gdal 0.19.0

GDAL bindings for Rust
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218

use std::{
    ffi::{c_char, c_void, CString},
    ptr::null_mut,
};

use gdal_sys::OGRErr;

use crate::errors::GdalError;
use crate::errors::Result;
use crate::utils::{_last_null_pointer_err, _string};
use crate::vector::Geometry;

/// Methods supporting translation between GDAL [`Geometry`] and various text representations.
///
/// These include:
/// * ["Well Known" representations of geometry][wikipedia].
/// * [GeoJSON][geojson]
///
/// [wikipedia]: https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry
/// [geojson]: https://geojson.org/
///
impl Geometry {
    /// Create a geometry by parsing a
    /// [WKT](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry) string.
    pub fn from_wkt(wkt: &str) -> Result<Geometry> {
        let c_wkt = CString::new(wkt)?;
        // OGR_G_CreateFromWkt does not write to the pointed-to memory, but this is not reflected
        // in its signature (`char**` instead of `char const**`), so we need a scary looking cast.
        let mut c_wkt_ptr = c_wkt.as_ptr() as *mut c_char;
        let mut c_geom = null_mut();
        let rv = unsafe { gdal_sys::OGR_G_CreateFromWkt(&mut c_wkt_ptr, null_mut(), &mut c_geom) };
        if rv != OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_CreateFromWkt",
            });
        }
        Ok(unsafe { Geometry::with_c_geometry(c_geom, true) })
    }

    /// Creates a geometry by parsing a slice of bytes in
    /// [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary)
    /// (Well-Known Binary) format.
    pub fn from_wkb(wkb: &[u8]) -> Result<Geometry> {
        let mut c_geom = null_mut();
        let rv = unsafe {
            gdal_sys::OGR_G_CreateFromWkb(
                wkb.as_ptr() as *const std::ffi::c_void,
                null_mut(),
                &mut c_geom,
                wkb.len() as i32,
            )
        };
        if rv != gdal_sys::OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_CreateFromWkb",
            });
        }
        Ok(unsafe { Geometry::with_c_geometry(c_geom, true) })
    }

    /// Create a geometry by parsing a
    /// [GeoJSON](https://en.wikipedia.org/wiki/GeoJSON) string.
    pub fn from_geojson(json: &str) -> Result<Geometry> {
        let c_geojson = CString::new(json)?;
        let c_geom = unsafe { gdal_sys::OGR_G_CreateGeometryFromJson(c_geojson.as_ptr()) };
        if c_geom.is_null() {
            return Err(_last_null_pointer_err("OGR_G_CreateGeometryFromJson"));
        }
        Ok(unsafe { Geometry::with_c_geometry(c_geom, true) })
    }

    /// Create a geometry by parsing a
    /// [GML](https://en.wikipedia.org/wiki/Geography_Markup_Language) string.
    pub fn from_gml(json: &str) -> Result<Geometry> {
        let c_gml = CString::new(json)?;
        let c_geom = unsafe { gdal_sys::OGR_G_CreateFromGML(c_gml.as_ptr()) };
        if c_geom.is_null() {
            return Err(_last_null_pointer_err("OGR_G_CreateFromGML"));
        }
        Ok(unsafe { Geometry::with_c_geometry(c_geom, true) })
    }

    /// Serialize the geometry as WKT.
    pub fn wkt(&self) -> Result<String> {
        let mut c_wkt = null_mut();
        let rv = unsafe { gdal_sys::OGR_G_ExportToWkt(self.c_geometry(), &mut c_wkt) };
        if rv != OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_ExportToWkt",
            });
        }
        let wkt = _string(c_wkt).unwrap_or_default();
        unsafe { gdal_sys::VSIFree(c_wkt as *mut c_void) };
        Ok(wkt)
    }

    /// Serialize the geometry as SFSQL 1.2 / ISO SQL / MM Part 3 WKT.
    pub fn iso_wkt(&self) -> Result<String> {
        let mut c_wkt = null_mut();
        let rv = unsafe { gdal_sys::OGR_G_ExportToIsoWkt(self.c_geometry(), &mut c_wkt) };
        if rv != OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_ExportToIsoWkt",
            });
        }
        let wkt = _string(c_wkt).unwrap_or_default();
        unsafe { gdal_sys::VSIFree(c_wkt as *mut c_void) };
        Ok(wkt)
    }

    /// Serializes the geometry to
    /// [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary)
    /// (Well-Known Binary) format.
    pub fn wkb(&self) -> Result<Vec<u8>> {
        let wkb_size = unsafe { gdal_sys::OGR_G_WkbSize(self.c_geometry()) as usize };
        // We default to little-endian for now. A WKB string explicitly indicates the byte
        // order, so this is not a problem for interoperability.
        //
        // Consider using `Vec::MaybeUninit` in future.
        let byte_order = gdal_sys::OGRwkbByteOrder::wkbNDR;
        let mut wkb = vec![0; wkb_size];
        let rv =
            unsafe { gdal_sys::OGR_G_ExportToWkb(self.c_geometry(), byte_order, wkb.as_mut_ptr()) };
        if rv != gdal_sys::OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_ExportToWkb",
            });
        }
        Ok(wkb)
    }

    /// Serializes the geometry to SFSQL 1.2 / ISO SQL / MM Part 3
    /// [WKB](https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry#Well-known_binary)
    /// (Well-Known Binary) format.
    pub fn iso_wkb(&self) -> Result<Vec<u8>> {
        let wkb_size = unsafe { gdal_sys::OGR_G_WkbSize(self.c_geometry()) as usize };
        // We default to little-endian for now. A WKB string explicitly indicates the byte
        // order, so this is not a problem for interoperability.
        //
        // Consider using `Vec::MaybeUninit` in future.
        let byte_order = gdal_sys::OGRwkbByteOrder::wkbNDR;
        let mut wkb = vec![0; wkb_size];
        let rv = unsafe {
            gdal_sys::OGR_G_ExportToIsoWkb(self.c_geometry(), byte_order, wkb.as_mut_ptr())
        };
        if rv != gdal_sys::OGRErr::OGRERR_NONE {
            return Err(GdalError::OgrError {
                err: rv,
                method_name: "OGR_G_ExportToIsoWkb",
            });
        }
        Ok(wkb)
    }

    /// Serialize the geometry as GeoJSON.
    ///
    /// See: [`OGR_G_ExportToJson`](https://gdal.org/api/vector_c_api.html#_CPPv418OGR_G_ExportToJson12OGRGeometryH)
    pub fn json(&self) -> Result<String> {
        let c_json = unsafe { gdal_sys::OGR_G_ExportToJson(self.c_geometry()) };
        let rv = _string(c_json).ok_or_else(|| _last_null_pointer_err("OGR_G_ExportToJson"));
        unsafe { gdal_sys::VSIFree(c_json as *mut c_void) };
        rv
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    pub fn test_wkb() {
        let wkt = "POLYGON ((45.0 45.0, 45.0 50.0, 50.0 50.0, 50.0 45.0, 45.0 45.0))";
        let orig_geom = Geometry::from_wkt(wkt).unwrap();
        let wkb = orig_geom.wkb().unwrap();
        let new_geom = Geometry::from_wkb(&wkb).unwrap();
        assert_eq!(new_geom, orig_geom);
    }

    #[test]
    pub fn test_iso_wkb() {
        let wkt = "POLYGON ZM ((45.0 45.0 0.0 0.0, 45.0 50.0 0.0 0.25, 50.0 50.0 0.0 0.50, 50.0 45.0 0.0 0.75, 45.0 45.0 0.0 1.0))";
        let orig_geom = Geometry::from_wkt(wkt).unwrap();
        let wkb = orig_geom.iso_wkb().unwrap();
        let new_geom = Geometry::from_wkb(&wkb).unwrap();
        assert_eq!(new_geom, orig_geom);
    }

    #[test]
    pub fn test_geojson() {
        let json = r#"{ "type": "Point", "coordinates": [10, 20] }"#;
        let geom = Geometry::from_geojson(json).unwrap();
        let (x, y, _) = geom.get_point(0);
        assert_eq!(x, 10.0);
        assert_eq!(y, 20.0);

        let json = r#"{ "type": "Point", "coordinates": [10, 20 }"#;
        let res = Geometry::from_geojson(json);
        assert!(res.is_err());
    }

    #[test]
    pub fn test_gml() {
        let json = r#"<gml:Point xmlns:gml="http://www.opengis.net/gml"><gml:coordinates>10,20</gml:coordinates></gml:Point>"#;
        let geom = Geometry::from_gml(json).unwrap();
        let (x, y, _) = geom.get_point(0);
        assert_eq!(x, 10.0);
        assert_eq!(y, 20.0);

        let json = r#"<gml:Point xmlns:gml="http://www.opengis.net/gml"><gml:coordinates>10</gml:coordinates></gml:Point>"#;
        let res = Geometry::from_gml(json);
        assert!(res.is_err());
    }
}