat long) - Moving with the boat.
2. Associated with a fixed position (lat long) - Not Moving with the boat.
3. When offset Point B is associated with Boat position (lat long) it moves relative to the boat position and stays at the same angle.

Right click selections for EBL are
1. When the EBL start point is attached to the boat… Pick a new start point.
2. When the EBL start point is not on the boat.. Center on moving boat or Center on Lat/Lon (not fixed to the boat)

This flexibilty is useful for Dead Reckoning to have “Fixed” EBL markers.

The default color is the same as for a 'Boundary Point' and it will draw 1 range ring. If you want to change that then you will need to get to the start point properties (double click the EBL and double click the first point), or if the first point is clearly visible, just go to its properties (right click the point and select properties) and you can change the number of rings, the colors. The rings cannot be filled.

The VRM colour, by default is set to the same as the default for a Boundary Point, but once you change the VRM color to be different from the Boundary Point default then it will stay this way, unless you select the match option in the right click menu.

There are two ways of changing the VRM color:

Under properties for the EBL with the VRM showing. Change the EBL color and the VRM color will also change.
Under properties for the EBL with the VRM showing get the properties of the 'boat'/'start' point and change the color.

It may seem strange at first to use an EBL to give you the VRM, but it makes selecting the VRM easier so that it can be dragged to the size required as there is a well defined point that can be selected. This is particularly true if you have many VRM’s at one time.

It is not necessary to loop through the preferences to enable the VRM for one EBL–the settings pop-up double clicking the EBL has all the necessary entries.

The popup for EBL’s contains both the forward and back bearing.

The main properties dialog in the general tab sets whether to use magnetic bearings or true. If magnetic is used then if you have the World Magnetic Model installed the variation will be used from that plugin. If not you will, currently, need to set 'UserMagVariation=0.00' in the ocpn_draw_pi section of the config file as there is no setting in the properties dialog for this.

Dead Reckoning (DR)

This draws a Dead Reckoning line with multiple points along it starting at the boats current location. As mentioned above, this tool does not use the mouse click to draw on the chart, rather it uses it to display a dialog box where the DR information can be entered. When the 'OK' button is clicked the DR will be created and drawn on the chart. At this point the line can be modified by changing the points that make it up. However, this may make the DR line not reflect what you expect as neither the time/distance between points is maintained, nor is the COG/SOG. So the DR line at that point becomes more of a line with possibly little meaning in the context of DR.

Guard Zone (GZ)

This draws a segment of a torus or doughnut. The centre is the boat and the angle and size is determined from the two points that are used to describe the GZ. When the GZ tool is selected the cursor will change to a pencil and a line will join it to the centre of the boat. When the left mouse button is clicked the first point of the GZ is dropped. Now when the mouse pointer is moved an angular segment of a torus is drawn, the size of which is determined based on where the mouse cursor is. The second point is dropped when the left mouse button is clicked. This completes the drawing of the GZ which will now be the default colour and filled in with a hatch of the default colour.

The GZ can rotate with the boat and be maintained with the heading or the coarse over ground. Or it can maintain its position relative to the boat irrespective of which direction the boat is moving. This is set in the default propertiesd but can also be changed for each individual GZ.

Parallel Index Line (PIL)

Annex to IMO res.A893(21)-Guidelines For Voyage Planning. Section 4- Appraisal

“Additional information which should be marked on the charts include: ….. Parallel index lines should also be drawn where appropriate.”

Annex to IMO res.A893(21)-Guidelines For Voyage Planning. Section 6- Monitoring, point (j)

“Radar can be used to advantage in monitoring the position of the vessel by the use of parallel indexing, which is a simple and most effective way of continuously monitoring that a vessel is maintaining its track in restricted coastal waters. Parallel indexing can be used in any situation where a radar-conspicuous navigation mark is available and it is practicable to monitor continuously the vessel’s position relative to such an object. It also serves as a valuable check on the vessel’s progress when using an electronic chart.”

This allows drawing a line which offset from a centre line by a specified amount. This offset line will move with the boat and can either rotate with the boat or stay at a specified angle. Drawing a PIL is the same as drawing an EBL. The index line only shows up when the centre line has been drawn.

Each PIL centre line can have multiple offset lines. To create more than the first line right click the centre PIL line and select 'Add Index Line'. A new index line will be drawn based on the default settings.

End Points A & B of an PIL can be in several states:
1. Associated with Boat position (boat lat long) - Moving with the boat.
2. Associated with a fixed position (lat long) - Not Moving with the boat.
3. When offset Point B is associated with Boat position (lat long) it moves relative to the boat position and stays at the same angle.

Right click selections for PILL are
1. When the EBL start point is attached to the boat… Pick a new start point.
2. When the EBL start point is not on the boat.. Center on moving boat or Center on Lat/Lon (not fixed to the boat)

The offset line has its own properties box which can be accessed by either right clicking the offset line or by double left clicking the offset line.

Each offset line can be moved using either left drag (if enabled) or right clicking the line and selecting move.

How to use PIL Good Parallel Index Line video link

How to plot for Collision Avoidance Collision Avoidance Plotting Part1 of 3

Properties dialogs

All objects that have been drawn have a properties dialog associated with them to allow changing of the objects attributes.

Boundary Properties

You can display the point properties by either double left mouse clicking on the particular line you want in the Points list or by right mouse clicking on the line, once it has been selected, and selecting 'Boundary Point Properties' from the popup menu. If you want to remove a particular point then left click the line to select it. Then right mouse click on the point and select 'Remove Selected' from the popup menu.

Boundary Point Properties

Basic

These are the properties for the selected Boundary Point. Any changes here will be made to the selected Boundary Point and, if the 'OK' button is clicked, will be preserved over a restart.

Extended

This allows you to stop displaying the Boundary Point on the screen and change the GUID if you want. You will need to click 'OK' to save the changes.

Text Point Properties

Basic

This tab controls the text that is displayed for the Text Point. Any changes here will be made to the selected Text Point and, if the 'OK' button is clicked, will be preserved over a restart.

Display Text

This tab is used to create and modify the text that will be displayed with the Text Point. It also allows the setting of values for an individual Text Point where as in the Preferences you settup the system wide settings.

Extended

This is the same as for a Boundary Point

Electronic Bearing Line (EBL) Properties

EBL Point

Basic

These are the properties for the selected EBL Point. Any changes here will be made to the selected EBL Point and, if the 'OK' button is clicked, will be preserved over a restart.

Extended

This is the same as for a Boundary Point.

DR Properties

DR Point Properties

Basic

These are the properties for the selected DR Point. Any changes here will be made to the selected DR Point and, if the 'OK' button is clicked, will be preserved over a restart.

Extended

This is the same as for a Boundary Point

Other

Copy and paste Lat/lon point

In any of the 'Point' property dialogs you can right click in either the Lat or Lon and get a drop down menu where you can select:

Copy
Copy Lat/Lon
Paste
Paste Lat/Lon

These will either copy/past in the selected box or will copy/paste both the Latitude and Longitude at the same time.

Settings

Options > Plugins > Ocpn Draw > Preferences
Under Preferences the Tabs are General, Boundary, Boundary Point, Text Point, Path, EBL, DR, DR Point, Guard Zone, Parallel Index Line, About and Help where various settings are selected. Generally the defaults should give a reasonable starting point. However, all the defaults that are used can be changed from here.

General

Confirm Object Delete

This setting determines whether a dialog box will be shown asking for conformation about deleting any objects. With it checked you will be asked to confirm all deletes, with it unchecked you will be able to delete any object without being asked for confirmation. If you do delete an object by mistake and you have 'Nav Object Backups' set to more than 0, you will be able to use one of those backups to restore your objects.

Remember properties dialog positions over restart

This setting saves the position of each dialog over a restart. If the user moves a dialog it will be in the same position when it is displayed after a restart. If this setting is not checked the default position, centre of the OCPN screen, will be used when the dialog is first displayed after a restart

Show Magnetic Bearings

If this is checked and there is a magnetic variation available then this will be applied to all angles that are used within the plugin. If it is checked and there is no magnetic variation available it will assume a '0' variation.

Allow Left Mouse Button Drag

This setting allows dragging objects by placing the mouse over the object, pressing and holding the left mouse button and dragging the object to the desired location.

If this setting is off you will need to right click on the object to get the popup menu and select move from that. Then you can press and hold the left mouse button and drag the object.

A word of warning from user Redog: If “Allow Left Mouse Button Drag” is checked it is very easy to move your entire boundary or zone to a new location, thus changing all coordinates of waypoints you may have painstakingly entered. If you only intend to move 1 waypoint leave unchecked and use right click and move waypoint. If you intend to move entire zone check this option, it is a brilliant concept and very useful.

Nav Object Backups

This setting determines how many backups to keep of the navigation objects file. The location of the files can be found in the opencpn.log file. Each time OpenCPN stops a new copy of the navigation obj file will be created. The latest file is called 'ODnavobj.xml'.

Edge Panning Sensitivity

This is the percentage of the screen size distance from the edge that will cause the screen to pan when using the drawing tools. The bigger this number the further from the edge of the screen your pointer will be when the screen starts panning.

Initial Edge Panning Sensitivity

This is the same as above, but is used after a drawing tool is picked but before the first object is created. This is supplied so that the screen does not start panning if you move your pointer off of the toll bar near the edge of the screen.

Display Toolbar

The plugin allows you to use two graphical methods of selecting the tool you wish to draw with:

The main Toolbar and the right mouse click
The Draw Toolbar

This setting determines if the tool bar is display and has three settings

Never - the toolbar is not displayed
Whilst Drawing - the toolbar is displayed whilst a drawing tool is active
Always - the toolbar will display all the time irrerspective of whether you are using the plugin.

Remove OCPN_Draw settings and restore to default on restart(No)

This setting allows the user to set all settings back to the default value. If the button has the label 'Yes' and it is clicked this will ensure that no settings are saved when OCPN is shut down. The text of the label will be changed to 'Remove OCPN_Draw setting and restore to default on restart (Yes)' to indicate what will happen. The button label will now say 'No' indicating what will hapen if it is clicked again.