Depending on definition used, there are approximately 200 amphitheaters in the Roman world. While this document does not include data for all of them, it is probably a meaningful sample.
The original data used to compile these charts and tables is available at https://github.com/sfsheath/roman-amphitheaters . It is available there in the following formats (some of which may lag the geojson file):
The PURL URI http://purl.org/roman-amphitheaters redirects to the geojson version, which is canonical for the time being.
Summary statistics as produced by R’s summary() function.
## capacity extmajor arenamajor elevation
## Min. : 1000 Min. : 70.00 Min. :30.00 Min. :-121.0
## 1st Qu.: 8000 1st Qu.: 94.25 1st Qu.:54.50 1st Qu.: 33.0
## Median :15000 Median :117.80 Median :66.00 Median : 99.0
## Mean :15857 Mean :118.96 Mean :61.86 Mean : 189.2
## 3rd Qu.:20350 3rd Qu.:135.75 3rd Qu.:71.50 3rd Qu.: 264.5
## Max. :50000 Max. :189.00 Max. :83.00 Max. :1170.0
## NA's :120 NA's :153 NA's :151
## longitude
## Min. :-8.493
## 1st Qu.: 2.947
## Median :10.866
## Mean :10.451
## 3rd Qu.:14.564
## Max. :40.729
##