Hi Russell, The application you are building sound very similar to what I am doing now.
Here is the information I have to work with; 1) a file consisting of two point lines representing flight lines 2) A text string on each flight indicating the frame start and frame end and and bunch of other info. I am using the densifer method mentioned in other posting. Here is what I did to get equal distance points along a line string. 1) All my flight lines were in a dgn file. Use Neighborfinder to find the text string closest to the flight line. The text string contained the roll number, frame start, frame end values, location, etc, etc, etc. 2) Separated the text string to get frame start and frame end. 3) calculated the number of frames for each flight line using expressionevaluator 4) calculated the length of the each flight line. 5) now with the frame count and flight line length you can calculate the distance between photo centers on each flight line. 6) Use Densifer and add vertices to each flight line based on distance between photo centers. USING THE DENSIFER WILL ONLY WORK IF YOU YOUR LINES HAVE ONLY A START POINT AND END POINT. 7) Use the chopper with VERTICE parameter set to 1. This will give you the photo centers as points. 8) now if you want to segment your original flight line you can use the pointonlineoverlay and this will "cut" your flight line to each photocenter. With your flight lines and photocenters, you can start creating your photo foot prints if you want with the 2D box replacer and the rotater transformer. Ken --- In [email protected], "Russell MILLER" <[EMAIL PROTECTED]> wrote: > > Dale, timely response, I've been at this all day and making progress. > > > > Setting some terminology and history might be useful here. This is an > aerial photogrammetric application. It's easy to picture an aircraft > flying back and forth creating "runs" and shooting photos along the way. > The points are the centres of the photos, the lines are the flight runs. > The reason we have this problem is because we are working with old > photography going back to the 2nd WW when airborne DGPS did not exist, > so in order to make spatial data sets we have to create the meta data > for each point (photo). > > > > I could not make the densifier work so have moved on to the > labeller/coercer route. I have successfully calculated the interval by > calculating the length along a line connecting the points and dividing > by the Last Point number less the First Point number less 1. > > Interval = ((Last Point number - First Point number)-1) > > > > Once that is done I then produce, as you suggested, labels with > "interval" and offset to zero. Using Coercer to change to point geometry > it's all good at this point. > > > > The next step is causing problems. That is renaming the newly created > points to their true number. The labeller assigns whatever attribute I > give it so they all come out the same. I need to create procedure that > checks the First Point adds "1" to it, creates a new attribute for that > point, moves to the next point adds "1" to the previous point, creates a > new attribute and goes through the line of related points. When the > points on the line are done, the next line of points is started and the > procedure continues through the data set. Then I could remove/rename > attributes to suit. > > > > You can see what we are trying to accomplish by going to: > > > > http://www.ntlis.nt.gov.au/imfPublic/airPhotoimf.jsp > > > > Thanks again, > > > > Russell > > > > > > ________________________________ > > From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Dale > Lutz > Sent: Thursday, 28 September 2006 2:29 PM > To: [email protected] > Subject: Re: [fme] Creating intermediate points along a line > > > > Hi Russell, > > I'm not quite sure I understand how the interval should vary for you. > Is it a function of the length -- perhaps if you can provide more > details on how you'd like the interval calculated we can give some > input. > > Its an interesting application indeed. Perhaps the labeller may be > what you need rather than the densifier, let us know if you run into > difficulties. > > Dale > > On 9/26/06, nichols2bdarwindpi <[EMAIL PROTECTED] > <mailto:Russell.Miller%40nt.gov.au> > wrote: > > > > Thanks for ideas on creating the points along a line. One more thing > > to consider. I have 1oo's maybe a 1000 of these to do and need to > > automate the interval calculation. The points are numbered in > > sequence along the line so the total number of points I need to add > is > > =(the last point number - the first point number)-1. I'm attempting > to > > use ExpressionEvaluator to do the calculation but can't figure out > the > > expression. > > > > This represents aerial photography flight lines. The first photo > taken > > is given a number and the rest follow in sequence. I have been given > > the first and last frame of each "run" and need to calculate the > > frames along the run. > > > > Thanks for helping out with this. > Yahoo! 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