Orthographic
Stereographic
LambertEqualArea
Gnomonic
AzimuthalEquidistant
Satellite
Mollweide
Mercator
CylindricalEquidistant
LambertConformal
Default: CylindricalEquidistant
Default: 0.0
Default: 1.0
Default: 0.0
Default: 1.0
LambertConformal
. Its value must lie between -90.0 and
+90.0, where -90.0 represents the South Pole and +90.0 represents the
North Pole.
Default: 0.0
LambertConformal
. Its value must lie between -180.0 and
+180.0, where both extremes represent the longitude of the
International Dateline.
Default: 0.0
LambertConformal
.
Default: 0.0
This resource of type NhlTMapLimitMode specifies how MapTransformation determines the extent of the projected globe that is mapped into the viewport area. It has eight possible settings:
MaximalArea
LatLon
Angles
Depending on the projection, the maximum allowable value for each of the angle resources varies, as follows:
Orthographic
Stereographic
LambertEqualArea
Gnomonic
AzimuthalEquidistant
Satellite
Mollweide
Mercator
CylindricalEquidistant
LambertConformal
NPC
NPC
limits the area based on "Normalized Projection
Coordinates," which map the maximal area of the projection into a
rectangle bounded by 0.0 and 1.0 horizontally and vertically. Use the
resources mpLeftNPCF, mpRightNPCF, mpBottomNPCF, and mpTopNPCF to set
normalized projection coordinate limits. If you set NPC boundaries
such that the resulting area has zero extent,
MapTransformation issues a warning and resets
mpLimitMode to the value NhlMAXIMALAREA. If you set
mpLeftNPCF to a value greater than mpRightNPCF or
mpBottomNPCF to a value greater than mpTopNPCF,
MapTransformation issues a warning and exchanges the
values. MapTransformation keeps the NPC resources
updated to their current value no matter which method is used to set
the map limits.
NDC
NDC
limits the area based on the current location of
the projected map in Normalized Device Coordinates. Use the resources
mpLeftNDCF, mpRightNDCF, mpBottomNDCF, and mpTopNDCF to set
normalized device coordinate limits. If you set NDC boundaries such
that the resulting area has zero extent, MapTransformation
issues a warning and resets mpLimitMode to the value
NhlMAXIMALAREA. If you set mpLeftNDCF to a value greater than
mpRightNDCF or mpBottomNDCF to a value greater than
mpTopNDCF, MapTransformation issues a warning and
exchanges the values. Note that setting these resources usually causes
the mapping between the projection space and NDC space to
change. Changes to the location of the size or shape of the viewport
into which the map is projected also modify the mapping into NDC
space. Therefore, at the completion of each
SetValues call, MapTransformation
internally sets the value of each mp...NDCF resource to the
new location of the original projected coordinate: that is, to one of
the boundaries of the projected area.
Corners
MaximalArea
.
Points
MaximalArea
mode.
Window
Window
resources updated to their current value no matter which method is
used to set the map limits.
Default: MaximalArea
LatLon
, this
resource specifies the minimum latitude bounding the area to be mapped
to the viewport. It should not be less than -90.0.
Default: -90.0
LatLon
, this
resource specifies the maximum latitude bounding the area to be mapped
to the viewport. It should not be greater than 90.0.
Default: 90.0
LatLon
, this
resource specifies the minimum longitude bounding the area to be
mapped to the viewport. It may be set to any value in the range -540.0 to
540.0 such that mpMaxLonF minus mpMinLonF is greater
than 0.0 and less than or equal to 360.0.
Default: -180.0
LatLon
, this
resource specifies the maximum longitude bounding the area to be
mapped to the viewport. It may be set to any value in the range -540.0 to
540.0 such that mpMaxLonF minus mpMinLonF is greater
than 0.0 and less than or equal to 360.0.
Default: 180.0
LatLon
and
mpRelativeCenterLon is set True, the resource
mpCenterLonF becomes an offset in degrees from the longitude
halfway between mpMinLonF and mpMaxLonF. That is, if
mpCenterLonF is 0.0, the half point longitude will be the
center of the projection.
Default: False
LatLon
and
mpRelativeCenterLat is set True, the resource
mpCenterLatF becomes an offset in degrees from the latitude
halfway between mpMinLatF and mpMaxLatF. That is, if
mpCenterLatF is 0.0, the half point latitude will be the
center of the projection.
Default: False
Angles
, this resource
specifies the positive angle in degrees left from the center to the
edge of the projection, or, if using a satellite projection, the
displacement angle left from the satellite line of sight to the
projection center. Note that direction of the line over which the
angle is measured remains parallel to the top of the viewport,
regardless of the rotation angle applied to the
projection. mpLeftAngleF has a maximum allowable value that varies
depending on the projection.
Default: 80.0
Angles
, this
resource specifies the positive angle in degrees right from the center
to the edge of the projection, or, if using a satellite projection,
the displacement angle right from the satellite line of sight to the
projection center. Note that direction of the line over which the
angle is measured remains parallel to the top of the viewport,
regardless of the rotation angle applied to the
projection. mpRightAngleF has a maximum allowable value that
varies depending on the projection.
Default: 80.0
Angles
, this
resource specifies the positive angle in degrees down from the center
to the edge of the projection, or, if using a satellite projection,
the displacement angle down from the satellite line of sight to the
projection center. Note that direction of the line over which the
angle is measured remains parallel to the left edge of the viewport,
regardless of the rotation angle applied to the
projection. mpBottomAngleF has a maximum allowable value that
varies depending on the projection.
Default: 80.0
Angles
, this
resource specifies the positive angle in degrees up from the center to
the edge of the projection, or, if using a satellite projection, the
displacement angle up from the satellite line of sight to the
projection center. Note that direction of the line over which the
angle is measured remains parallel to the left edge of the viewport,
regardless of the rotation angle applied to the
projection. mpTopAngleF has a maximum allowable value that
varies depending on the projection.
Default: 80.0
NPC
, this resource
specifies the left edge of the limiting rectangle in Normalized
Projection Coordinates. mpLeftNPCF is constrained to values
in the range 0.0 through 1.0. If mpLeftNPCF is set to a value
greater than mpRightNPCF, a warning is issued and the values
are exchanged. The value of mpLeftNPCF is updated whenever
the map limits are set using any of the map limit modes.
Default: 0.0
NPC
, this resource
specifies the right edge of the limiting rectangle in Normalized
Projection Coordinates. mpRightNPCF is constrained to values
in the range 0.0 through 1.0. If mpRightNPCF is set to a value
less than mpLeftNPCF, a warning is issued and the values
are exchanged. The value of mpRightNPCF is updated whenever
the map limits are set using any of the map limit modes.
Default: 1.0
NPC
, this resource
specifies the bottom edge of the limiting rectangle in Normalized
Projection Coordinates. mpBottomNPCF is constrained to values
in the range 0.0 through 1.0. If mpBottomNPCF is set to a value
greater than mpTopNPCF, a warning is issued and the values
are exchanged. The value of mpBottomNPCF is updated whenever
the map limits are set using any of the map limit modes.
Default: 0.0
NPC
, this resource
specifies the top edge of the limiting rectangle in Normalized
Projection Coordinates. mpTopNPCF is constrained to values
in the range 0.0 through 1.0. If mpTopNPCF is set to a value
less than mpBottomNPCF, a warning is issued and the values
are exchanged. The value of mpTopNPCF is updated whenever
the map limits are set using any of the map limit modes.
Default: 1.0
NDC
, this
resource specifies the left edge of the limiting rectangle in
Normalized Device Coordinates. If mpLeftNDCF is set to a
value greater than mpRightNDCF, a warning is issued and the
values are exchanged. Since the relationship between the map
projection area and NDC coordinates changes whenever the map limits
are changed, as well as when the viewport area is moved or resized,
MapTransformation resets the value of
mpLeftNDCF to the NDC value of the left edge of the projected
area at the end of any update to the transformation.
Default: <dynamic>
NDC
, this
resource specifies the right edge of the limiting rectangle in
Normalized Device Coordinates. If mpRightNDCF is set to a
value less than mpLeftNDCF, a warning is issued and the values
are exchanged. Since the relationship between the map projection area
and NDC coordinates changes whenever the map limits are changed, as
well as when the viewport area is moved or resized,
MapTransformation resets the value of mpRightNDCF
to the NDC value of the right edge of the projected area at the end of
any update to the transformation.
Default: <dynamic>
NDC
, this
resource specifies the bottom edge of the limiting rectangle in
Normalized Device Coordinates. If mpBottomNDCF is set to a
value greater than mpRightNDCF, a warning is issued and the values
are exchanged. Since the relationship between the map projection area
and NDC coordinates changes whenever the map limits are changed, as
well as when the viewport area is moved or resized,
MapTransformation resets the value of mpBottomNDCF
to the NDC value of the bottom edge of the projected area at the end of
any update to the transformation.
Default: <dynamic>
NDC
, this
resource specifies the top edge of the limiting rectangle in
Normalized Device Coordinates. If mpTopNDCF is set to a
value less than mpBottomNDCF, a warning is issued and the values
are exchanged. Since the relationship between the map projection area
and NDC coordinates changes whenever the map limits are changed, as
well as when the viewport area is moved or resized,
MapTransformation resets the value of mpTopNDCF
to the NDC value of the top edge of the projected area at the end of
any update to the transformation.
Default: <dynamic>
Corners
, this resource
specifies the latitude, in degrees, of the left corner point.
Default: 0.0
Corners
, this resource
specifies the longitude, in degrees, of the left corner point.
Default: 0.0
Corners
, this resource
specifies the latitude, in degrees, of the right corner point.
Default: 0.0
Corners
, this resource
specifies the longitude, in degrees, of the right corner point.
Default: 0.0
Points
, this resource
specifies the latitude, in degrees, of a point along the left edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the longitude, in degrees, of a point along the left edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the latitude, in degrees, of a point along the right edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the longitude, in degrees, of a point along the right edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the latitude, in degrees, of a point along the bottom edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the longitude, in degrees, of a point along the bottom edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the latitude, in degrees, of a point along the top edge of
the limiting rectangle.
Default: 0.0
Points
, this resource
specifies the longitude, in degrees, of a point along the top edge of
the limiting rectangle.
Default: 0.0
Window
, this resource
specifies the value, in window coordinates, of the left edge of the
projection.
Default: 0.0
Window
, this resource
specifies the value, in window coordinates, of the right edge of the
projection.
Default: 0.0
Window
, this resource
specifies the value, in window coordinates, of the bottom edge of the
projection.
Default: 0.0
Window
, this resource
specifies the value, in window coordinates, of the top edge of the
projection.
Default: 0.0
LambertConformal
,
this resource specifies one of the two standard parallels (lines of
latitude in degrees) used to define the conic projection. A simpler conic
projection is defined when mpLambertParallel1F and
mpLambertParallel2F are equal. Normally,
mpLambertParallel1F and mpLambertParallel2F should not
be more than 90.0 degrees apart.
Default: .001
LambertConformal
,
this resource specifies one of the two standard parallels (lines of
latitude in degrees) used to define the conic projection. A simpler conic
projection is defined when mpLambertParallel1F and
mpLambertParallel2F are equal. Normally,
mpLambertParallel1F and mpLambertParallel2F should not
be more than 90.0 degrees apart.
Default: 89.999
LambertConformal
,
this resource specifies the central meridian (line of longitude in degrees)
of the projection. This resource has nearly the same meaning that
mpCenterLonF has for the other projections.
Default: 0.0
Satellite
, this resource
specifies the distance in multiples of the earth's radius of the
satellite at the view origin. If the value is 1.0 or less, the
satellite projection is replaced by its limiting case: an
orthographic projection.
Default: 1.0
Satellite
and
mpSatelliteDistF has a value greater than 1.0, this resource
specifies the angle in degrees between a line to the center of the
earth and the line of sight (to which the projection plane is
perpendicular).
Default: 0.0
Satellite
, mpSatelliteDistF has a value greater than 1.0,
and mpSatelliteAngle1F has a non-zero value. Imagine a
compass (the geometrical instrument) with its joint at the position of
the satellite, its first leg extending to the center of the earth, and
the second pointing in the direction of the line of sight. The second
leg is longer than the first, so that it meets a plane through the
center of the earth normal to the first leg. The angle in degrees
between the two legs is SatelliteAngle1F. When
SatelliteAngle2F has the value 0.0, a line drawn from the
first leg of the compass to the second will appear horizontal and
directed toward the right. Increasing values of
SatelliteAngle2F correspond to counterclockwise rotations of
the compass, (and hence, the line of sight) from this base position.
Default: 0.0
Default: False
CylindricalEquidistant
. Another characteristic of this
method is that, for any projection, a line between two points at the
same latitude is coincident with the line of latitude itself.
If mpGreatCircleLinesOn is set True, lines between defined points follow a great circle route, the shortest distance on the surface of the globe between the two points. In this case, lines appear curved on a cylindrical equidistant projection, except for the special cases of lines between points of equal longitude or of lines drawn near the equator. For any projection, lines between points of equal latitude diverge farther and farther from the line of latitude as the distance from the equator increases.
Default: False
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