2782 search results for "GIS"

Presenting results of logistic regression

January 10, 2012
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Presenting results of logistic regression

So my advisor pointed out this 'new' (well, 2004), way of plotting results of logistic regression results. The idea was presented in a 2004 Bulletin of the Ecological Society of America issue (here). I tried to come up with a solution using, what el...

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Presenting results of logistic regression

January 10, 2012
By
Presenting results of logistic regression

So my advisor pointed out this 'new' (well, 2004), way of plotting results of logistic regression results. The idea was presented in a 2004 Bulletin of the Ecological Society of America issue (here). I tried to come up with a solution using, what el...

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John Snow’s famous cholera analysis data in modern GIS formats

January 6, 2012
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John Snow’s famous cholera analysis data in modern GIS formats

In 1854 there was a massive cholera outbreak in Soho, London – in three days over 120 people died from the disease. Famously, John Snow plotted the locations of the deaths on a map and found they clustered around a pump in Broad Street – he suggested that the pump be taken out of service

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Legislative Activity in the Danish Parliament

December 22, 2011
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Legislative Activity in the Danish Parliament

As mentioned in this post, I have been using the powerful combination of the Beautiful Soup and Mechanize modules in Python to build a web scrapers. The amount of data on the web is amazing, and I believe that any quantitatively oriented social scienti...

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Logistic Regression Explained

December 1, 2011
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Logistic Regression Explained

Logistic regression is a type of regression used when the dependant variable is binary or ordinal (e.g. when the outcome is either “dead” or “alive”). It is commonly used for predicting the probability of occurrence of an event, based on several predictor variables that may either be numerical or categorical. For example, suppose a researcher

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Magical RUT with GIST

November 22, 2011
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Magical RUT with GIST

In search of better ways to post my R code, I finally discovered how GIST can help make my R blogging easier.  I know I am way behind, and I apologize to my loyal readers for my shortcomings.  Here is yesterday’s Magical Russell 2000 code u...

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Example 9.14: confidence intervals for logistic regression models

November 15, 2011
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Example 9.14: confidence intervals for logistic regression models

Recently a student asked about the difference between confint() and confint.default() functions, both available in the MASS library to calculate confidence intervals from logistic regression models. The following example demonstrates that they yield d...

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Logistic Power Peak (LPP) Simulated Soil Profiles

November 12, 2011
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Logistic Power Peak (LPP) Simulated Soil Profiles

A friend of mine recently published a very interesting article on the pedologic interpretation of asymetric peak functions fit to soil profile data (Myers et al., 2011). I won't bother summarizing or paraphrasing the article here, as the original artic...

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PostGIS Quickie

November 10, 2011
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Today I needed to cut out a rectangle of geologic data from a state-wide map in an AEA coordinate system, using a bounding box from a UTM zone 10 region, with the output saved in UTM zone 10 coordinates. PostGIS makes this type of operation very simple...

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Machine Learning Ex 5.2 – Regularized Logistic Regression

October 25, 2011
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Machine Learning Ex 5.2 – Regularized Logistic Regression

Now we move on to the second part of the Exercise 5.2, which requires to implement regularized logistic regression using Newton's Method. Plot the data:

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