/// <summary>
/// Gets the extent of the geometry.
/// </summary>
/// <param name="geometry">A <see cref="T:Geocrest.Model.ArcGIS.Geometry.Geometry"/>
/// containing a point, polyline, or a polygon.</param>
/// <returns>
/// Returns the extent of the <see cref="T:Geocrest.Model.ArcGIS.Geometry.Geometry"/>.
/// </returns>
/// <exception cref="T:System.NullReferenceException">If the output extent doesn't have valid values.</exception>
/// <exception cref="T:System.NotSupportedException"><paramref name="geometry"/> is not a
/// point, polyline, polygon, or envelope.</exception>
/// <remarks>Note that if the input is a point, the output will be an envelope constructed
/// aroung the point width a width and height of 100 map units.</remarks>
public static Geocrest.Model.ArcGIS.Geometry.Geometry GetExtent(this
Geocrest.Model.ArcGIS.Geometry.Geometry geometry)
{
double?xmin = null, ymin = null, xmax = null, ymax = null;
if (geometry.Rings != null || geometry.Paths != null)
{
double[][][] array = geometry.Rings != null ? geometry.Rings : geometry.Paths;
if (array != null)
{
foreach (double[][] ring in array)
{
foreach (double[] path in ring)
{
if (!xmin.HasValue || path[0] < xmin)
{
xmin = path[0];
}
if (!xmax.HasValue || path[0] > xmax)
{
xmax = path[0];
}
if (!ymin.HasValue || path[1] < ymin)
{
ymin = path[1];
}
if (!ymax.HasValue || path[1] > ymax)
{
ymax = path[1];
}
}
}
}
if (!(xmin.HasValue || ymin.HasValue || xmax.HasValue || ymax.HasValue))
{
throw new NullReferenceException();
}
return(new Geocrest.Model.ArcGIS.Geometry.Geometry
(xmin.Value, ymin.Value, xmax.Value, ymax.Value, geometry.SpatialReference));
}
else if (geometry.GeometryType == esriGeometryType.esriGeometryPoint)
{
return(geometry.ConstructEnvelope(100, 100));
}
else if (geometry.HasProperty("xmin") && geometry.HasProperty("ymin") && geometry.HasProperty("xmax") &&
geometry.HasProperty("ymax"))
{
return(geometry);
}
else
{
throw new NotSupportedException("Invalid geometry type");
}
}
/// <summary>
/// Expands the specified envelope by the specified zoom factor. If the zoom factor is
/// greater than 1, the envelope will increase in size; if the zoom factor is less than 1,
/// the envelope will decrease in size. A zoom factor of 1 will return the same envelope.
/// </summary>
/// <param name="envelope">The <see cref="T:Geocrest.Model.ArcGIS.Geometry.Geometry"/>
/// envelope to expand.</param>
/// <param name="zoom">The desired expansion level: if greater than 1, the envelope will
/// zoom out; if less than 1, it will zoom in.</param>
/// <returns>The expanded/contracted envelope.</returns>
/// <exception cref="T:System.NotSupportedException">If the input geometry is not an envelope.</exception>
public static Geocrest.Model.ArcGIS.Geometry.Geometry Expand(this
Geocrest.Model.ArcGIS.Geometry.Geometry envelope, double zoom)
{
//if not an envelope throw an error
if (!(envelope.YMin.HasValue || envelope.XMin.HasValue || envelope.YMax.HasValue ||
envelope.XMax.HasValue))
{
throw new NotSupportedException("Geometry type must be an envelope.");
}
double width, height, xfactor, yfactor, addwidth, addheight;
width = envelope.XMax.Value - envelope.XMin.Value;
height = envelope.YMax.Value - envelope.YMin.Value;
xfactor = width * zoom;
yfactor = height * zoom;
addwidth = xfactor - width;
addheight = yfactor - height;
return(new Geocrest.Model.ArcGIS.Geometry.Geometry(envelope.XMin.Value - (addwidth / 2),
envelope.YMin.Value - (addheight / 2), envelope.XMax.Value + (addwidth / 2),
envelope.YMax.Value + (addheight / 2), envelope.SpatialReference));
}
/// <summary>
/// Constructs an envelope around an input point.
/// </summary>
/// <param name="point">A <see cref="T:Geocrest.Model.ArcGIS.Geometry.Geometry"/> point.</param>
/// <param name="height">The desired height of the envelope.</param>
/// <param name="width">The desired width of the envelope.</param>
/// <returns>
/// Returns an envelope as a <see cref="T:Geocrest.Model.ArcGIS.Geometry.Geometry"/> object.
/// </returns>
/// <exception cref="T:System.NotSupportedException">If the input is not a valid point.</exception>
public static Geocrest.Model.ArcGIS.Geometry.Geometry ConstructEnvelope(this
Geocrest.Model.ArcGIS.Geometry.Geometry point, double height, double width)
{
if (point.GeometryType == esriGeometryType.esriGeometryPoint && point.X.HasValue &&
point.Y.HasValue)
{
Geocrest.Model.ArcGIS.Geometry.Geometry returnEnv =
new Geocrest.Model.ArcGIS.Geometry.Geometry
{
XMax = point.X.Value + (width / 2),
XMin = point.X.Value - (width / 2),
YMax = point.Y.Value + (height / 2),
YMin = point.Y.Value - (height / 2)
};
return(returnEnv);
}
else
{
throw new NotSupportedException("Only esriGeometryPoint is supported.");
}
}
