|TIN Data Area Delineation Command
Delineates the interpolation zone (data area) for a TIN.
Works as a command in ArcMap and ArcScene. You specify the maximum edge
length for triangles that represent valid data. Triangles with edges
longer than this will be marked as nodata. Outside, or nodata, triangles
are not displayed in maps and scenes nor are they used in surface analysis.
This approach works pretty well when the data distribution forms a concave
boundary but no study area polygon is available to 'clip' the TIN with. It
helps to mark the long, skinny, triangles that tend to form around the
perimeter (to complete the TIN's convex hull) as NODATA. This type of tool
will tend to do most of the job but some touch up may be required. It's
therefore considered to provide a semi-automated solution.
How to use:
Add a TIN to a map or scene document. For this type of editing a map
is probably more efficient. The TIN should not have any previous
in/out classification performed by this command or through the use of
clip or erase polygons.
Execute the command and select the TIN in the resulting dialog's
By examining the data distribution (e.g. using the ArcMap Measure tool)
determine the maximum edge length for data triangles. For example, if
all data points are gathered at a distance of 20 units or closer
to each other than a maximum edge length of something a little larger
than 20 would be appropriate.
Specify the maximum edge length to use and press Apply. If you like what
you see press Save. If not enough triangles were removed enter a smaller
number and press Apply again. If too many triangles were removed press
Revert, enter a larger number, and try again.
There's an option to mark interpolation zone boundary edges as breaklines
when the TIN is saved. In most cases you want this to occur. Breaklines
serve to enforce the interpolation zone; preventing subsequent edits, such
as node deletion, from disturbing it.
The Data Area Delineation command's dialog is modeless. This state is
chosen so you can use other exploratory tools (e.g. zoom, pan, measure) while
being in the middle of the delineation process. You should not, however,
use tools that would be editing the same TIN as there would be a potential
Steps for compiling the DLL:
The VB code for this sample makes calls to one or more utility modules that are
shared by a number of 3D samples. The shared modules are located in the 'Utilities'
folder which is found directly below the main '3D Analyst' ArcObjects sample folder.
In order to compile the DLL make sure you have the latest version of the shared
A TIN that is not write protected in an ArcMap or ArcScene document.
||Implementation for TIN Data Area Delineation class.
||Most of the work for the command is done in this form.
ITinEdit, ITinAdvanced, ITinEdge