Any Surveyors?

[CosmicTruth]

If there are any surveyors active here let me know. Hopefully 50G users who like to trade ideas and program code.

[MNH]

I'm an active surveyor. I use the HP 50g as a backup for my HP 48GX. I program both calculators with UserRPL. I wouldn't mind trading ideas and program code.

[Jacob Wall]

I am both a surveyor and a hobby developer of software for the HP 50g. I visit this forum fairly frequently although I don't post very often. My main area of expertise within the 50g realm is System RPL programming but as may be expected I am quite familiar with User RPL as that was the first stepping stone into the platform. I have written quite a bit of software for this machine as is evident on my website, and I would be happy to trade ideas or offer input on any 50g related programming, especially related to surveying.

Jacob

[CosmicTruth]

(06-11-2014 03:33 AM)MNH Wrote:  I'm an active surveyor. I use the HP 50g as a backup for my HP 48GX. I program both calculators with UserRPL. I wouldn't mind trading ideas and program code.

(06-14-2014 01:29 AM)Jacob Wall Wrote:  I am both a surveyor and a hobby developer of software for the HP 50g. I visit this forum fairly frequently although I don't post very often. My main area of expertise within the 50g realm is System RPL programming but as may be expected I am quite familiar with User RPL as that was the first stepping stone into the platform. I have written quite a bit of software for this machine as is evident on my website, and I would be happy to trade ideas or offer input on any 50g related programming, especially related to surveying.

Jacob

Welcome to the 50G surveyors association . I would like to see your website sometime. I don't actively do the System RPL, just the User RPL. I have a {choose:good/bad} habit of making a little utility program for anything I do more than a couple of times, so I don't know if i'm a hobbyist or a fanatic or just crazy. I'm getting to the point that I don't like to run programs like libraries or 'code' because I enjoy seeing the program RPL code and trying to learn how it works more than just getting the benefits of having a program do something for me.

have fun ttyl

[Jacob Wall]

Quote:Welcome to the 50G surveyors association .

Nice, too bad the 50g had to near end of life to start a surveyor's association, LOL

Quote: I would like to see your website sometime. I don't actively do the System RPL, just the User RPL. I have a {choose:good/bad} habit of making a little utility program for anything I do more than a couple of times, so I don't know if i'm a hobbyist or a fanatic or just crazy. I'm getting to the point that I don't like to run programs like libraries or 'code' because I enjoy seeing the program RPL code and trying to learn how it works more than just getting the benefits of having a program do something for me.

Sounds like we got into programming for similar reasons, I sent you a PM

[rprosperi]

(06-14-2014 01:29 AM)Jacob Wall Wrote:  I have written quite a bit of software for this machine as is evident on my website, and I would be happy to trade ideas or offer input on any 50g related programming, especially related to surveying.

Jacob

Thanks for introduction, you're certainly in the right place! You'll find you get more out of it, and have more fun, by posting and contributing.

Please share a link to your website - and I predict you will see a definite surge in bandwidth usage in the following days.

Many of us like to see other folks RPL and SysRPL code and techniques, even if we're shy about asking. Though typically the next stage, having quickly overcome shyness, is proposed changes that will shorten or speed-up your code...

[CosmicTruth]

(06-14-2014 05:05 PM)rprosperi Wrote:  

(06-14-2014 01:29 AM)Jacob Wall Wrote:  I have written quite a bit of software for this machine as is evident on my website, and I would be happy to trade ideas or offer input on any 50g related programming, especially related to surveying.

Jacob

Thanks for introduction, you're certainly in the right place! You'll find you get more out of it, and have more fun, by posting and contributing.

Please share a link to your website - and I predict you will see a definite surge in bandwidth usage in the following days.

Many of us like to see other folks RPL and SysRPL code and techniques, even if we're shy about asking. Though typically the next stage, having quickly overcome shyness, is proposed changes that will shorten or speed-up your code...

I agree with you 100%, and as far as Jacob's web site...
I have seen his website, and I don't think he would mind me sharing a link to it.
http://sgss.ca/index.html
The HP 49/50 programs thereon are very good, at least the one I have installed.

[Jacob Wall]

Quote:I agree with you 100%, and as far as Jacob's web site...
I have seen his website, and I don't think he would mind me sharing a link to it.
http://sgss.ca/index.html
The HP 49/50 programs thereon are very good, at least the one I have installed.

Definitely don't mind, thank you, but I certainly do not want to engage in any "advertising" on the forum as I respect the rules and because some of my software is commercial I didn't want to be seen as taking advantage of an audience that may be receptive to my software. Perhaps a reason for lack of posting in the past, but sure do enjoy the programming on the 50g so I'll try to contribute to related topics in the future.

[Peter Murphy]

Hello Jacob,

No surveyor here, but I'm interested in your area calculation: "Calculate the area of a polygon by entering the points along the perimeter. Curved and straight segments can be used."

For straight segments I guess that you use the "surveyor's formula," but it would be interesting to know for sure and in detail. For curved segments I have no guess at all.

Thanks for some words on area for the 50g et al.

[Jacob Wall]

(06-15-2014 02:38 PM)Peter Murphy Wrote:  Hello Jacob,

No surveyor here, but I'm interested in your area calculation: "Calculate the area of a polygon by entering the points along the perimeter. Curved and straight segments can be used."

For straight segments I guess that you use the "surveyor's formula," but it would be interesting to know for sure and in detail. For curved segments I have no guess at all.

Thanks for some words on area for the 50g et al.

Hi Peter,

In very general terms, I calculate the area of a polygon that connects any curved segments from beginning to end of curve, ignoring the curve during the first pass. Next the segment areas of all curve segments are calculated and then added or subtracted from the first polygon area calculation, depending on position of curve relative to the chord. The whole thing is completely automated so that the user only enters the perimeter points. From the help option of the program you're referring to:

-- Straight Segments --
1.Enter point numbers separated by spaces> Eg: 1 2 3 4 5
2.Enter a range of point numbers to be used in sequence> Eg: 1..5

-- Curve Segments --
1.Curve Right, enter BC+CC+EC> Eg: 1+2+3
2.Curve Left, enter BC-CC-EC> Eg: 1-2-3
3.Compound Curves, enter each curve individually> Eg: 1+2+3 3-4-5

Of course point numbers simply are used to refer to a set of x,y coordinates stored in a database. I can post a numerical example to illustrate the math if you're interested.

Jacob

[Peter Murphy]

Hi Jacob,

I'd be most interested in knowing what algorithm you use to calculate the areas of polygons with straight sides, and something about how you implement it.

[HP67]

Very attractive website and good product presentation. Good to see people making a business with the 50g or any HP calculator.

[Jacob Wall]

(06-16-2014 02:49 PM)Peter Murphy Wrote:  Hi Jacob,

I'd be most interested in knowing what algorithm you use to calculate the areas of polygons with straight sides, and something about how you implement it.

For the polygon with straight sides I use the DMD method. Consider a shape with two curves for example. To calculate the initial polygon area we can just pretend that the curves are not present and instead straight lines are joining the ends instead.



The DMD method works by multiplying the X-Coordinate value of a point with the Y-Coordinate value of the point following it in sequence around the perimeter. Likewise the Y-Coordinate is multiplied by the following point's X-Coordinate value. Assuming we are going in a clockwise direction joining points 1-2-4-5-7-8-9-10-1 to complete the loop. See the spreadsheet below. First take X of Point 1 and multiply by Y of Point 2 = 100, then X of Point 2 and multiply by Y of Point 4 = 225, etc. and looping back around to the first Point. Then you take the sum of all these multiplications and arrive at 2250. Next take Y of Point 1 and multiply by X of Point 2 = 150, etc. and arrive at a sum of 2750. Take one sum and subtract the other (2750-2250=500) then divide by 2 (500/2=250) which is your area in square units. The sign of the final answer indicates whether the order of calculation was done in a clockwise or counter-clockwise direction. If the direction is of no consequence simply take the absolute value. The direction is very helpful to extract here when curves are involved.



As to how I implemented this, below is a simplified User RPL version of the System RPL code I use. Assume XCoords and YCoords are local variables, and are lists of the point coordinates, x and y respectively ordered by sequence. The \GSLIST command is the List summation command.

Code:

  XCoords
  YCoords
  OVER
  DUP
  TAIL
  SWAP
  HEAD
  +
  OVER
  *
  \GSLIST
  UNROT
  DUP
  TAIL
  SWAP
  HEAD
  +
  *
  \GSLIST
  -
  2.
  /

Pretty straight forward, then to calculate the segment areas of any curves and apply as necessary.

Example of how the input process works with the points stored in a database:


Area is calculated and displayed:


Optionally plot the polygon:


Have I just confused you or does that make sense?

Jacob

[Jacob Wall]

(06-16-2014 02:56 PM)HP67 Wrote:  Very attractive website and good product presentation. Good to see people making a business with the 50g or any HP calculator.

Thank you, the web design and coding stuff is also fun, although I keep it very simple with just HTML, CSS and a bit of javascript.

Business is a generous term here, a hobby for the love of doing it, with a small income to pay for the expenses associated. It would be terrific if an Android sized crowd was using the 50g...

Jacob

[Peter Murphy]

Hi Jacob,

Thanks for your detailed reply in Post #13.

I immediately recognized your command sequence DUP HEAD SWAP TAIL SWAP +, presumably operating on lists of X and Y coordinates, because I use that very sequence on a list of [X Y] vectors. Then, where you use *, and I use CROSS.

This method has a long history, reaching back to Gauss and even earlier:

<http://en.wikipedia.org/wiki/Polygon>

It's nice to have confirmation that it really is a Surveyor's formula.

[Thomas Klemm]

(06-17-2014 03:10 PM)Peter Murphy Wrote:  Then, where you use *, and I use CROSS.

Do you mean like this?

Cheers
Thomas

[Tim Wessman]

So i've been sitting on my old DC50 software surveying software for quite a while now meaning to get the source into shape (remove serial number checking, etc) and making build instructions so it could be posted onto hpcalc.org

Anyone interested in helping with that? The interest would not be to lock it down or restrict use - rather I'd be happy if someone took parts and integrated into other packages/software or even just continued working on it.

Not familiar with it? Here's a review:
http://www.amerisurv.com/PDF/TheAmerican...il2007.pdf
Here is the product manual (280 pages or so):
http://pssllc.com/download/DC50_Manual_Jan2008.pdf

[CosmicTruth]

(06-17-2014 04:35 PM)Tim Wessman Wrote:  So i've been sitting on my old DC50 software surveying software for quite a while now meaning to get the source into shape (remove serial number checking, etc) and making build instructions so it could be posted onto hpcalc.org

Anyone interested in helping with that? The interest would not be to lock it down or restrict use - rather I'd be happy if someone took parts and integrated into other packages/software or even just continued working on it.

Not familiar with it? Here's a review:
http://www.amerisurv.com/PDF/TheAmerican...il2007.pdf
Here is the product manual (280 pages or so):
http://pssllc.com/download/DC50_Manual_Jan2008.pdf

This looks nice, in my research I have attempted to find your web site but just a blank page loads for the home screen at http://www.pssllc.com/

I'll help some, it looks finished.

[Jacob Wall]

(06-17-2014 04:35 PM)Tim Wessman Wrote:  So i've been sitting on my old DC50 software surveying software for quite a while now meaning to get the source into shape (remove serial number checking, etc) and making build instructions so it could be posted onto hpcalc.org

Anyone interested in helping with that? The interest would not be to lock it down or restrict use - rather I'd be happy if someone took parts and integrated into other packages/software or even just continued working on it.

Not familiar with it? Here's a review:
http://www.amerisurv.com/PDF/TheAmerican...il2007.pdf
Here is the product manual (280 pages or so):
http://pssllc.com/download/DC50_Manual_Jan2008.pdf

Hello Tim,

That would be cool for sure. Quite some time ago either you sent me the SurveyLib sources or I got them from online somewhere where they were made publicly available. Just last week I was looking at some components of it and also the SDLIB sources for some SD file system clues. I would certainly be up for helping with packaging/documenting the use of some of those sources to make them accessible to whomever, and learn a bunch along the way I'm sure. Feel free to email or PM me.

I never implemented any of the code in my packages because I felt that if I was selling something I shouldn't be selling something others had created, but maybe there's a way to integrate parts of it and make that portion fully open source. That route certainly appeals to me.

Jacob

[Jacob Wall]

(06-17-2014 03:10 PM)Peter Murphy Wrote:  Hi Jacob,

Thanks for your detailed reply in Post #13.

I immediately recognized your command sequence DUP HEAD SWAP TAIL SWAP +, presumably operating on lists of X and Y coordinates, because I use that very sequence on a list of [X Y] vectors. Then, where you use *, and I use CROSS.

This method has a long history, reaching back to Gauss and even earlier:

<http://en.wikipedia.org/wiki/Polygon>

It's nice to have confirmation that it really is a Surveyor's formula.

Hello Peter,

It would be interesting to know when/where the DMD area method first came into use, I haven't been able to find an answer to that, but the link you provided talks about many of the same ideas as applied in surveying. And in fact one of the references "Bart Braden (1986). "The Surveyor's Area Formula". The College Mathematics Journal 17 (4): 326–337. doi:10.2307/2686282" I saw and read on http://www.jstor.org/

Jacob