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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)

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Is there a easy way to get the Grid convergence in QGIS?

Is there an easy way to get the angular difference between Grid North & True North in QGIS? This is how I do it: Make a map in print composer Set the map CRS to whatever "WGS 84 / UTM zone&...
SubXi's user avatar
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Calculate UTM grid convergence using UTM coordinates

What would be the simplest way to arrive at a value for UTM grid convergence for a point given in UTM coordinates? All advice I can find requires that the point be given in latitude/longitude. For ...
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Calculating Grid Convergence

When ESRI tool "Calculate Grid Convergence Angle (Cartography)" is used to calculate line bearing or azimuth, is the bearing referenced to True North or Grid North?
Adeleke Adejobi's user avatar
4 votes
1 answer
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Calculating convergence angle for point data in QGIS

I have been a user of ArcGIS Desktop for many years and this function is easily done within ArcMap using the 'Calculate Grid Convergence Angle (Cartography)' tool. I am wondering if there is a ...
Aaron's user avatar
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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 ...
theDmi's user avatar
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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 ...
Briantee's user avatar
1 vote
0 answers
198 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) ...
kdubz's user avatar
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2 votes
1 answer
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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 ...
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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 ...
loesbrown's user avatar
3 votes
2 answers
3k views

How SAGA calculates 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 ...
ami's user avatar
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Calculating 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 Convergence ...
rwoods's user avatar
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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 ...
Jeff George's user avatar
5 votes
1 answer
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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 ...
Mr. Cox's user avatar
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4 votes
2 answers
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How to Calculate North?

I am working on a field survey and a client requirement is to differentiate various norths, like magnetic north, true north and grid north. My question is what is the methodology of calculating north ...
Mahesh Jadhav's user avatar