Question: When I tried to draw circle on JMapViewer with the following parameters:

Latitude:30.58654740901267
Longitude:31.504483034999993
radius : 100

I got the following gigantic circle
![enter image description here](https://i.stack.imgur.com/7Y3Ig.png)

**What is the measurement unit used for this radius variable ?!!**

**code below**

```
MapMarkerCircle circle = new MapMarkerCircle(c, 100);
Color color = new Color(50, 0, 0,100);
circle.setBackColor(color);
mapViewer.addMapMarker(circle);

```

Answer: 
```
#include <stdio.h>
#include <string.h>
#include <time.h>

int main(void) {
  time_t t = time(0);                      // NOW
  struct tm tm[1];
  memmove(tm, localtime(&t), sizeof tm);   // convert to struct tm
  tm->tm_mday -= 90;                       // subtract 90 days
  time_t then2 = mktime(tm);               // convert to time_t and normalize
  printf("%s\n", ctime(&then2));
  return 0;
}

```
Not a single function, no.

But you can quite easily do this:

* Obtain current time using [`time()`](http://linux.die.net/man/2/time).
* Subtract 90 days' worth of seconds.
* Convert to local time using [`localtime()`](http://linux.die.net/man/3/ctime).
* Convert to string using [`strftime()`](http://linux.die.net/man/3/strftime) if needed.