Extend the existing possibilities of writing ogr datasets. #31
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,53 @@ | ||
| extern crate gdal; | ||
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| use std::fs; | ||
| use std::path::Path; | ||
| use gdal::vector::*; | ||
| use gdal::spatial_ref::{SpatialRef, CoordTransform}; | ||
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| fn main() { | ||
| let mut dataset_a = Dataset::open(Path::new("fixtures/roads.geojson")).unwrap(); | ||
| let layer_a = dataset_a.layer(0).unwrap(); | ||
| let fields_defn = layer_a.defn().fields() | ||
| .map(|field| (field.name(), field.get_type(), field.get_width())) | ||
| .collect::<Vec<_>>(); | ||
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| // Create a new dataset : | ||
| fs::remove_file("/tmp/abcde.shp"); | ||
| let drv = Driver::get("ESRI Shapefile").unwrap(); | ||
| let mut ds = drv.create(Path::new("/tmp/abcde.shp")).unwrap(); | ||
| let lyr = ds.create_layer().unwrap(); | ||
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| // Copy the origin layer shema to the destination layer : | ||
| for fd in &fields_defn { | ||
| let field_defn = FieldDefn::new(&fd.0, fd.1); | ||
| field_defn.set_width(fd.2); | ||
| field_defn.add_to_layer(&lyr); | ||
| } | ||
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| // Prepare the origin and destination spatial references objects : | ||
| let spatial_ref_src = SpatialRef::from_epsg(4326).unwrap(); | ||
| let spatial_ref_dst = SpatialRef::from_epsg(3025).unwrap(); | ||
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| // And the feature used to actually transform the geometries : | ||
| let htransform = CoordTransform::new(&spatial_ref_src, &spatial_ref_dst).unwrap(); | ||
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| // Get the definition to use on each feature : | ||
| let defn = Defn::new_from_layer(&lyr); | ||
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| for feature_a in layer_a.features() { | ||
| // Get the original geometry : | ||
| let geom = feature_a.geometry(); | ||
| // Get a new transformed geometry : | ||
| let new_geom = geom.transform(&htransform).unwrap(); | ||
| // Create the new feature, set its geometry : | ||
| let mut ft = Feature::new(&defn); | ||
| ft.set_geometry(new_geom); | ||
| // copy each field value of the feature : | ||
| for fd in &fields_defn { | ||
| ft.set_field(&fd.0, fd.1, feature_a.field(&fd.0).unwrap()) | ||
| } | ||
| // Add the feature to the layer : | ||
| ft.create(&lyr); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,80 @@ | ||
| extern crate gdal; | ||
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| use std::path::Path; | ||
| use std::fs; | ||
| use gdal::vector::{Defn, Driver, Feature, FieldDefn, Geometry, OFT_INTEGER, OFT_REAL, OFT_STRING, FieldValue}; | ||
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| fn main(){ | ||
| /// Example 1, the detailed way : | ||
| { | ||
| fs::remove_file("/tmp/output1.geojson"); | ||
| let drv = Driver::get("GeoJSON").unwrap(); | ||
| let mut ds = drv.create(Path::new("/tmp/output1.geojson")).unwrap(); | ||
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| let lyr = ds.create_layer().unwrap(); | ||
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| let field_defn = FieldDefn::new("Name", OFT_STRING); | ||
| field_defn.set_width(80); | ||
| field_defn.add_to_layer(&lyr); | ||
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| let field_defn = FieldDefn::new("Value", OFT_REAL); | ||
| field_defn.add_to_layer(&lyr); | ||
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| let defn = Defn::new_from_layer(&lyr); | ||
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| // 1st feature : | ||
| let mut ft = Feature::new(&defn); | ||
| ft.set_geometry(Geometry::from_wkt("POINT (45.21 21.76)").unwrap()); | ||
| ft.set_field_string("Name", "Feature 1"); | ||
| ft.set_field_double("Value", 45.78); | ||
| ft.create(&lyr); | ||
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| // 2nd feature : | ||
| let mut ft = Feature::new(&defn); | ||
| ft.set_geometry(Geometry::from_wkt("POINT (46.50 22.50)").unwrap()); | ||
| ft.set_field_string("Name", "Feature 2"); | ||
| ft.set_field_double("Value", 0.789); | ||
| ft.create(&lyr); | ||
| } | ||
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| /// Example 2, same output, shortened way : | ||
| { | ||
| fs::remove_file("/tmp/output2.geojson"); | ||
| let driver = Driver::get("GeoJSON").unwrap(); | ||
| let mut ds = driver.create(Path::new("/tmp/output2.geojson")).unwrap(); | ||
| let mut layer = ds.create_layer().unwrap(); | ||
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| layer.create_defn_fields(&[("Name", OFT_STRING), ("Value", OFT_REAL)]); | ||
| // Shortcut for : | ||
| // let field_defn = FieldDefn::new("Name", OFT_STRING); | ||
| // field_defn.add_to_layer(&layer); | ||
| // let field_defn = FieldDefn::new("Value", OFT_REAL); | ||
| // field_defn.add_to_layer(&layer); | ||
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| layer.create_feature_fields( | ||
| Geometry::from_wkt("POINT (45.21 21.76)").unwrap(), | ||
| &["Name", "Value"], | ||
| &[FieldValue::StringValue("Feature 1".to_string()), FieldValue::RealValue(45.78)] | ||
| ); | ||
| layer.create_feature_fields( | ||
| Geometry::from_wkt("POINT (46.50 22.50)").unwrap(), | ||
| &["Name", "Value"], | ||
| &[FieldValue::StringValue("Feature 2".to_string()), FieldValue::RealValue(0.789)] | ||
| ); | ||
| // Shortcuts for : | ||
| // let defn = Defn::new_from_layer(&layer); | ||
| // | ||
| // let mut ft = Feature::new(&defn); | ||
| // ft.set_geometry(Geometry::from_wkt("POINT (45.21 21.76)").unwrap()); | ||
| // ft.set_field("Name", OFT_STRING, "Feature 1"); | ||
| // ft.set_field("Value", OFT_REAL, 45.78); | ||
| // ft.create(&lyr); | ||
| // | ||
| // let mut ft = Feature::new(&defn); | ||
| // ft.set_geometry(Geometry::from_wkt("POINT (46.50 22.50)").unwrap()); | ||
| // ft.set_field("Name", OFT_STRING, "Feature 2"); | ||
| // ft.set_field("Value", OFT_REAL, 0.789); | ||
| // ft.create(&lyr); | ||
| } | ||
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| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,10 +1,13 @@ | ||
| use std::ffi::CString; | ||
| use libc::{c_void, c_double, c_int}; | ||
| use vector::Defn; | ||
| use utils::_string; | ||
| use gdal_sys::{ogr, ogr_enums}; | ||
| use vector::geometry::Geometry; | ||
| use vector::layer::Layer; | ||
| use gdal_major_object::MajorObject; | ||
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| use errors::*; | ||
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| /// OGR Feature | ||
| pub struct Feature<'a> { | ||
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@@ -15,6 +18,15 @@ pub struct Feature<'a> { | |
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| impl<'a> Feature<'a> { | ||
| pub fn new(defn: &'a Defn) -> Feature { | ||
| let c_feature = unsafe { ogr::OGR_F_Create(defn.c_defn()) }; | ||
| unsafe { Feature { | ||
| _defn: defn, | ||
| c_feature: c_feature, | ||
| geometry: Geometry::lazy_feature_geometry(), | ||
| } } | ||
| } | ||
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| pub unsafe fn _with_c_feature(defn: &'a Defn, c_feature: *const c_void) -> Feature { | ||
| return Feature{ | ||
| _defn: defn, | ||
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@@ -43,6 +55,10 @@ impl<'a> Feature<'a> { | |
| let rv = unsafe { ogr::OGR_F_GetFieldAsDouble(self.c_feature, field_id) }; | ||
| return Some(FieldValue::RealValue(rv as f64)); | ||
| }, | ||
| ogr::OFT_INTEGER => { | ||
| let rv = unsafe { ogr::OGR_F_GetFieldAsInteger(self.c_feature, field_id) }; | ||
| return Some(FieldValue::IntegerValue(rv as i32)); | ||
| }, | ||
| _ => panic!("Unknown field type {}", field_type) | ||
| } | ||
| } | ||
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@@ -55,6 +71,52 @@ impl<'a> Feature<'a> { | |
| } | ||
| return &self.geometry; | ||
| } | ||
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| pub fn create(&self, lyr: &Layer) -> Result<()> { | ||
| let rv = unsafe { ogr::OGR_L_CreateFeature(lyr.gdal_object_ptr(), self.c_feature) }; | ||
| if rv != ogr_enums::OGRErr::OGRERR_NONE { | ||
| return Err(ErrorKind::OgrError(rv, "OGR_L_CreateFeature").into()); | ||
| } | ||
| Ok(()) | ||
| } | ||
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| pub fn set_field_string(&self, field_name: &str, value: &str){ | ||
| let c_str_field_name = CString::new(field_name).unwrap(); | ||
|
There was a problem hiding this comment. If it is possible please try not to use There was a problem hiding this comment. Alright for returning There was a problem hiding this comment. Error handling in rust is a bit difficult. Where is a lot about it in the book. To make this easier rust-gdal uses the error-chain crate. We already have some wrapping errors in errors.rs: To handle the |
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| let c_str_value = CString::new(value).unwrap(); | ||
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There was a problem hiding this comment.
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| let idx = unsafe { ogr::OGR_F_GetFieldIndex(self.c_feature, c_str_field_name.as_ptr())}; | ||
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There was a problem hiding this comment.
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| unsafe { ogr::OGR_F_SetFieldString(self.c_feature, idx, c_str_value.as_ptr()) }; | ||
| } | ||
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| pub fn set_field_double(&self, field_name: &str, value: f64){ | ||
| let c_str_field_name = CString::new(field_name).unwrap(); | ||
| let idx = unsafe { ogr::OGR_F_GetFieldIndex(self.c_feature, c_str_field_name.as_ptr())}; | ||
| unsafe { ogr::OGR_F_SetFieldDouble(self.c_feature, idx, value as c_double) }; | ||
| } | ||
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| pub fn set_field_integer(&self, field_name: &str, value: i32){ | ||
| let c_str_field_name = CString::new(field_name).unwrap(); | ||
| let idx = unsafe { ogr::OGR_F_GetFieldIndex(self.c_feature, c_str_field_name.as_ptr())}; | ||
| unsafe { ogr::OGR_F_SetFieldInteger(self.c_feature, idx, value as c_int) }; | ||
| } | ||
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| pub fn set_field(&self, field_name: &str, type_value: i32, value: FieldValue){ | ||
| if type_value == 2 { | ||
| self.set_field_double(field_name, value.as_real()); | ||
| } else if type_value == 4 { | ||
| self.set_field_string(field_name, value.as_string().as_str()); | ||
| } else if type_value == 0 { | ||
| self.set_field_integer(field_name, value.as_int()); | ||
| } | ||
| } | ||
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| pub fn set_geometry(&mut self, geom: Geometry) -> Result<()> { | ||
| self.geometry = geom; | ||
|
There was a problem hiding this comment. What happens if the following method call fails? Wouldn't it be more safe if this is done after the GDAL call and before |
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| let rv = unsafe { ogr::OGR_F_SetGeometry(self.c_feature, self.geometry.c_geometry()) }; | ||
| if rv != ogr_enums::OGRErr::OGRERR_NONE { | ||
| return Err(ErrorKind::OgrError(rv, "OGR_G_SetGeometry").into()); | ||
| } | ||
| Ok(()) | ||
| } | ||
| } | ||
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@@ -66,6 +128,7 @@ impl<'a> Drop for Feature<'a> { | |
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| pub enum FieldValue { | ||
| IntegerValue(i32), | ||
| StringValue(String), | ||
| RealValue(f64), | ||
| } | ||
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@@ -87,4 +150,12 @@ impl FieldValue { | |
| _ => panic!("not a RealValue") | ||
| } | ||
| } | ||
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| /// Interpret the value as `i32`. Panics if the value is something else. | ||
| pub fn as_int(self) -> i32 { | ||
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There was a problem hiding this comment. Methods that consume There was a problem hiding this comment. Should I also change the name of the two previous methods ( There was a problem hiding this comment. i guess this would be the right thing to do. Also i think these methods should return an Option instead of panicking... There was a problem hiding this comment. I made the other changes but not this last one (returning an pub fn set_field(&self, field_name: &str, type_value: OGRFieldType, value: FieldValue) -> Result<()> {
match type_value {
OGRFieldType::OFTReal => self.set_field_double(field_name, value.to_real()),like here, when using |
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| match self { | ||
| FieldValue::IntegerValue(rv) => rv, | ||
| _ => panic!("not an IntegerValue") | ||
| } | ||
| } | ||
| } | ||
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I think it would be nice to change the OFT types into an enum and move it into ogr_enums.rs. This way all the FFI methods could take OgrFieldType instead of c_int as parameter. (link to the OGR enum)
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I was thinking too about moving OFT types into an enum, so no problem, I will do it.