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This article mainly introduces "how java operates gis geometry type data". In daily operation, I believe many people have doubts about how java operates gis geometry type data. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts of "how java manipulates gis geometry type data". Next, please follow the editor to study!

Java manipulates gis geometry type data

Now do the gis business, so need to manipulate the geometry object in postgis, find a lot of libraries, such as geotools, but inexplicably can not download.

There is also jts, but it is not easy to use and it is very complicated to operate. Found another class library-- geolatte-geom and geolatte-geojson.

Used to operate the conversion between geometry and String as well as json. Json and geojson personally understand that the output format is different. Some geometry-specific attributes have been added.

It is mainly used to transfer String to geometry object, wkt and wkb.

The pom.xml file is as follows: org.geolatte geolatte-geom 1.6.0 org.geolatte geolatte-geojson 1.6.0public static void main (String [] args) {/ / the geometry object value directly extracted from the simulation database (he is binary) / / WKT is in the form of a string, similar to the form of "POINT (1 2)" / / so WKT is converted to geometry Equivalent to string to geometry / / WKB to geometry, equivalent to byte to geometry String s = "01020000800200000097E5880801845C404D064F3AF4AE36400000000000000000290A915F01845C40DC90B1A051AE36400000000000000000" Geometry geo = Wkb.fromWkb (ByteBuffer.from (s)); / / geometry object and WKT output are consistent / / Geometry geometry1 = Wkt.fromWkt (wkt); System.out.println ("- Geometry-" + geo.getPositionN (1)); System.out.println ("- wkt-" + Wkt.toWkt (geo)) System.out.println ("- wkb-" + Wkb.toWkb (geo));} java reads database geometry

Recently, because of the need to store some latitude and longitude block information in the database, the Geometry attribute (geometric object) in mysql is used. I have collected a lot of information on the Internet, but there are still all kinds of problems when I really use it, so I recommend a method that may be a bit stupid but practical (my environment springboot tool is sts). Here's an example to illustrate.

Operation

Let's first learn what the spatial data types are in the database.

Introduction to type description example any spatial type of data between Geometry Point coordinate values POINT (104.00924 30.46872) LineString lines, connected by a series of points to form a LINESTRING (11,11,11) Polygon polygon composed of multiple lines POLYGON ((11,22,33,44,55)) MultiPoint point collection class, including multiple points MULTIPOINT (11,22,1) MultiLineString line collection class Contains multiple lines MULTILINESTRING ((11,22), (11,11)) MultiPolygon polygon set classes, contains multiple polygons MULTIPOLYGON (0,10,11,01,0)), ((11,11,11,11,11)) GeometryCollection spatial data collection classes, can include multiple points, lines, polygons GEOMETRYCOLLECTION (POINT (1 1), POINT (3 3), LINESTRING (1 1, 2))

Then insert a test data into the database, inserting a spatial data set containing multiple sets of polygons.

INSERT INTO `geometry` (`geome`) VALUES ('GEOMETRYCOLLECTION (MULTIPOLYGON ((104.009241 30.46892104.009229 30.468961104.009225 30.468997), (104.009241 30.46892104.009229 30.468961225 30.468997)), MULTIPOLYGON ((104.009241 30.468922104.009229 30.468961104.009225 30.468997)

When the data is ready, you are ready to start preparing for the read operation.

Add dependencies in pom.xml to manipulate objects such as Geometry.

Com.vividsolutions jts 1.13

First of all, I wanted to directly determine the type in the entity class and transfer the object directly, but I found that it didn't work after using it, so I directly set it to Object, and the binary system is used to store Geometry in mysql, so the binary is directly converted to Geometry object through jts.

/ / private Geometry geom; is not feasible private Object geomAsBytes; / / the final result is a byte array / / directly convert byte [] in the database to Geometry object public static Geometry getGeometryByBytes (byte [] geometryAsBytes) throws Exception {Geometry dbGeometry = null; / / byte array less than 5, indicating that geometry has a problem if (geometryAsBytes.length

< 5) { return null; } //这里是取字节数组的前4个来解析srid byte[] sridBytes = new byte[4]; System.arraycopy(geometryAsBytes, 0, sridBytes, 0, 4); boolean bigEndian = (geometryAsBytes[4] == 0x00); // 解析srid int srid = 0; if (bigEndian) { for (int i = 0; i < sridBytes.length; i++) { srid = (srid areas= new ArrayList < >

(); try {/ / parses out the spatial collection layer GeometryCollection geometryCollection = (GeometryCollection) GeometryUtil.getGeometryByBytes (data); int geometrySize = geometryCollection.getNumGeometries (); for (int i1 = 0; i1)

< geometrySize; i1++) { try { //解析出多边形集合层 MultiPolygon multiPolygon = (MultiPolygon) geometryCollection.getGeometryN(i1); int size = (int) multiPolygon.getNumPoints(); for (int i = 0; i < size; i++) { try { //解析出多边形 Polygon polygon = (Polygon) multiPolygon.getGeometryN(i); //解析出多边形中的多个点位 Coordinate[] coordinates2 = polygon.getCoordinates(); int size2 = coordinates2.length; Area area = new Area(); area.area_pts = new ArrayList < >

(); for (int j = 0; j < size2; jacks +) {/ / Point object is just one x, one y data Point point = new Point (); point.x = coexistates2 [j] .x Point.y = coexistates2 [j] .y; / / Point set area.area_pts.add (point);} areas.add (area) } catch (Exception e) {break;} catch (Exception e) {break;}} catch (Exception e) {e.printStackTrace ();} return areas At this point, the study on "how java manipulates gis geometry type data" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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