Questions tagged [convergence]

meridian convergence is the angle between true north (i.e., the direction of local meridian) and grid north (i.e., the grid's Y-axis)

Filter by
Sorted by
Tagged with
1
vote
0answers
53 views

proj4js: calculate meridian convergence

Given a projection and coordinates of a single point, how do I calculate the meridian convergence at that point? Is it even possible? I'm unable to find anything useful using Google. If it is not ...
1
vote
0answers
128 views

Precision Ag and UTM declination

I've written an open source Precision Agriculture application called AgOpenGPS that does everything from auto steer, to mapping, implement and section turn on/off, auto headland turns and more. It's ...
1
vote
0answers
108 views

Calculate Grid Convergence Angle within ModelBuilder Model

I am trying to use the 'Calculate Grid Convergence Angle" tool (from Cartography toolbox -> Data Driven Pages) into ModelBuilder. The tool is pretty simple - (1) import, (2) remove no data (3) ...
1
vote
1answer
322 views

Grid convergence

I was trying to overlay the British National Grid (OSGB 1936 UTM projection) onto the Eurostat grid (ETRS 1989 LAEA Europe) and realized that they do not perfectly overlay (after projecting the ...
1
vote
0answers
54 views

meridian convergence local coordinate systems [duplicate]

I am new to the concept of meridian convergence. I understand that it is the angle between True North and Grid North. But I have problems understanding how meridian convergence affects local ...
2
votes
1answer
922 views

How SAGA calulates Convergence Index

I have calculated convergence index on my DEM with SAGA. Output results seems to be ok (values in range -100;100), but I don't understand how it works. Here is some sample data from my DEM: I know ...
6
votes
2answers
21k views

How to calculate grid convergence (True North to Grid North)?

I would like to know how to calculate the grid convergence angle between True North and Grid North for UTM maps. I am using ArcGIS 10.0 (ArcView licence) and have used the Calculate Grid ...
3
votes
1answer
582 views

Declination Diagram

What point on a UTM map does the declination diagram refer to? Is it the centre? Is it the edges? Is there a standard? The central meridian on a UTM map points to true north. Are grid north and true ...
4
votes
1answer
11k views

Applying proper conversion from True to Grid bearing

Assume that Grid North is 1.49 deg W of True North. Also, the magnetic declination is 13.11 deg. If I wanted to take gyroscopic surveys (measured from True North) and then convert them to Grid ...
3
votes
2answers
7k views

How to Calculate North?

I am working for field survey & client requirement is differentiate various north,like magnetic north,true north & grid north.So therefore my question is what is the methodology of calculating ...