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https://github.com/plechi/mini-geocoder
Minimal Geocoder and Geocoding REST-API you can run on your Server. Uses Openstreetmap data.
https://github.com/plechi/mini-geocoder
Last synced: 18 days ago
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Minimal Geocoder and Geocoding REST-API you can run on your Server. Uses Openstreetmap data.
- Host: GitHub
- URL: https://github.com/plechi/mini-geocoder
- Owner: plechi
- License: other
- Archived: true
- Created: 2015-05-01T18:37:10.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2017-03-23T18:38:50.000Z (over 7 years ago)
- Last Synced: 2024-08-01T00:45:56.351Z (3 months ago)
- Language: Java
- Homepage:
- Size: 16.6 KB
- Stars: 17
- Watchers: 4
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Minimal Geocoder
Minimal Geocoder is a simple Geocoding API based on data from Openstreetmap and a REST interface using Spring Framework.
Background information (in German): http://blog.plechinger.at/einfaches-geocoding-mit-open-street-map/.
## Example:
**Request**:
```
http://localhost:8080/geocode?q=hauptplatz+graz
```
**Response**:
```json
[
{
"street" : "Hauptplatz",
"housenumber" : "9",
"postcode" : "8010",
"city" : "Graz",
"country" : "AT",
"longitude" : 15.437595916666666,
"latitude" : 47.071199916666664
},
...
]
```
## Prerequisites
- Computer with Java >1.7
- Postgres Server with installed PostGis extension
Installation guide for PostGis: [http://postgis.net/install]()
## Installation
At first you have to create a new database and activate the extensions `hstore` and `postgis`
```sql
CREATE EXTENSION postgis;
CREATE EXTENSION hstore;
```
After that you need [Osmosis](http://wiki.openstreetmap.org/wiki/Osmosis) and a dataset from Openstreetmap from [here](http://wiki.openstreetmap.org/wiki/Downloading_data)
or [here](http://download.geofabrik.de/).
Create the database schema from Osmosis:
```bash
psql -d -f /script/pgsnapshot_schema_0.6.sql
```
Import the data:
```bash
osmosis --read-xml file="datafile.osm" --write-apidb host="localhost" database="" user="" password=""
```
With that configuration (and additional indices for the hstore columns), a single geocoding operation takes an average of 760ms, reverse geocoding up to 2600ms,
thats far to long. To speed things up, a optimized table should be created and this results in about 20 ms for geocoding and 120ms for reverse geocoding.
Performance improvements:
- precalculated Point for reverse geocoding
- preindexed full text search
- minimize calls of functions and subqueries
- no hstore queries
**Optimization table**: (you can also find the script in `optimize.sql`)
```sql
CREATE TABLE geocode_optimized
AS SELECT
w.tags -> 'addr:street' AS street,
w.tags -> 'addr:housenumber' AS housenumber,
w.tags -> 'addr:postcode' AS postcode,
w.tags -> 'addr:city' AS city,
w.tags -> 'addr:country' AS country,
AVG(ST_X(n.geom)) AS longitude,
AVG(ST_Y(n.geom)) AS latitude,
to_tsvector(concat_ws(' ', w.tags -> 'addr:street',
w.tags -> 'addr:housenumber',
w.tags -> 'addr:postcode',
w.tags -> 'addr:city',
w.tags -> 'addr:country'
)) AS full_text,
st_makepoint(AVG(ST_X(n.geom)), AVG(ST_Y(n.geom))) AS point
FROM ways w
INNER JOIN way_nodes wn ON w.id = wn.way_id
INNER JOIN nodes n ON n.id = wn.node_id
WHERE exist(w.tags, 'addr:housenumber') AND exist(w.tags, 'addr:street')
GROUP BY housenumber, street, postcode, city, country;
CREATE INDEX idx_geocode_full_text ON geocode_optimized USING GIN (full_text);
```
## Run server
Change the database credentials in `src/main/resources/application.properties`.
Run Maven `spring-boot:run`
```bash
mvn spring-boot:run
```
## Geocode
To Geocode an address, just call
```
http://localhost:8080/geocode{?q}
```
To get all addresses, call. **Be careful as this query can retrieve thousands of rows.**
```
http://localhost:8080/geocode`all{?q,sort}
```
You can also sort the result by adding the `sort` parameter:
```
#Sort by city ASC
http://localhost:8080/geocode?q=
&sort=city
#or
http://localhost:8080/geocode?q=&sort=city,ASC
#Sort by city, DESC
http://localhost:8080/geocode?q=
&sort=city,DESC
#Sort by city, DESC and street ASC
http://localhost:8080/geocode?q=
&sort=city,DESC&sort=street,ASC
```
### Pagination and limiting number of results.
To paginate over the results, there are two possibilities:
**Slicing**: Separating the Result with no knowledge about the total number of elements.
Parameters:
- `q`: Address to geocode
- `sort`: Sorting, see example above
- `page`: Page number, starting at `0`, default `0`
- `size`: Number of elements per page, default `10`
```
http://localhost:8080/geocode/sliced{?q,sort,page,size}
```
**Paging**: Separating the Result with knowledge about the total number of elements by making a `COUNT(*)`
statement before executing the query. Depending on the number of total elements and computer resources
this can take longer than the other queries.
Parameters:
- `q`: Address to geocode
- `sort`: Sorting, see example above
- `page`: Page number, starting at `0`, default `0`
- `size`: Number of elements per page, default `10`
```
http://localhost:8080/geocode/paged{?q,sort,page,size}
```
## Reverse geocoding
Slicing and Pagination works exactly the same like with geocoding.
**Reverse Geocode**:
```
#Gives the address with the shortest distance to the given coordinates
http://localhost:8080/reverse{?lat,lng}
#Returns All the addresses for the given coordinates:
http://localhost:8080/reverse/all{?lat,lng,sort} #be careful, no filtering beside lat and lng.
http://localhost:8080/reverse/sliced{?lat,lng,sort,page,size}
http://localhost:8080/reverse/paged{?lat,lng,sort,page,size}
```
**Request**:
```
http://localhost:8080/reverse?lat=47.07119&lon=15.437595916
```
**Result**:
```json
{
"street" : "Hauptplatz",
"housenumber" : "9",
"postcode" : "8010",
"city" : "Graz",
"country" : "AT",
"longitude" : 15.43759591666666,
"latitude" : 47.071199916666664,
"distance" : 1.102684541
}
```