Showing posts with label geographic information system. Show all posts
Showing posts with label geographic information system. Show all posts

Sunday, December 13, 2020

Testing Rates are Higher in Downtown Johnstown but There Are More Cases of COVID-19 in the Rest of Cambria County

Yesterday WJAC TV reported that Cambria County had the highest rate of new cases in the nation.  Looking at the New York Times COVID-19 today, the county (which is listed a Johnstown because the county is the Johnstown metropolitan statistical area) ranks 6th today.  Last week I posted on the elevated mortality rate in the county since Trump came here.  This week I will look at the distribution of cases and testing in Cambria County.

On April 26th this is what the distribution of cases looked like for Cambria County at the zip code level.  You can see a lot of white zip codes where there are no cases.  I started tracking testing at the zip code level on May 12.  On that day, 56.3% of the testing in the county was in the greater Johnstown area which I define as the zip codes 15901 through 15909.  The cases were not tracked then because if the cases were between 1 and 4 in that zip code, the exact number of cases was redacted.

The second map is from July 1 where we can see clustering of cases around Johnstown in the southwest corner of the county and in Ebensburg which is in the center of the county.  On this date 55.4% of te testing was in the Greater Johnstown area.  The cases in many zip codes were still redacted at this time.

This image is from October 27th.  In this image I have the 15901 zip code highlighted which is downtown Johnstown.  There were 30 confirmed cases there and the number of probable cases was redacted because there were between 1 and 4 persons with this designation to protect individual privacy.  We can also see an increase in cases in the 15931 zip code where Ebensburg is located with 200 cases.  The increase in Ebensburg is at least partly due to an outbreak at the local county jail.  On this date, 47.8% of the testing was in the Greater Johnstown area while only 36.4% of the cases were there.  

The image above is from today ,December 13.  We can see that the 15901 zip code now has 172 conformed and 19 probable cases for a total of 191 cases.  The 15904, 15905, and 15931 zip codes are darker colored because they have more than 500 cases.  Today 46.7% of the total test results are in Greater Johnstown (and thus 53.3% of the testing is in the remainder of the county) while only 40.2% of the cases are (with 59.8% of the cases in the remainder of the county).  This indicates that the rise in testing in the remainder of the county lags behind the rise in cases there.  Greater Johnstown accounts for 50% of the county's population.  The table below shows the rates of testing and cases for each Johnstown zip code, Ebensburg and Cambria County.  There's no room for US and Pennsylvania data on this page but you can see it on google sheets at the Johnstown zip code testing tab








total Johnstown

15931 (Ebensburg)

Cambria County











Testing 12/13/2020










Testing rate 12/13/2020










cases 12/13/2020










Positive rate 12/13/2020










Cases per 100k 12/13/2020










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Wednesday, July 15, 2020

A Look at Positive COVID-19 Testing Rates in Cambria, PA, and the US

There have been recent media reports about positive testing rates increasing in Pennsylvania.  I thought I would take a closer look at positive test rates since they were reported by the state on April 17. The positive testing rate is simply the number of positive tests divided by the total number of tests.  The graph above shows the cumulative positive test rates for the US (orange line), PA (red line), and Cambria County (blue dotted line).  The black line shows the daily positive testing rate for Cambria County.  

The positive rate for the state has been consistently higher than the US and county rates.  Both rates have been decreasing as testing has become more readily available.  Cambria's positivity rate has been consistently lower than the state and US rates.  The daily testing rate for the county on April 13 was high because on that day there were three positive tests out of 16 total tests (18.25%).  

Since June 24, the cumulative positive test rate increased from 1.02% to 1.28% as of today.  This rise may not sound like much but the solid black line shows positive rates that were consistently at or above the cumulative rates for this period with one day being higher than 5% on July 11.  

The graph above is from the Johns-Hopkins Univeristy site tracking the Corona Virus Pandemic.  It shows the trend in testing for the US during the pandemic.  The blue line shows the seven day average of positive test % with a steady decrease from early April (21.9%) until the middle of June (4.4%) with an increase to 8.7% today.

This graph shows the trend in testing for the state of Pennsylvania for the same period.  Here, we see that there was a corresponding peak in mid April in the positive rate at 27.8% to 3.4% around June 21.  This decrease was followed by an increase to 5.5% as of today.  We can see that testing has risen at a slower rate in the state than in the US as a whole.

The black line in the graph at the top was replaced with the 7 day moving average in testing which does show a rise in positive tests after June 24.  I did not have the same access to 
testing data that Johns-Hopkins had.  I used publicly available data that the PA health department provided beginning on April 17.  

The graph below shows the comparison of the positive testing rate (in the red line) to the testing rate as a percentage of the population for six Johnstown zip codes, the overall rates for Greater Johnstown, Cambria County, Pennsylvania, and the US. These rates are cumulative.  The numbers at the top of each bar are the cumulative testing rates as a percentage of the population.  It's interesting that the state has a higher cumulative positive rate (10.08%) than its testing rate (7.57%).  Johns-Hopkins testing tracker has the state ranked 47th in the testing rates over the last two weeks (1.1 per 1,000) while it ranks 37th in the two week average positive testing rate (5.5%).  At the bottom is a summary of testing data for Pennsylvania.  How one frames the statistics makes all the difference.

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Wednesday, July 1, 2020

A Second Wave of COVID-19 Cases in Cambria and Allegheny Counties?

Cambria County has experienced 22 new cases of COVID-19 in the last 7 days to give a total of 83 cases.  In the previous 37 days, the county had a net increase of 7 cases.  The best fit line is now a fifth order polynomial with an R-square of 99%.  In the graph below, a second order polynomial provided the best fit for the cumulative case curve for the months of March and April with an R-square of 97%.

The map above shows the distribution of the 83 cases in Cambria County by zip code.  The lightest blue zip codes have zero confirmed or probable cases.  The next darker color blue zip codes have between 1 and 4 cases.  The next darker blue colored zip codes have between 5 and 10 cases.  The zip code with the most confirmed cases is 15904 with 7 cases. This zip code covers Richland Township followed by 15931 (Ebensburg) at 6, the Johnstown zip codes of 15905 and 15902 and the Portage zipcode 15946 with 5 each.  The most tested zip code in Johnstown is 15901 with enough tests to cover 12.32% of it's population.  The image below is a screenshot of the distribution of cases on April 26 showing all of the light blue zip codes with the number of cases between 1 and 4.

So far there hasn't been an increase in the number of deaths which tend to follow an increase in cases.  Allegheny County has been showing a similar rise in cases, over 400 in the last five days.  So far they have not had a corresponding increase in deaths.  The bars have been closed down in Allegheny County but not in Cambria County so far.  WEAR A Mask!!!!


WTAE in Pittsburgh reports that it is now mandatory to wear masks in publicBelow is a graph showing the trend in testing and cases in the county since March.

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Sunday, May 24, 2020

This week's Coronavirus Observations

Having looked at the trends in testing and cases of Coronavirus for Cambria County, Pennsylvania, and the US for the past few months, I have little new observations to make from last week except for:

  • The number of tests being conducted per day in Cambria County is increasing for the county but the number of new cases per day in the county has leveled off.
  • Although the testing rate has increased, we can see from the graph above that:
    • the county lags behind the city, state, and the U.S. 
    • the city lags behind the state and U.S. (except for zip code 15201)
    • the state lags behind the U.S.
  • This week the state department of health changed how it reports the number of deaths in the state as the number of deaths has surpassed 5,000.  It makes it harder for me to put the numbers together for my Google Sheets but not impossible.  The chart above shows how the case mortality for the state has surged past the U.S. rate.  I don't have information on how the state compares to the other states in the case mortality rate.
  • The state unemplyment rate for April 2020 rose to 15.1% which was up from 5.8% in March and 4.7% in February.  The state rate was higher than the U.S. rate of 14.7%.  
    • The April rates for Cambria County have not been released yet.  For March it was 7.4% up from 5.7% in February.

The county is now in the yellow phase and may return to the green phase after June 2.  COVID Cast from Carnegie Mellon University predicts that the number of new cases will be decreasing for the near future.  It remains to be seen what will happen to the number of cases once restrictions are dropped.

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Saturday, March 21, 2020

Corona Numbers from the WHO and JHU

Week 2 of the state of emergency is upon us.  Last week I posted numbers from the World Heath Organization's (WHO) Corona Virus dashboard showing the progression in the number of cases worldwide.  Above is the cumulative frequency graph and overall numbers from their dashboard last week.  

At the left is the WHO's world wide cumulative frequency chart from today.  The number of cases increased by 123,535 or 87%.  The number of deaths increased by 5,793 or 107%.  

The two curves show that after the curve was starting to flatten out (mostly in China), it began to increase exponentially in early March everywhere but China.  The mortality rate for the total number of cases a week ago was 3.8%.  Currently the rate is 4.2% with it being the highest in Italy where it is 8.6%.

Johns-Hopkins University (JHU) also has a dashboard that is frequently cited in the news media.  Their reported numbers are higher than the WHO's. They report 287,238 cases worldwide with 11,942 deaths.  The mortality rate according to their numbers is also 4.2%.  

The JHU dashboard also provides the numbers of people who have recovered from the virus.  According to them, 89,899 have recovered worldwide from the virus or 31% of the total cases. The graph above shows the cumulative number of cases in mainland China (orange line) and the cumulative number of cases everywhere else (yellow line).  We can see that the yellow line is still growing while china's line has flattened.  The number of recovered cases has been growing steadily.

Top 10 Countries with Cases according to WHO and JHU and the differences between numbers
World health Organization
Johns Hopkins University
Difference Between Countries
S Korea 
S Korea
S Korea 
United Kingdom 
United Kingdom
United Kingdom 

The numbers for each country differ between the two dashboards.  The top 10 countries with cases are presented above with the number of cases reported.  The two dashboards agree on the countries in the top 10.  The order that the countries are ranked agree except for Iran and Germany which are flipped for fourth and fifth.  The two dashboards agree on the number of cases only for Italy and South Korea.  The greatest discrepancies for the two dashboards are for Spain (-5,394), the US (-4,712), and Germany (-3,329) with JHU having more cases.

Certainly there is confusion keeping track of all the cases in a world with more than 7 billion inhabitants.  The countries most affected are some of the richest and most powerful in Asia, Europe, and North America with the exception of Iran.  Until the curve of new cases flattens out the state of emergency is likely to continue.  The video below gives a good summary of how epidemics and pandemics progress.

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