Create TIN (Delauney triangulation)
line : GT_TRIANGULATE
The GT_TRIANGULATE command connects a set of points to form irregular triangles based on the TIN model.
Annotate chainages along a route
The GT_CHAINAGE command is
used to annotate chainage distances along a traverse. The traverse must be drawn
as a 3d or 2d polyline.
The annotation is done using
a default tick block (named TICK-n) or a user-defined block. The What to
annotate section determines the points along the traverse where the
annotation is done. You can create annotations in several ways - either at each
vertex of the polyline (Source) or at a fixed regular distance (Interpolate)
along polyline, both Source and Interpolate or at picked points
locations along the traverse. Please be aware that picked points annotation are
always slope measurements and not horizontally projected ones irrespective of
the settings shown in Measure Distances in.
Annotation can be done using
chainage value or route name. Depending on the selection, the tick mark block
will display the route name or the chainage value as its attribute.
Gap Length: This is the distance between the end of the annotation tick mark
and the annotation text.
Starting Chainage Count: When the Annotate Using is set as Route
Name, the Starting Chainage Count defines the running number count of
the first chainage point.
Chainage Format: This drop down box allows to select either 0+00, 0+000
If 0+00 is selected, the distance of 100 drawing units is written as 1+00 and
1000 feet is written as 10+00..
If 0+000 is selected, the distance of 1000 drawing units is written as 1+000 and
100 feet will be 0+100.
Choose the format that most closely suits your annotation style.
Chainage Description Options:
You can import and display additional chainage descriptions (at specified
changes) from an external ASCII file. This file must be a comma delimited ASCII
text file in the following format:
187.0,FILL EXISTING SWALE
246.75,T/S 14"PINE LT
278.5,EXIST WB,INSTALL DIP
398.0,END AB PLACEMENT
465.5,T/S 2-SNAGS LT
530.0,T/S 12"PINE LT
553.0,EXIST WB,INSTALL DIP
612.0,T/S 12"PINE LT
854.0,T/S 16"SNAG LT
895.5,T/S 12"SNAG RT
923.0,EXIST WB,INSTALL DIP
978.5,T/S 14"PINE RT
1033.0,T/S 14"SNAG LT
The first field is the chainage value followed by the descriptions for that
chainage, separated by comma(s). More than one description can be specified here
separated by commas.
The operating parameters of this command can be saved into ASCII INI files and
Draw cross-sectional profile from 3D polyline
The GT_PROFILE command
is used to create cross-sectional (longitudinal) profiles from 3d polylines. The
elevation values (heights) are displayed along the Y axis while the chainages
(distances) are displayed along the X axis. In addition, there are options to
create named sections, segmental distance annotation, X and Y coordinates
annotation as well.
The What to annotate section determines the points along the 3d polyline
where the profile annotation is done. You can create annotations in several ways
- either at each vertex of the polyline (Source) or at a fixed regular
distance (Interpolate) along polyline, or both Source and Interpolate.
Factor: This is the
ratio of the vertical to horizontal scale of the profile. This value shows how
many times the vertical measurements (heights) are exaggerated relative to the
horizontal measurements (chainages). The horizontal measurements are always
created at unit scale (1.0).
Profile Interval: Denotes the interval distance at which the 3d polyline
is profiled (this affects the smoothness of the profile curve).
Annotation Interval: Denotes the interval (distance) at
which the profile annotation is created.
Reference Height: This is the elevation at the base of the profile.
Specifying a non-zero value will prevent the profile vertical lines from being
Starting Chainage Count: When the Create Named Section option is
selected, the Starting Chainage Count defines the count of the first
point being annotated.
Adjust Annotation Spacing: If the points being profiled are too close to
each other, the annotations fall over each other and are cluttered
(un-readable). If this option is checked, the annotations will be spaced out
(and connected with a guide line) so that the annotation text will not overlap.
enables special annotations to be placed at positions along the 3d polyline
where other objects cross. The crossing objects supported are blocks and
shapes. i.e if there is a block or shape object anywhere along the line, that
position within the profile will also be annotated.
The Distances from
profile bottom option define the distance (drawing units) from the bottom of
the profile line to each one of the different horizontal annotations.
Quick stats: Produces
statistics about the polyline being profiled. The values obtained from the
polyline statistics provide valuable guidance to set the profile parameters more
Adjust cross-section elevations
line : GT_ADJUSTLEVELS
GT_ADJUSTLEVELS command is a “fixer” command to re-compute cross-sectional
profile elevations. Often, surveyors may need to re-compute or modify the
profile elevations from a new set of elevation data or new profile obtained from
other sources. Rather than having to re-create the profile from a new 3d
polyline, this command helps by regenerating the levels (elevations) by picking
the modified (or new super-imposed) cross-sectional profile line. In other
words, while the GT_PROFILE command creates a cross-sectional profile (and
elevation / chainage annotations) from a 3d polyline, the GT_ADJUSTLEVELS
command would take an ‘already-created’ profile as input and re-create the
elevations and chainages.
A few basic parameters that this command would require are datum (reference)
height, datum point location, horizontal / vertical exaggeration factors and
annotation interval, all of which are asked on the command-line.
Draw graded polylines
The GT_DRAWGRADE command creates graded 3D polylines
or lines. The grade (or slope) can be specified in several ways, as a percentage
(%), decimal (1:n) or as degrees. The grade can be created as a 3d line/polyline
or even as descriptive leader objects (with arrows-heads).
Note: Use DIMSCALE variable to control leader arrow size.
Perform adjustment of traverse closing errors
The GT_TRAVADJ command implements the Bowditch's method of traverse adjustment for both
open and closed traverse polylines. The Bowditch's method is based on distributing the linear mis-closure (closing error) across each vertex proportionally
as a ratio bewteen the distance from the start to the total traverse distance.
Toolbar : Civil
display of TIN triangles
The GT_SLOPEDISPLAY command is used to color-code TIN triangles (3dfaces or 3dpolylines) as per a range of slope values. A maximum of 5 slope ranges is allowed. The start and end slope values of the range is specified and a color is chosen for each slope range. The slope representation can be done as a solid HATCH fill or a SOLID object fill.
Create and place map sheet index block
line : GT_SHEETINS
GT_SHEETINS command allows to insert a sheet-index (a block which is rectangular
in shape and shows the boundary of a plotted sheet) on a map by specifying the
required size of sheet in X (horizontal) and Y (Vertical) direction with
specified rotation angle. The block carries a single attribute which also stores
the sheet name.
Create map grid
line : GT_ANNOGRID
The GT_ANNOGRID command is
used to draw a map grid within a map sheet. The map sheet can be specified
either by picking an existing sheet index block (created by the GT_SHEETINS
command) or by picking points on the screen to 'show' the extents of the map
sheet. Two types of annotation parameters are required – the X/Y spacing for
the grid tick marks and the X/Y spacing for the grid annotation text at the
edges. The grid tick marks as well as the annotation text are defined in
pre-defined blocks which can be customized to achieve a custom grid. A sample
format of these pre-defined blocks is provided in the BLOCKS
folder under the GeoTools installation folder. The name of the grid tick mark
block is GRID_CROSS.dwg and the names of the grid text blocks (annotations at
the edges) are TICK_LEFT.dwg, TICK_RIGHT.dwg, TICK_TOP.dwg and TICK_BOTTOM.dwg.
You CAN CHANGE the style/color/linetype etc of these blocks to suit your
annotation style and requirements but DO NOT change the insertion point
or the attribute tag of the lone attribute in this block.
scale value used here is only as a key to specify at which map scale the mapping
is done, so that all the grid annotation settings can be saved for future
reference with this as the reference. (Note: This scale has no effect on any of
the other values specified in the grid annotation settings).
You can thus define multiple
sets of annotation settings for different map scales and display them in the
list box. Such sets can be saved and restored from ASCII INI files for future
use. You can then choose one of them and click on Make Current to make
them the current settings. Upon clicking on Ok, the current settings are used by
the program to perform grid annotation.
Compute volumes across multiple cross-sections
line : GT_CROSSSECT
The GT_CROSSSECT command is a multi-process command that uses several existing GeoTools commands like GT_DRAPEPOLY, GT_SET_Z_PL and GT_PROFILE to perform a series of operations intented to facilitate volume computations across a surface.
The idea behind the GT_CROSSSECT command is to create cross-sectional profiles across the terrain at regular intervals (strips) and to compute the cross-sectional area formed by each strip. This area multiplied by the width of the strip gives the volume of each strip of the terrain. The sum of the volumes of each strip gives the volume of the entire surface.
Bearing and Distance
line : GT_BEARINGDIST
The GT_BEARINGDIST command will create the bearing angle and distance annotation (as text objects) from one selected point to another.
Round off bearings
line : GT_BRGROUND
The GT_BRGROUND command is used to round off bearings to a specified precision. Usually the bearings are represented in typical styles like : 50-23-24, 149d49'32", 38° 55' 46", N 149° 41' 27" E, S 85d27' E and so on. The GT_BRGROUND command works on the seconds part of the bearing and rounds it off to the nearest number of specified seconds.