Harold Dendy
Member
JFIELD USERS: (My setup: LS+ and T3)
I finished a job a couple of days ago and had to get "close enough" to a pre-determined area. I had trouble understanding and following the logic in the JField parallel line method software.
I had four fixed points and needed to slide a line to get a pre-determined area. I calculated my area from the four points and then obtained the area needed for my final acreage. I wanted to slide a line away from the center of the polygon to increase the area to obtain my required area.
My computer CAD program easily does this when I specify P1 and P2, then specify a direction from P1 and P2. Then it allows me to specify the direction of the line needed. No problem.
The problem I ran into with JField is that this method is difficult to work with and understand. I did manage to input my four points, and then get my first and second nodal points selected so that the parallel line would be defined, but I was unable to specify a negative area to "add" to the four-point area to increase the size of the parcel to the required area. The software input would not allow a negative area, even when using the recall memory function of the calculator with a negative number, it would drop the negative sign and would upload as a positive number. The HELP menu says I can CUT or ADD an area, but the COGO function only allows a KEEP or CUT, either in square units or a percent. When I used the KEEP function using a positive area, a polygon was created that contained the area to be added going toward the center of the polygon, which was the wrong direction; I needed it added to my polygon. I tried the CUT function but got the same results - wrong direction. I could not figure out how to make the software ADD the needed area to my existing polygon.
I solved my problem by trial and error. I calculated the distance between my C1 and C2 points, and then got my distance to move a parallel line away to new points C3 and C4. I re-calculated the area and got another needed area, then utilized the distance between C3 and C4 to get my parallel line offset for yet another new polygon. This time, I got a few thousandths of an acre different than what I needed, and another iteration of moving a 420-foot line a distance of a few hundredths of a foot would have been pointless. I called it good enough and set the corners on my new C3 and C4 points and then measured the final coordinates.
A work-around that I could have utilized in hindsight would be to COGO in a polygon that would be larger than the area needed, and then use the parallel line method to cut the unneeded area out.
I am looking for input from other users regarding how they work with pre-determined areas. I would appreciate input and comments from users.
Here is a thumbnail of what I was working on.
I finished a job a couple of days ago and had to get "close enough" to a pre-determined area. I had trouble understanding and following the logic in the JField parallel line method software.
I had four fixed points and needed to slide a line to get a pre-determined area. I calculated my area from the four points and then obtained the area needed for my final acreage. I wanted to slide a line away from the center of the polygon to increase the area to obtain my required area.
My computer CAD program easily does this when I specify P1 and P2, then specify a direction from P1 and P2. Then it allows me to specify the direction of the line needed. No problem.
The problem I ran into with JField is that this method is difficult to work with and understand. I did manage to input my four points, and then get my first and second nodal points selected so that the parallel line would be defined, but I was unable to specify a negative area to "add" to the four-point area to increase the size of the parcel to the required area. The software input would not allow a negative area, even when using the recall memory function of the calculator with a negative number, it would drop the negative sign and would upload as a positive number. The HELP menu says I can CUT or ADD an area, but the COGO function only allows a KEEP or CUT, either in square units or a percent. When I used the KEEP function using a positive area, a polygon was created that contained the area to be added going toward the center of the polygon, which was the wrong direction; I needed it added to my polygon. I tried the CUT function but got the same results - wrong direction. I could not figure out how to make the software ADD the needed area to my existing polygon.
I solved my problem by trial and error. I calculated the distance between my C1 and C2 points, and then got my distance to move a parallel line away to new points C3 and C4. I re-calculated the area and got another needed area, then utilized the distance between C3 and C4 to get my parallel line offset for yet another new polygon. This time, I got a few thousandths of an acre different than what I needed, and another iteration of moving a 420-foot line a distance of a few hundredths of a foot would have been pointless. I called it good enough and set the corners on my new C3 and C4 points and then measured the final coordinates.
A work-around that I could have utilized in hindsight would be to COGO in a polygon that would be larger than the area needed, and then use the parallel line method to cut the unneeded area out.
I am looking for input from other users regarding how they work with pre-determined areas. I would appreciate input and comments from users.
Here is a thumbnail of what I was working on.
