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<title>Java·Applied·Geodesy·3D - A posteriori reference variance</title>
<link>https://software.applied-geodesy.org/forum/</link>
<description>Support forum for JAG3D software package</description>
<language>en</language>
<item>
<title>A posteriori reference variance (reply)</title>
<content:encoded><![CDATA[<p>Thank you Micha.</p>
<p>Sincerely,<br />
Antonio</p>
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<link>https://software.applied-geodesy.org/forum/index.php?id=340</link>
<guid>https://software.applied-geodesy.org/forum/index.php?id=340</guid>
<pubDate>Wed, 29 May 2019 14:22:28 +0000</pubDate>
<dc:creator>a2pac</dc:creator>
</item>
<item>
<title>A posteriori reference variance (reply)</title>
<content:encoded><![CDATA[<p>Hello,</p>
<blockquote><p>Do you have the correct link?</p>
</blockquote><p>I'm sorry, the protocol (https) was missing. The corrected link reads:  <a href="https://dev.applied-geodesy.org/tmp/Caspary_Congruence_Analysis.zip">Caspary_Congruence_Analysis.zip</a></p>
<p>regards<br />
Micha</p>
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<link>https://software.applied-geodesy.org/forum/index.php?id=338</link>
<guid>https://software.applied-geodesy.org/forum/index.php?id=338</guid>
<pubDate>Wed, 29 May 2019 11:31:25 +0000</pubDate>
<dc:creator>Micha</dc:creator>
</item>
<item>
<title>A posteriori reference variance (reply)</title>
<content:encoded><![CDATA[<p>Micha,</p>
<p>thank you very mutch for your help and answers.<br />
The given link to the <em>example project</em> returns the <strong>404 link not found error</strong>. Do you have the correct link?</p>
<p>Sincerely,<br />
Antonio</p>
]]></content:encoded>
<link>https://software.applied-geodesy.org/forum/index.php?id=337</link>
<guid>https://software.applied-geodesy.org/forum/index.php?id=337</guid>
<pubDate>Wed, 29 May 2019 11:22:26 +0000</pubDate>
<dc:creator>a2pac</dc:creator>
</item>
<item>
<title>A posteriori reference variance (reply)</title>
<content:encoded><![CDATA[<p>Hello Antonio,</p>
<blockquote><p>Firstly, in the initial adjustment steps, JAG3D calculates the weight matrix <strong>P</strong> of all observations. Weights of all observations are calculated based on the given a-priori uncertainty (<em>e.g. a-priori uncertainty of horizontal distance</em>) and a-priori reference variance <strong>σ</strong>. </p>
</blockquote><p>Yes, you are right.</p>
<blockquote><p>The default value of the a-priori reference variance σ is 1, and can't be changed in JAG3D. Are the stated facts correct?</p>
</blockquote><p>Yes, the (a-priori) variance of the unit weight is set to <code>σ = 1</code>. The variance of the unit weight does not affect the estimates (parameters and dispersion). </p>
<blockquote><p>Furthermore, during the adjustment procedure JAG3D calculates the <strong>a-posteriori reference variance factor</strong> and uses it to calculate all confidence measures defined by the adjustment model. Where does JAG3D directly shows the calculated a-posteriori reference variance factor?</p>
</blockquote><p>The estimated variance of the unit weight is part of the variance-component estimation (vce). Thus, results are presented in the <a href="https://software.applied-geodesy.org/wiki/user-interface/editor#globale_ausgleichungsergebnisse">Table of the vce</a>.</p>
<blockquote><p>Next, after the adjustment of two consecutive epochs, during the deformation analysis, does JAG3D calculates and shows the <strong>displacement vector</strong> between the points of the two measured epochs?</p>
</blockquote><p>Yes. The 2D displacement vectors are shown, see for instance <a href="https://www.researchgate.net/publication/325226422_Auswerte-_und_Analysestrategie_fur_automatisierte_untertagige_Uberwachungsmessungen">Fig. 3 in this contribution</a>.</p>
<blockquote><p>And finally, let's say I have a 2D geodetic network measured in two consecutive epochs. The network is adjusted as a <em>free network</em> (<em>the minimum trace datum is defined</em>). My goal is to determine if unstable points exist in the network (between epochs) and to calculate the deformation vector of the unstable points. What would be the <strong>general workflow</strong> (<em>main steps</em>) in JAG3D to accomplish the above stated goal? </p>
</blockquote><p>Please take a look on this <a href="https://dev.applied-geodesy.org/tmp/Caspary_Congruence_Analysis.zip">example project</a>. The reference point number <code>3</code> is unstable. The next step is to duplicate point <code>3</code> and to rename the points, e.g. <code>3_E1</code> and <code>3_E2</code> for reference and control epoch, respectively. Move <code>3_E1</code> and <code>3_E2</code> to a new point group (point 3 is unstable and should not define the datum). Introduce the new point names in the corresponding observation groups (,i.e., rename the point <code>3</code> by <code>3_E1</code> in reference epoch and rename the point by <code>3_E2</code> in control epoch. Define a &quot;link&quot; <code>3_E1 - 3_E2</code> to estimate the teststatistics of the displacement.</p>
<p>Kind regards<br />
Micha</p>
]]></content:encoded>
<link>https://software.applied-geodesy.org/forum/index.php?id=336</link>
<guid>https://software.applied-geodesy.org/forum/index.php?id=336</guid>
<pubDate>Tue, 28 May 2019 15:10:41 +0000</pubDate>
<dc:creator>Micha</dc:creator>
</item>
<item>
<title>A posteriori reference variance</title>
<content:encoded><![CDATA[<p>Hallo,</p>
<p>I have been studying JAG3D through my concrete project of a geodetic network adjustment and deformation analysis. Furthermore, I have read almost all the topics in this forum and the user manual guidelines, and have some questions and uncertainties I hope you will answer me.</p>
<p>Firstly, in the initial adjustment steps, JAG3D calculates the weight matrix <strong>P</strong> of all observations. Weights of all observations are calculated based on the given a-priori uncertainty (<em>e.g. a-priori uncertainty of horizontal distance</em>) and a-priori reference variance <strong>σ</strong>. The default value of the a-priori reference variance σ is 1, and can't be changed in JAG3D. Are the stated facts correct?</p>
<p>Furthermore, during the adjustment procedure JAG3D calculates te <strong>a-posteriori reference variance factor</strong> and uses it to calculate all confidence measures defined by the adjustment model. Where does JAG3D directly shows the calculated a-posteriori reference variance factor?</p>
<p>Next, after the adjustment of two consecutive epochs, during the deformation analysis, does JAG3D calculates and shows the <strong>displacement vector</strong> between the points of the two measured epochs?</p>
<p>And finally, let's say I have a 2D geodetic network measured in two consecutive epochs. The network is adjusted as a <em>free network</em> (<em>the minimum trace datum is defined</em>). My goal is to determine if unstable points exist in the network (between epochs) and to calculate the deformation vector of the unstable points. What would be the <strong>general workflow</strong> (<em>main steps</em>) in JAG3D to accomplish the above stated goal? </p>
<p>I would very much appreciate if you took the time to read and answer my questions.</p>
<p>Thank you,<br />
Antonio</p>
]]></content:encoded>
<link>https://software.applied-geodesy.org/forum/index.php?id=335</link>
<guid>https://software.applied-geodesy.org/forum/index.php?id=335</guid>
<pubDate>Tue, 28 May 2019 11:56:34 +0000</pubDate>
<dc:creator>a2pac</dc:creator>
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