// Searches the R-Tree to find the place corresponding to the given lat,lng
// First uses the R-Tree which contains only the bounding boxes of the
// entities, and then refine the result using the actual geometry of the entity.
func reverseGeocode(rt *rtreego.Rtree, lat, lng, precision float64) (*GeoData, error) {
var results []rtreego.Spatial
// First search the R-Tree
rpt := rtreego.Point{lng, lat}
results = rt.SearchIntersect(rpt.ToRect(precision / 2.))
if len(results) == 0 || results[0] == nil {
nn := rt.NearestNeighbor(rpt)
if nn == nil {
return nil, ErrNoMatchFound
} else {
results = []rtreego.Spatial{nn}
}
}
// Then check with the actual geometry of the entity
mindist := math.MaxFloat64
var argmindist *GeoData
gpt, _ := geos.NewPoint(geos.NewCoord(lng, lat))
for _, res := range results {
if res == nil {
break
}
obj, _ := res.(SpatialData)
geod := obj.GetData()
inside, _ := geod.Geom.Contains(gpt)
if inside {
return geod, nil
}
dist, _ := gpt.Distance(geod.Geom)
if dist < mindist {
mindist = dist
argmindist = geod
}
}
if mindist < precision {
return argmindist, nil
}
return nil, ErrNoMatchFound
}
// Loads a CSV file from https://github.com/delight-im/FreeGeoDB
// The expected CSV columns are:
// 0 : id
// 1 : coordinates_wkt
// 2 : sovereign
// 3 : name
// 4 : formal
// 5 : economy_level
// 6 : income_level
// 7 : iso_alpha2
// 8 : iso_alpha3
// 9 : iso_numeric3
// 10 : continent
// 11 : subregion
func load_freegeodb_countries_csv(rt *rtreego.Rtree, fname string) (int, error) {
log.Println("Loading", fname, "...")
f, err := os.Open(fname)
if err != nil {
return 0, err
}
defer f.Close()
df, err := Decompressor(f)
if err != nil {
return 0, err
}
r := csv.NewReader(df)
r.Comma = ','
_, err = r.Read() // Don't read header
if err != nil {
return 0, err
}
line := 0
loaded_objects := 0
for {
cols, err := r.Read()
if err == io.EOF {
break
} else if err != nil {
return loaded_objects, err
}
line++
if len(cols) != 12 {
return loaded_objects, fmt.Errorf("Invalid column format in", fname, cols)
}
if len(cols[7]) != 2 || len(cols[8]) != 3 || len(cols[3]) == 0 {
continue
}
geodb_id, err := strconv.ParseInt(cols[0], 10, 64)
if err != nil {
log.Fatal("Error parsing", cols, line, err)
}
geom, err := geos.FromWKT(cols[1])
if err != nil {
log.Fatal("Error parsing", cols, line, err)
}
rect, err := RtreeBboxg(geom, 1e-5)
if err != nil {
log.Fatal("Error getting bbox", cols, line, err)
}
obj := GeoObj{rect,
&GeoData{
Id: geodb_id,
CountryName: cols[3],
CountryCode_2: cols[7],
CountryCode_3: cols[8],
Type: "country",
Geom: geom}}
rt.Insert(&obj)
loaded_objects++
}
return loaded_objects, nil
}
// Loads a CSV file from http://download.gisgraphy.com/openstreetmap/csv/cities/
// The expected CSV columns are:
// 0 : Node type; N|W|R (in uppercase), wheter it is a Node, Way or Relation in the openstreetmap Model
// 1 : id; The openstreetmap id
// 2 : name; the default name of the city
// 3 : countrycode; The iso3166-2 country code (2 letters)
// 4 : postcode; The postcode / zipcode / ons code / municipality code / ...
// 5 : population; How many people lives in that city
// 6 : location; The middle location of the city in HEXEWKB
// 7 : shape; The delimitation of the city in HEXEWKB
// 8 : type; the type of city ('city', 'village', 'town', 'hamlet', ...)
// 9 : is_in ; where the cities is located (generally the fully qualified administrative division)
// 10 : alternatenames; the names of the city in other languages
func load_gisgraphy_cities_csv(rt *rtreego.Rtree, fname string) (int, error) {
log.Println("Loading", fname, "...")
f, err := os.Open(fname)
if err != nil {
return 0, err
}
defer f.Close()
df, err := Decompressor(f)
if err != nil {
log.Fatal(err)
}
var r *csv.Reader
if strings.Contains(fname, ".tar.") {
// Handles uncompressed files downloaded from gisgraphy.com
tf := tar.NewReader(df)
for {
hdr, err := tf.Next()
if err == io.EOF {
log.Fatal("Couldn't find CSV file in " + fname)
} else if err != nil {
log.Fatal(err)
}
if strings.HasSuffix(hdr.Name, ".txt") {
r = csv.NewReader(tf)
break
}
}
} else {
// Handles unzipped files
r = csv.NewReader(df)
}
r.Comma = '\t'
line := 0
loaded_objects := 0
for {
cols, err := r.Read()
if err == io.EOF {
break
} else if err != nil {
return loaded_objects, err
}
line++
if len(cols[7]) == 0 {
continue
}
osm_id, err := strconv.ParseInt(cols[1], 10, 64)
if err != nil {
log.Fatal("Error parsing", cols, line, err)
}
geom, err := geos.FromHex(cols[7])
if err != nil {
log.Fatal("Error parsing", cols, line, err)
}
rect, err := RtreeBboxg(geom, 1e-5)
if err != nil {
log.Fatal("Error getting bbox", cols, line, err)
}
obj := GeoObj{rect,
&GeoData{
Id: osm_id,
City: cols[2],
CountryCode_2: cols[3],
Type: "city",
Geom: geom}}
rt.Insert(&obj)
loaded_objects++
}
return loaded_objects, nil
}