百度地图之收索视野内的建筑物-CFANZ编程社区

1. mysql spatial介绍

从MySQL4.0开始加入了Spatial扩展功能，实现了OpenGIS规定的几何数据类型，在SQL中的简单空间运算。但是MySQL对空间查询的支持不够完善，要进行复杂的空间运算，建议使用postgreSQL数据库的postGIS。

下图是MySQL Spatial接口及类的结构(有背景颜色的框代表接口）：

有关mysql的详细介绍，可以参考一下链接中的文章。

l 官方参考文档（中文）：

http://dev.mysql.com/doc/refman/5.1/zh/spatial-extensions-in-mysql.html#mysql-spatial-datatypes

l 官方参考文档（英文）：

http://dev.mysql.com/doc/refman/5.0/en/spatial-extensions.html

l 关于hibernate支持

http://www.hibernatespatial.org/tutorial.html

拓展mysqlspatial函数：

1) 空间中的点是否相等

[delphi] view plain copy

DELIMITER $$
CREATE DEFINER = 'smart'@'localhost'
FUNCTION ArePointsEqual(p1 POINT,
p2POINT
)
RETURNS TINYINT(1)
DETERMINISTIC
NO SQL
BEGIN
RETURN IsZero(x(p1) -x(p2)) AND IsZero(y(p1) - y(p2));
END
$$
DELIMITER ;

2) 查找区域的中心点

[sql] view plain copy

USE smartu;
DELIMITER $$
CREATE DEFINER = 'smart'@'localhost'
FUNCTION
RETURNS
DETERMINISTIC
NO
BEGIN
DECLARE
DECLARE sw, ne POINT; #South-West and
DECLARE lat, lng DOUBLE;
SET
SET
SET
SET
SET
RETURN
END
$$
DELIMITER ;

3) LineN

[sql] view plain copy

USE smartu;
DELIMITER $$
CREATE DEFINER = 'smart'@'localhost'
FUNCTION
INT
)
RETURNS
DETERMINISTIC
NO
BEGIN
THEN
RETURN NULL;
END
RETURNLineString(pointn(ls, n), pointn(ls, n + 1));
END
$$
DELIMITER ;

4) 计算两点间的空间距离

[sql] view plain copy

USE smartu;
DELIMITER $$
CREATE DEFINER = 'smart'@'localhost'
FUNCTION DISTANCE(lat1 DOUBLE,
lon1DOUBLE,
lat2DOUBLE,
lon2DOUBLE
)
RETURNS DOUBLE
DETERMINISTIC
NO
COMMENT 'counts distance (km) between 2 points on Earth surface'
BEGIN
DECLARE
RETURN
cos(lat1 / dtor) *cos(lat2 / dtor) *
cos(lon2 / dtor - lon1 /dtor)));
END
$$
DELIMITER ;

5) 是否为0

[sql] view plain copy

USE smartu;
DELIMITER $$
CREATE DEFINER = 'smart'@'localhost'
FUNCTION IsZero(n DOUBLE)
RETURNS
DETERMINISTIC
NO
BEGIN
DECLARE
RETURN (abs(n) <=epsilon);
END
$$
DELIMITER ;

2. 项目前台、后台的实现

1) 项目后台实现

l 数据库设计

[sql] view plain copy

--创建表
createtable smart_u_convenience_item_spatial(
varchar(36) not null,
not null,
varchar(20),
varchar(20),
varchar(500),
varchar(500),
primary key
key
)ENGINE=MyISAM;
--往表中插入数据
INSERTINTO smart_u_convenience_item_spatial
SELECTt.convenience_item_id
'POINT(',t.item_latitude, ' ', t.item_longitude, ')'))
, t.item_latitude
, t.item_longitude
, t.convenience_item_code
, t.convenience_item_name
from

l 后台代码使用到的查询点的sql

[sql] view plain copy

SELECT
FROM
SELECT
FROM
smart_u_convenience_item t
WHERE
t.convenience_item_idIN
(SELECTs.item_spatial_id
FROM
smart_u_convenience_item_spatial s
WHERE
intersects(location,
'POLYGON((', 3.9921123E7, ' ', 1.16365462E8,
',', 3.9921123E7, ' ', 1.16441881E8,
',', 3.9879484E7, ' ', 1.16441881E8,
',', 3.9879484E7, ' ', 1.16365462E8,
',', 3.9921123E7, ' ', 1.16365462E8,'))'))))) t
ORDER BY
ASC

2) 前台设计

[java] view plain copy

MKMapViewListener mapViewListener = new
@Override
public void
// 此处可以实现地图移动完成事件的状态监听
"mapMoveFinish");
this.getBsnsDisInfo(BsnsDisAllActivity.this.getGeoPointMap());
}
@Override
public void
","+poi.geoPt.getLongitudeE6());
}
@Override
public void
"onGetCurrentMap");
}
@Override
public void
"onMapAnimationFinish");
this.getBsnsDisInfo(BsnsDisAllActivity.this.getGeoPointMap());
}
};
mMapView.regMapViewListener(app.mBMapManager,mapViewListener);
private
Projectionprojection = mMapView.getProjection();
Map<String,Double>polygon = newHashMap<String,Double>();
0, 0);
"top_x",(double) top.getLatitudeE6());
"top_y",(double)top.getLongitudeE6());
0);
"right_x",(double)right.getLatitudeE6());
"right_y",(double)right.getLongitudeE6());
GeoPointdown = projection.fromPixels(mMapView.getWidth(), mMapView.getHeight());
"down_x",(double)down.getLatitudeE6());
"down_y",(double)down.getLongitudeE6());
0, mMapView.getHeight());
"left_x",(double)left.getLatitudeE6());
"left_y",(double)left.getLongitudeE6());
return
}
private
final
new
public void
try{
new
OrderByEntityorder = newOrderByEntity();
"item_longitude");
"asc");
orderByEntity.add(order);
// OrderByEntityorder2 = new OrderByEntity();
// order.setOrderCol("item_latitude");
// order.setOrderType("asc");
// orderByEntity.add(order2);
null, null);
Log.i(TAG,ack.getAckCode().toString());
Log.i(TAG,ack.getAckMsg().toString());
new
if(ack.getAckCode().toString().indexOf("INFO") != -1){
msg.what = RESULT_BSNS_CAT;
else{
msg.what = RESULT_ERROR;
}
msg.obj = ack;
myHandler.sendMessage(msg);
catch(Exception e){
}
};
}.start();
}
new
public void
switch
case
ConvenienceItemAckEntityack = (ConvenienceItemAckEntity)msg.obj;
pinItemMark(ack.getResults());
break;
default:
break;
}
};
};
private
convenieceItemList= newArrayList<ConvenienceItemEntity>();
mGeoList.clear();
latLoc.clear();
for(inti=0;i<itemList.size();i++){
ConvenienceItemEntityitemEntity = itemList.get(i);
int
int
OverlayItemitem = newOverlayItem(newGeoPoint(lat, loc),itemEntity.getConvenienceItemName() ,itemEntity.getConvenienceItemId());
this).inflate(
null);// 获取要转换的View资源
TextViewTestText = (TextView)drawableView.findViewById(R.id.map_drawable_text);
//将每个点的Title在弹窗中以文本形式显示出来
BitmapdrawableBitmap = convertViewToBitmap(drawableView);
Drawabledraw = newBitmapDrawable(drawableBitmap);
item.setMarker(draw);
convenieceItemList.add(itemEntity);
mGeoList.add(item);
PointlocPoint = newPoint();
1;
locPoint.y = lat;
latLoc.add(locPoint);
}
addMarker(mGeoList);
for (int i = 0; i < latLoc.size(); i++){
for (int j = 1; j < latLoc.size() - i; j++) {
1));
Point p2 = latLoc.get(j);
if(p1.y>p2.y){
Point temp = p1;
1, p2);
latLoc.set(j, p1);
}
if(latLoc.get(j-1).x==0){
1;
}
}
}
}