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53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
// Copyright 2016, 2017 Florian Pigorsch. All rights reserved.
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//
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package sm
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import (
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"fmt"
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"math"
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"github.com/golang/geo/s1"
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"github.com/golang/geo/s2"
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)
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// CreateBBox creates a bounding box from a north-western point
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// (lat/lng in degrees) and a south-eastern point (lat/lng in degrees).
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// Note that you can create a bounding box wrapping over the antimeridian at
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// lng=+-/180° by nwlng > selng.
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func CreateBBox(nwlat float64, nwlng float64, selat float64, selng float64) (*s2.Rect, error) {
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if nwlat < -90 || nwlat > 90 {
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return nil, fmt.Errorf("Out of range nwlat (%f) must be in [-90, 90]", nwlat)
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}
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if nwlng < -180 || nwlng > 180 {
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return nil, fmt.Errorf("Out of range nwlng (%f) must be in [-180, 180]", nwlng)
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}
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if selat < -90 || selat > 90 {
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return nil, fmt.Errorf("Out of range selat (%f) must be in [-90, 90]", selat)
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}
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if selng < -180 || selng > 180 {
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return nil, fmt.Errorf("Out of range selng (%f) must be in [-180, 180]", selng)
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}
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if nwlat == selat {
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return nil, fmt.Errorf("nwlat and selat must not be equal")
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}
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if nwlng == selng {
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return nil, fmt.Errorf("nwlng and selng must not be equal")
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}
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bbox := new(s2.Rect)
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if selat < nwlat {
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bbox.Lat.Lo = selat * math.Pi / 180.0
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bbox.Lat.Hi = nwlat * math.Pi / 180.0
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} else {
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bbox.Lat.Lo = nwlat * math.Pi / 180.0
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bbox.Lat.Hi = selat * math.Pi / 180.0
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}
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bbox.Lng = s1.IntervalFromEndpoints(nwlng*math.Pi/180.0, selng*math.Pi/180.0)
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return bbox, nil
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}
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