You may have seen our video demonstrating the GTWeb Client on an Android phone, but we have a new video showing off the app on a Motorola Xoom tablet which is running Android 3.0 (Honeycomb).
Our booth number is #1435 on the North-East side of the show floor.
GTI will have a booth at the TechAdvantage® 2011 Conference and Expo from March 8-11, 2011.
Our booth number is #1435 on the North-East side of the show floor.
We invite you to stop by and visit our booth. We will be showing the GTWeb Client for Android, GTViewer's Dynamic Graphics capabilities, GTField's Pole Joint Use application, Outage Analysis, Upstream/Downstream tracing, and much more.
GTVSendClose is a new utility that will be delivered with GTData. Running the new utility will gracefully shutdown GTViewer. You may think this is an odd utility to have, but it was requested by a customer who uses a very clever and effective means of distributing data updates to its GTViewer users. I will describe the process below and show how GTVSendClose helps out the process. It may be useful to your workflow as well.
First, a GTViewer dataset is created and placed on a USB Flash Drive along with any GTViewer product updates. An autorun.inf file is also included to run a script which copies the updates from the USB Flash Drive to the laptop. When the USB Flash Drive is plugged-in to the laptop, the update process automatically begins.
Second, once the USB drive is prepared, a USB Flash Drive Duplicator (like this one) is used to copy the flash drive to a number of other USB Flash Drive.
Third, the copied USB Flash Drives are disseminated to the users and they plug them into their laptops and the data is automatically updated, and the USB Flash Drive is returned.
One problem that occurred in this workflow was that the user could have left GTViewer running when the USB Flash Drive was plugged-in and the updates could not be copied because the data files would be locked by GTViewer. Not a terribly difficult problem to overcome (shut down GTViewer, and try again), but there is an improvement that can be made to the workflow.
By inserting a call to GTVSendClose (which can be located on the USB Flash Drive) into the update script launched by the autorun.inf, you can guarantee GTViewer will not be running when the update begins and eliminate the potential for locked files.
There are some caveats here. If a user has created a new session in GTViewer that has not yet been saved, GTViewer will prompt the user for a filename and wait for the user to respond which will interfere with the update. However, there are solutions to this problem as well such as using the External Session only option which will also use a default session name.
This article has two audiences:
Option Explicit On
Option Strict On
Imports System.IO
Public Class Form1
Private Sub StartButton_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles StartButton.Click
' a mechanism to loop through all the circuits...
For Each circuit As String In circuits
Try
filterId = filterId + 1
' build a list of vertices of the
' conductors for a circuit...
Dim pList As New List(Of Point)
pList = BuildPointList(circuit)
' find the start point (the one with minimal Y)
Dim startPoint As New Point
Dim pCount As Integer = pList.Count - 1
Dim yList(pCount) As Integer
For j As Integer = 0 To pCount
yList(j) = pList(j).Y
Next
Dim minY As Integer = yList.Min
' now find the index of the minimal point...
Dim i As Integer = 0
For i = 0 To pCount
If pList(i).Y = minY Then
startPoint = pList(i)
Exit For
End If
Next
' sort all points by polar coordinate
' against startpoint...
Dim sortedList As List(Of Point) = _
PreSortPoints(pList, startPoint, i)
' do the Graham Scan...
Dim convexList As New List(Of Point)
convexList = GrahamScan(sortedList)
Catch ex As Exception
'Logtime("Error in processing circuit " & circuit)
End Try
Application.DoEvents()
Next
End Sub
Private Function PreSortPoints(ByRef pList As List(Of Point), _
ByVal startPoint As Point, _
ByVal startPointIndex As Integer) _
As List(Of Point)
' start a new list and fill it with the
' start point, then all the points in pList '
' up to the startpoint, then
' all the points after the start point...
Dim sortedList As New List(Of Point)
sortedList.Add(startPoint)
For i As Integer = 0 To startPointIndex - 1
sortedList.Add(pList(i))
Next
For i As Integer = startPointIndex + 1 To pList.Count - 1
sortedList.Add(pList(i))
Next
' then sort the list by angle from zero,
' in preparation for the Graham Scan...
sortedList.Sort(1, sortedList.Count - 1, _
New FunctionComparer(Of Point)(Function(a, b) _
Orientation(sortedList(0), a, b)))
Return sortedList
End Function
' Does the point C lie counterclockwise or
' clockwise of the vector AB?
' If counterclockwise, return a positive number.
' If clockwise, return a negative number.
' If A, B, and C are colinear, return zero.
Private Function Orientation(ByVal A As Point, _
ByVal B As Point, _
ByVal C As Point) As Integer
Dim dif1 As Double = (B.X - A.X)
Dim dif2 As Double = (C.Y - A.Y)
Dim dif3 As Double = (C.X - A.X)
Dim dif4 As Double = (B.Y - A.Y)
Dim tmp As Double = (dif1 * dif2) - (dif3 * dif4)
If tmp < 0 Then
Return 1
ElseIf tmp > 0 Then
Return -1
Else
Return 0
End If
End Function
Private Function GrahamScan(ByVal slist As List(Of Point)) _
As List(Of Point)
Dim convexList As New List(Of Point)
If slist.Count < 4 Then
Return slist
Else
convexList.Add(slist(0))
convexList.Add(slist(1))
For j As Integer = 2 To slist.Count - 1
Do Until (convexList.Count < 2) OrElse _
Orientation(convexList(convexList.Count - 2), _
convexList(convexList.Count - 1), _
slist(j)) < 0
' i.e., if Orientation returns a
' number < 0 then remove the previous point
convexList.RemoveAt(convexList.Count - 1)
Loop
' in either case, add a point from slist...
convexList.Add(slist(j))
Next
Return convexList
End If
End Function
The VB.NET Project in a Zip File
Download here.
Discussion of the code
Practical results in GTViewer – What Problem is Solved?
This section is primarily intended for the audience of GTVx application developers.
We get questions from our users. If we are lucky. And if we are very lucky indeed, we get interesting questions. The application above rose from one: “Hey Charlie, is there any way to tell what streets are near a circuit?” “Probably, tell me more.” “Well, the dispatch department keeps a bunch of facts about each circuit. A map. The substation name. More stuff. And a list of the streets that are close to it. They look on a printed map and copy down the street names. Sure would be nice to do automatically.”
One of the most fortunate things that happens to GTVx application developers is that we can ask Joey Rogers how it would be most appropriate to approach a problem. In this case, he pointed me to the Graham Scan and a few web sites that describe it. And scanned a chapter of a textbook about the Graham Scan. From these, I was able to develop the code in the zip file. I think anyone who has worked for more than a few days with GTVx will recognize the techniques used in the project. Almost all of them come directly from code examples in the GTVx documentation.
Here’s a sketch of the approach: It’s pretty straightforward to use a query to get all the primary conductors on a circuit. Then it’s easy to get all their vertices. That is the point set processed by the two-step Graham Scan. Once you have an ordered list of points describing the convex hull, you can use that list to place a redline shape. Then you can count all the street features within the shape and use the CountDetails method to make a list of street names. Then you sort them and place them in a Listbox. Once all the circuits have been processed, you can write the Listbox contents to a text file. Done.
Not perfect. The convex hull surrounding a circuit may contain streets that are not very close to any conductor on that circuit. So the list of streets produced by the application is in practical terms a superset of street names from which inappropriate street names will need to be removed. I suspect this will turn out to be a manual task. But it makes producing the final lists of streets much simpler than starting with a map and a pencil.
Screen Shots
