private async Task CreateHeatMap()
{
BeginLoadingIcon();
var samples = await sampleTable.ToCollectionAsync();
samplesList = samples.Where(s => s.PatientID == StoredData.getPatientID()).ToList();
//Create a list contains all groups of samples with distance up to 100m
List <List <Sample> > sampleGroups = new List <List <Sample> >();
List <int> sampleIndexesAdded = new List <int>();
int maxGroupCount = 0;
for (int i = 0; i < samplesList.Count; i++)
{
//Get group's index that contains the current sample
int groupIndex = -1;
for (int j = 0; j < sampleGroups.Count; j++)
{
if (sampleGroups[j].Contains(samplesList[i]))
{
groupIndex = j;
break;
}
}
if (groupIndex == -1)
{
sampleGroups.Add(new List <Sample>()
{
samplesList[i]
});
groupIndex = sampleGroups.Count - 1;
sampleIndexesAdded.Add(i);
if (maxGroupCount == 0)
{
maxGroupCount = 1;
}
}
//Find more samples to add this group
for (int j = i + 1; j < samplesList.Count; j++)
{
if (samplesList[i].DistanceTo(samplesList[j]) < 100)
{
if (!sampleGroups[groupIndex].Contains(samplesList[j]) & !sampleIndexesAdded.Contains(j))
{
sampleGroups[groupIndex].Add(samplesList[j]);
sampleIndexesAdded.Add(j);
if (maxGroupCount < sampleGroups[groupIndex].Count)
{
maxGroupCount = sampleGroups[groupIndex].Count;
}
}
}
}
}
foreach (var sampleGroup in sampleGroups)
{
if (sampleGroup.Count > 2)
{
List <Sample> chSampleGroup = HeatMap.ConvexHull(sampleGroup);
var polygon = new MapPolygon();
//Set appearance
polygon.FillColor = HeatMap.GetColorByDensity(sampleGroup.Count, maxGroupCount);
polygon.StrokeThickness = 0;
var geoPosList = new List <BasicGeoposition>();
for (int i = 0; i < chSampleGroup.Count; i++)
{
geoPosList.Add(new BasicGeoposition()
{
Latitude = chSampleGroup[i].Latitude, Longitude = chSampleGroup[i].Longitude
});
}
//Create path
polygon.Path = new Geopath(geoPosList);
//Add to map
mcMap.MapElements.Add(polygon);
}
}
EndLoadingIcon();
}