Tutorial 7 - Symbols
In this Tutorial
you will learn
¨
the
definition of a Symbol
¨
the concept
of Symbol size
¨
the concepts
of Representative and Pictorial Symbols
¨
Inserting Symbols manually - in space and over
points
¨
Inserting Symbols using
Feature Codes
¨
Inserting a “Pictorial Symbol”
¨
How to insert Descriptive Text into a Job.
What Are Symbols?
Symbols are
standard “drawings’ that can be inserted into any Ezicad job.
Any drawing that
is stored in Windows Enhanced Metafile Format (EMF) can be used as a symbol
within Ezicad. Note that images stored in Adobe Placeable Metafiles (*.apm) and
Windows Metafiles (*.wmf) can also be used.
The EMF Format is
one commonly used by Windows programs to store vector based images i.e. images
which are composed mainly of lines, circles and the like.
Most Windows
based CAD packages (e.g. Autocad, AutocadLT, QuickCad, TurboCAD) can store or
export drawings to an EMF/WMF file, as can other graphics or drawing packages
such as Windows Draw, Corel Draw, Adobe Illustrator, PaintShop Pro.
In addition to
the CAD or Draw type packages, there are a variety of other commercial packages
available either on the WEB, or at your local computer store for very little
money which will create Metafiles for you.
For example,
there is a program called Metafile Companion published by Companion Software
which is available from their Web site at www.CompanionSoftware.com which you
can try 30 times before you register for around $US30.
How do you Create a Symbol?
How you create
any particular symbol is determined by the package which you choose to use, and
you should refer to the instruction or help files which came with that package.
There is the
capability to export a symbol from within Ezicad, - see File > Export EMF (Symbol). We warn you that it provides
only a very basic functionality, and exports any strings which you have in a
job to form a symbol. If you are creative, you can use it to construct a wide
variety of symbols, but we would advise you that a small investment in another
specialised program will soon be repaid in terms of time saved.
Before you ask,
we have no intention of doing any more work on routines to create symbols,
because to do so would be a prime example of re-inventing the wheel. Even if we
wanted to, we couldn’t hope to match the features available in programs like
Metafile Companion even at ten times the price.
We can however
supply you with a program that will convert any symbols you created with
previous versions of Ezicad into metafiles if you request it.
Some Basic Concepts
Before you go any
further, it is important that you comprehend a couple of simple facts about
these symbols you are going to use.
The Size of a Symbol.
First you need to
be aware that symbols can be of various sizes, depending on which package was
used to create them, and since “computing”
and “standards” are mutually
exclusive, there is no such thing as a standard EMF/WMF, even though the
standard itself is reasonably well defined.
For example, if
are using WMF, and you create a simple circle in package A it might have a
diameter of 1 metre, or 1 foot, but if you create the same thing with package B
it might have a diameter of 1 yard or 1 mile, but when each of them creates a
WMF, you end up with a circle with a diameter of 1.
If you are using
EMF files, the relative size should be stored in the file, but there is no
guarantee that the author of the package that created the file went to the
trouble to implement the entire standard.
To attempt to
bring order to some of the chaos that can ensue from differing sizes, Ezicad
takes any symbol you provide and scales it to fit into a square with sides of 1
metre in real world coordinates.
So, any symbol
which we provide, or which you get from a library somewhere, or which you
create yourself will end up sized to fit into a rectangular box. By default,
this box is a square with 1 metre sides, but you can use the Width and Height
parameters to make it the rectangle of the size you need.
Sizing Symbols
From the basic 1 metre square, you can then apply size factors for Width
and /or Height as you insert the symbol into the job so that it appears the
correct size on the screen and on the plans you create.
For example, if
you take the circle we mentioned above and inserted it directly into a job it
would end up with a diameter of 1 metre.
However, if you
needed it to represent a drain hole with a measured diameter of 600mm, you
would need to assign a size factor of 0.6 for both Width and Height as you
inserted it into the job.
Similarly, if you
wished the circle to represent a pit with a diameter of 1.5 metres you would
need to use a size factor of 1.5 for both width and height when you inserted
the symbol into the job.
This initial
sizing as you insert the symbol will result in the symbol being drawn at the
correct size in relation to other features in the job.
If the symbol you
were using was a rectangular pit which measured 0.7 by 0.4 on the ground, then
you would take the symbol you wished to use and apply a Width of 0.7 and a
Height of 0.4 to achieve the correct result.
Scaling Symbols
As well as
determining the size of the symbol in real world dimensions, you also need to
determine if a particular symbol will be scaled to match the drawing scale when
the job is plotted out.
Symbols can
either be considered as representative or pictorial.
For example, the
drainage pits mentioned above, would normally be representative i.e you would
like them to be drawn at the correct scale on the plan to represent their true relative
size on the ground.
Alternatively,
there are things such as light poles, or traffic lights or survey permanent
marks which you may wish to represent with a symbol which is purely pictorial
i.e. it represents the location and identity of the feature, but does not
necessarily represent its true size in relation to other features on the plan.
For example, the
survey mark that we mentioned might be a nail in a kerb. If this nail was 10millimetres across the
top, and you tried to represent it at the correct size on a 1:1000 drawing you
would not see it, so it would be far more sensible to make its symbol
non-scaleable so that it holds the same size regardless of the scale of the
drawing.
So, armed with
these basic concepts it is time for you to try and apply them in a vaguely real
situation, and to show you the procedure we will use some of the sample symbols
supplied with Ezicad.
Using
the Symbols Supplied.
We have provided a number of simple
symbols with Ezicad to get you started, and we will concentrate on using just a
few of these to show you the process of getting symbols into your Ezicad jobs
and onto your plans, which is the ultimate aim of the exercise.
Start Ezicad and
use File Open to open up a job called symbols.CDSdb in your Tutor folder. Once
the Job opens, maximise the screen.
In this job you
will see there are 12 points on the screen arranged in a rectangular fashion as
seen in the screen at left.
Pull down the
Entry menu, select Symbols, followed by Symbol Library, and the screen will
appear as seen below.
Here you will see
all the symbols that are currently stored in the Variable folder displayed for
you, and you may scroll down using the scroll bar on the right hand side to see
all of them.
If you look at the columns for a moment,
you will see a graphic picture, the name of the symbol, a check box under the
heading scaled, the Width and Height to be used and columns for Insert X and
Insert Y.
If the symbol is
to be representational, and change scale with the scale of the drawing it is to
be plotted on, then the “Scaled” box must remain checked. Logically then, if you want to represent a
particular symbol as pictorial only you would uncheck the Scaled Box.
The Width and
Height columns default to 1 as mentioned above for all of the default symbols
supplied, and you can size each symbol individually as it is inserted into the
job.
Alternatively,
you can create symbols that are already sized if this suits your type of work.
For example, say you did detail surveys which involved picking up a large
number of standard drainage pits, and you knew that they only came in diameters
of 300, 600 and 1200 millimetres.
If you have a
base symbol called Pit that was a circle with a base diameter of 1 metre, you
might like to create three copies of the symbol Pit called Pit3, Pit6 and Pit12
respectively.
You could then
enter width and heights of 0.3 for Pit 3, 0.6 for Pit 6, 0.9 for Pit9 and 1.2
for Pit12, and then instruct the field party to code the points accordingly.
The shift columns
allow you to offset a symbol from the point over which you insert it, and we
will cover this facility in a later tutorial, once we have mastered the basics.
If you scrolled
down through the symbols, you would have seen that there were a number of TREE
symbols, and we will first use a couple of these to demonstrate how the symbol
can be inserted both manually, and automatically by means of the Code Library.
Inserting
a Symbol Manually
First off we wish
to insert a symbol called TREE1.
Pull down the
Entry menu, highlight Symbols, and select Insert a Symbol and the screen will
appear as seen below.
You can use the pull down option and
scroll down through he symbol names, or you can type in TREE1.EMF in the field.
Once you have
TREE1.EMF in the field select the OK
button and you will see the pop up screen disappear, and a square will appear
attached to your cursor.
Move your cursor
and you will see the square will follow you, and you should position the tip of
the cursor over point 9 as seen in the screen below.
Once you have
positioned it correctly, simply press the left button on your mouse, and the
square will be placed centrally over Point 9.
Now, at this
stage you are probably thinking that you have been robbed, since the square is
hardly a tree 
symbol.
Don’t be
concerned. For reasons of speed, only
the surrounding rectangle is shown when you are placing the symbol.
If you redraw the
screen by pressing the “D’” key, the symbol should appear. If it does not, you need to make sure symbols
are turned On using the Modes screen.
So, either press
the F9 button, or use the Modes Icon to bring up the Modes screen. Make sure
that you check the On button on Symbols which is on the bottom right of the
screen, and then select OK.
When the screen
reappears, you will see the rough outline of a tree appears in place of the
square, and you may zoom in to get a closer look if you wish.
OK, you have a
symbol in place, but because you didn’t do anything about the scaling when you
inserted it, your tree will appear with a canopy of 1 metre across, which means
it is probably closer to a shrub rather than a tree.
Lets now insert
the same symbol over Point 10, but this time our field party has told us that
the canopy of the tree has a spread of 5 metres.
Pull down Entry
again, highlight Symbols and Select Insert a Symbol.
Enter TREE1 as
the symbol to insert, and this time enter a scale of 5.
You will see a
bigger box (5 times bigger in fact) than you saw last time, and you should
insert it on Point 10.
Again the square will be shown, but when
you next redraw the screen you will find the screen at left, with a tree with
spread of 1 metre over point 9 and a tree with spread of 5 metres over point
10.
Now, if you look
closely at Point 10 (maybe even zoom a window around it if you like), you will
see that the dot representing the point, and the dot marking the centre of the
tree do not coincide.
This is because
we simply positioned the cursor “roughly” near the point, and in some cases
this is more than good enough.
However, in other
cases you require the symbol to be locked onto the point precisely, and you can
achieve this as follows.
Locking
the symbol over a point
Pull down the
Entry Menu, select Symbols and then select Symbol Display to see a screen like
that below.
If you look down
the column headed “Point” you will find that both symbols show –1. This
indicates that the symbol has been placed “in space” rather than exactly over a
point in the database.
If you look to
the columns to the left you will see the coordinates that have been used to
located the point when you positioned it on the screen.
You can use this
capability to position all manner of descriptive information that is not
related to any particular point on your job.
For example a
North Point can be located wherever you like, as can your Company Logo if you
have it in WMF format.
When you wish to
position a symbol exactly over a point, you simply type the point number
required into the Point Column, so type in point number 10 and click OK to save
the change. If you now look closely you will see that the point and the centre
o the tree symbol correspond.
(You will see
later in this Tutorial that you can also use Feature Codes to position symbols
over points)
NOTE: you may, if
you wish, come directly to this table and simply type in the name of the
symbol, the size and the point to locate it over if you wish to manually
position symbols over existing database points.
You can also use
this table to alter the sizing of a symbol you have already placed.
Delete a
Symbol
In the event that
you wish to delete a symbol that you have placed, you also come directly to
this option.
Use your cursor
to select the Line Number of the symbol you wish to delete. I.e. click on the
line number on the left-hand side.
You will see the
entire line is highlighted or selected, and you can then simply press the
Delete key to remove the particular symbol.
Be careful, since
there is no undo facility available.
Next it is time
to learn how to use feature codes to insert symbols automatically.
Insert a Symbol using the Code Library.
As well as
inserting individual symbols as we have already done, you can ‘automate’ the
process by using codes and the code library if you wish..
To do this, it is
necessary for the points to be coded with ‘feature codes’ and for you to set up
a code library defining what you wish to do with those codes.
In Job ‘symbols’,
we have already supplied codes for points 3 and 5, and you can check on these
codes by either using Modes - Display to turn them on, or by using the “?” key
to query the points. (You should find that Point 3 has a code of PP to indicate
a power pole, and Point 5 has a code of STN to indicate a Station.)
So, we have
complied with the first of the requirements in that we have some points with
codes.
Now we need to
set up a code library.
Pull down the
Entry Menu, and select Feature Codes.
The screen should
appear as below.
We wish to create
a new library, and we will give it a name of SYMBOLS, so type that into the
field titled ‘Library Name’, and then press the TAB key to move on to the next
field which is titled Tag.
This is the
character that you will use to indicate that you wish to ‘Tag” codes together,
and though it is not applicable in this example, you should enter in the “+”
key, and then press the Tab key to move to the field titled ‘Attribute’.
Here enter the
‘-‘ character, since later in this example we will wish to apply attributes to
the symbols we are using.
The cursor will
now be in the Column titled Code on the first line, waiting for you to type in
the feature code you have used, and then to indicate what you want done with
it.
Our first code is
PP, so type it in and press the Tab key to move into the Layer column. Type in ‘Power’ to indicate
that all points with this particular code are to be assigned to a layer called
power.
We are not
interested in stringing the points together for the moment, so you can ignore
the columns titled String, Folder, Colour, Linetype, Break and Tree simply
‘click’ in the ‘Symbol’ column.
The ‘Symbol
Details’ window will appear, and you can use the scroll facility to search
through the available symbols until you find the name ‘POWPOL’.
Select it and
choose OK to indicate that wherever the program finds a point with a code of PP
it is to insert the symbol ‘powpol’.
Now ‘click’ on
the next line in the ‘code column’ and type in the code of STN.
Assign a layer
called ‘Marks’ and then click in the symbol column and scroll down until you
find ‘stn.emf’, and select it
At this point you
are ready to now apply the codes to the points in the database, so select the
‘Apply to DB’ button.
A prompt will
appear to inform you that the library has been applied, so click on OK to
confirm the message and proceed.
Then select the
OK option to save the code library details and close down the window.
You screen will
appear as seen at left, and you can see that the relevant symbols have been
automatically inserted.
Now, before you
get carried away with the excitement of this discovery, you need to consider
the size of these symbols.
You will see that
they are both approximately the same size as the tree which is over point 9,
which we have already determined is 1 metre across.
Since most power
poles are only about 300 to 400 millimetres in diameter, we obviously need to
make an alteration here.
Also, most Survey
Stations are marked with a peg or monument that is considerably smaller than 1
metre square, so we need to take remedial action here as well.
Sizing
Symbols with the Code Library
You already know
from your tree exploits that you can change the size of a symbol within the
symbol library itself, and now you will see another method for achieving the
same result.
In this instance,
power poles can be of differing sizes, so we don’t wish to use the symbol
library to reduce our symbol to a uniform size.
Instead, you need
to size the symbols as they are inserted and you can achieve this as follows.
Pull down the
Entry menu and Select Feature Codes.
Use the pull down
arrow and select a Library name of SYMBOLS, and you should see your code
library again.
Move the cursor
into the Action column on the first line, and position the cursor at the end of
the entry.
What you wish to
achieve here is to have a power pole drawn with a diameter of 300 mm. To
achieve this, you need to Magnify or
Multiply the base scale of 1 metre by a factor of 0.3.
So, after the
word ‘powpol’ you place the ‘-‘ sign to indicate to the program that attributes
are following.
The attribute in
thus case is ‘M0.3’.
Your entry should
now read ‘S=POWPOL-M0.3’
Next select the
“Apply to DB” option.
When you redraw
your screen with any of the zoom or pan functions, you will see that the symbol
representing the power Pole has now been reduced in size so that it appears
correct in relationship to the tree over Point 9 that you compared it to
before.
Representing
Pictorial Symbols
If you recall the
basic concepts at the start of this tutorial,
you will remember that we said that a pictorial symbol is one which is
inserted at a particular size which is generally not representative of its size
on the ground, and that it is generally not scaled up and down with the scale
of the final plot.
The symbol signifying
the Station which is inserted over Point 5 is a case in point.
Here the Station
is in fact a Peg which is 50 millimetres square, but if we tried to draw the
symbol to that particular size we would have difficulty finding it.
The size you
choose will depend largely on the scale of the drawings you are going to
produce, and to your particular aesthetic values, so please treat the number
used below as a guide only, and use your own values as you see fit.
For example, if
you normally produced drawings at a scales of 1:500 and 1:1000, you would
probably need to have your station symbol plotted at about 4 millimetres on the
plan, (rather than the 0.5 millimetres at 1:1000 if you left it as
representative.)
You also wish to
indicate that this symbol is NOT to be scaled with the plan scale, but will be
drawn at 4 millimetres regardless of the scale of the plan.
To achieve this,
pull down the Entry Menu, select the Symbols option and then select the Symbol
Library option.
Scroll down until
you find the “STN” symbol.
First, ‘uncheck’
the scale box to indicate that it is to stay the same size regardless.
Then enter a
“Size” of 4. Why 4 I hear you ask?
Because, you set
the symbol up as if it were going to be plotted on a 1:1000 plan.
If that were the
case, and you left it at 1, the square with 1 metre sides holding your symbol
would be plotted on the paper with sides of 1 millimetre, whereas you want them
to be 4 millimetres.
If you need to insert Descriptive text
into the job for things such as Road Names or construction notes or Tree
descriptions, you can do so in the following manner.
Pull down the
Entry menu, select Text, and then select Insert Text.
The screen
will appear as at left.
You will see a
window pop up, and you can “Drag” it
around the screen so it is clear of where you want the text to be.
You can type
in whatever text you wish to add in the ‘window’ at the top of the pop-up.
Here we wish
to type in a description of “Oak Tree 12 m high” to the right of the tree over
point 10. So first type the string of text into the text window.
You can now
choose where to locate this text, and you may either Point with your cursor to
indicate where it is to start, or, if you wish you can type in the coordinates
of the start point you require.
In most cases
pointing will be simpler, so move your cursor to a location at the right of the
tree. Pick the point with your left mouse button, and you will see the
coordinates appear in the Text entry box.
Next you need
to enter in the bearing for the text.
You may either type in a bearing in the usual format, or you can use the
“P” option to get the bearing between two points, or you can use the ‘D’ option
to draw the bearing you require on the screen
In this case,
we will use a bearing of 45, so type that in.
You now can
enter in the layer name to store the text on, and in this case ‘text’ will be
adequate
Next you need
to set the font and size for the characters, so pick the ‘button’ labelled
‘Font’.
You will see
the familiar windows font selection panel appear to allow you to choose what
you require.
As an example,
pick Arial, 10 Point Regular and then select OK.
You will see
these values now appear in your pop-up text window similar to what you can see
in the screen at right.
Once you are
happy, press the OK button and the pop up screen will disappear.
Now, before
you panic because you can’t see the words let me assure you that the text will
appear the next time you redraw the screen.
If you don’t
wish to take my word for it, press the ‘D’ key to reDraw, and you should now
see the words, as seen below.
Armed with this knowledge, you can now
insert all manner of text onto your drawings, but I do advise that if you wish
to get into serious schedules, and tables of text and the like you are much
better advised to do it in your CAD package.