Add filters to opennames processing. Filter out suburban areas.

cmd/localtypes/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"sort"
+
+	"github.com/ray1729/gpx-utils/pkg/openname"
+)
+
+func main() {
+	log.SetFlags(0)
+	if len(os.Args) != 2 {
+		log.Fatal("Usage: %s OPNAME_CSV_ZIP", os.Args[0])
+	}
+	var records []*openname.Record
+	openname.ProcessFile(
+		os.Args[1],
+		func(r *openname.Record) error {
+			records = append(records, r)
+			return nil
+		},
+		openname.FilterType("populatedPlace"),
+		openname.FilterWithinRadius(544945, 258410, 20000),
+	)
+	sort.Slice(records, func(i, j int) bool {
+		return records[i].Name < records[j].Name
+	})
+	for _, r := range records {
+		fmt.Printf("%s,%s\n", r.Name, r.LocalType)
+	}
+}

cmd/save-gob/main.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	"encoding/gob"
 	"log"
 	"os"
 
 	"github.com/ray1729/gpx-utils/pkg/openname"
+	"github.com/ray1729/gpx-utils/pkg/placenames"
 )
 
 func main() {
@@ -12,7 +14,28 @@ func main() {
 	if len(os.Args) != 3 {
 		log.Fatal("Usage: %s INFILE OUTFILE", os.Args[0])
 	}
-	if err := openname.Save(os.Args[1], os.Args[2]); err != nil {
+	wc, err := os.OpenFile(os.Args[2], os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer wc.Close()
+	enc := gob.NewEncoder(wc)
+	err = openname.ProcessFile(
+		os.Args[1],
+		func(r *openname.Record) error {
+			b := placenames.NamedBoundary{
+				Name: r.Name,
+				Xmin: r.MbrXMin,
+				Ymin: r.MbrYMin,
+				Xmax: r.MbrXMax,
+				Ymax: r.MbrYMax}
+			return enc.Encode(b)
+		},
+		openname.FilterType("populatedPlace"),
+		openname.FilterLocalType("Suburban Area").Complement(),
+		openname.FilterAreaGt(0),
+	)
+	if err != nil {
 		log.Fatal(err)
 	}
 }

pkg/openname/io.go

@@ -2,16 +2,49 @@ package openname
 
 import (
 	"archive/zip"
-	"encoding/gob"
 	"fmt"
-	"os"
+	"math"
 	"strings"
-
-	"github.com/ray1729/gpx-utils/pkg/placenames"
 )
 
+type Handler func(*Record) error
+
+type Filter func(*Record) bool
+
+func (f Filter) Complement() Filter {
+	return func(r *Record) bool {
+		return !f(r)
+	}
+}
+
+func FilterType(t string) Filter {
+	return func(r *Record) bool {
+		return r.Type == t
+	}
+}
+
+func FilterLocalType(t string) Filter {
+	return func(r *Record) bool {
+		return r.LocalType == t
+	}
+}
+
+func FilterWithinRadius(x, y, radius float64) Filter {
+	return func(r *Record) bool {
+		dx := x - r.GeomX
+		dy := y - r.GeomY
+		return math.Sqrt(dx*dx+dy*dy) <= radius
+	}
+}
+
+func FilterAreaGt(a float64) Filter {
+	return func(r *Record) bool {
+		return r.Area() > a
+	}
+}
+
 // ProcessFile reads the compressed OS Open Names data set and calls the handler for each record.
-func ProcessFile(filename string, handler func(*Record) error) error {
+func ProcessFile(filename string, handler Handler, filters ...Filter) error {
 	r, err := zip.OpenReader(filename)
 	if err != nil {
 		return fmt.Errorf("error opening %s for reading: %v", filename, err)
@@ -33,12 +66,13 @@ func ProcessFile(filename string, handler func(*Record) error) error {
 		}
 		for s.Scan() {
 			r := s.Record()
-			if r.Type == "populatedPlace" && r.MbrXMax != r.MbrXMin && r.MbrYMax != r.MbrYMin {
+			if wanted := applyFilters(r, filters); !wanted {
+				continue
+			}
 			if err := handler(r); err != nil {
 				return err
 			}
 		}
-		}
 		if err = s.Err(); err != nil {
 			rc.Close()
 			return fmt.Errorf("error parsing %s: %v", f.Name, err)
@@ -48,22 +82,11 @@ func ProcessFile(filename string, handler func(*Record) error) error {
 	return nil
 }
 
-// Save processes the OS OpenNames zip file and outputs bounded places in gob format.
-func Save(inFile string, outFile string) error {
-	wc, err := os.OpenFile(outFile, os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0644)
-	if err != nil {
-		return err
+func applyFilters(r *Record, filters []Filter) bool {
+	for _, f := range filters {
+		if !f(r) {
+			return false
 		}
-	defer wc.Close()
-	enc := gob.NewEncoder(wc)
-	err = ProcessFile(inFile, func(r *Record) error {
-		b := placenames.NamedBoundary{
-			Name: r.Name,
-			Xmin: r.MbrXMin,
-			Ymin: r.MbrYMin,
-			Xmax: r.MbrXMax,
-			Ymax: r.MbrYMax}
-		return enc.Encode(b)
-	})
-	return err
+	}
+	return true
 }

pkg/openname/parse.go

@@ -56,6 +56,10 @@ func (r *Record) Bounds() *rtreego.Rect {
 	return rect
 }
 
+func (r *Record) Area() float64 {
+	return (r.MbrXMax - r.MbrXMin) * (r.MbrYMax - r.MbrYMin)
+}
+
 type Scanner struct {
 	csvReader  *csv.Reader
 	nextRecord *Record