topic Re: [.NET] Get DTED Data (Elevation) Between Two Points in ArcObjects SDK Questions

[.NET] Get DTED Data (Elevation) Between Two Points

oyleiste — Thu, 04 Apr 2013 14:10:09 GMT

Dear All,

I want to get DTED data (elevation) between two points (on a line).
Is there any built-in function for this purpose or I should implement it on my own?

What I want is similar to Linear Line of Sight (LLOS), but it should be on a direct line. I want to check if there is collision between two points or not.

Thank you
Sincerely

Re: [.NET] Get DTED Data (Elevation) Between Two Points

Santosh_Pavan_KumarNukala — Fri, 05 Apr 2013 06:29:32 GMT

Dear All,

I want to get DTED data (elevation) between two points (on a line).
Is there any built-in function for this purpose or I should implement it on my own?

What I want is similar to Linear Line of Sight (LLOS), but it should be on a direct line. I want to check if there is collision between two points or not.

Thank you
Sincerely

Hi,
This might be a junk solution..given two points, you could divide the line joining source and destination points into very minute equal distanced sampling points, get the elevation at each sampling point. Then calculate slopes at every consecutive points and compare with next set of consecutive points. For example there are 3 consecutive sampling points A, B,C and say the slope or Tan theta between A and B is 60 degrees, slope between B and C is 120 degrees .. then A is not in LLOS with C. This is how Line of sight algorithm works internally.. you need to repeat this process with all sampling points and assign green and Red colors appropriately for those in LLOS and not in LLOS respectively. I had gone through Line of Sight AML in ArcInfo Workstation few years back and this is how it works internally. Hope this helps

Regards,
Pavan

Re: [.NET] Get DTED Data (Elevation) Between Two Points

oyleiste — Sat, 06 Apr 2013 07:06:43 GMT

Thank you very much for your reply.

Well, I did something similar to your suggestion. I create a polyline (which is a single line indeed) using FROM and TO points. Then, I get elevation of 100 points between FROM and TO points.

It works. But I should replace 100 with significant data.

Thank you again for your helpful reply. I appreciate it.
Sincerely

Re: [.NET] Get DTED Data (Elevation) Between Two Points

Santosh_Pavan_KumarNukala — Mon, 08 Apr 2013 10:19:41 GMT

Thank you very much for your reply.

Well, I did something similar to your suggestion. I create a polyline (which is a single line indeed) using FROM and TO points. Then, I get elevation of 100 points between FROM and TO points.

It works. But I should replace 100 with significant data.

Thank you again for your helpful reply. I appreciate it.
Sincerely

Fixing the number of Sample points would not be right, in which case the distance between consecutive points might vary depending upon distance between FROM and TO points. The work around I suggest would be instead of taking the number of sampling points as constant (100 in this case), take the interval (in distance) between two successive points as constant. For example assuming the distance between two successive points is 1 meter, if the distance between FROM and TO points is 100 meters, you get 100 sample points, if it is 150 meters you get 150 sample points. In this case you need to calculate the distance between FROM and TWO points and divide with your interval to get number of points. This is better than taking 100 sample points everytime. Hope this helps.

Regards,
Pavan