TT12-MCU/applications/map.c

/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2023-06-24     murmur       the first version
 */
/**
 * 本函数通过geojson文件构建电子围栏，并判别是否在围栏内
 * 解析geojson文件，获取多边形经纬度
 * 判断当前坐标是否在多边形内部
 */
#include <rtthread.h>

#define LOG_TAG "map"
#define LOG_LVL  LOG_LVL_INFO
#include <ulog.h>

#include <dfs_file.h>
#include <cJSON.h>

/** .geojson文件
{
    "type":"FeatureCollection",
    "features":[
        {
            "type":"Feature",
            "properties":{

            },
            "geometry":{
                "coordinates":[
                    [
                        [
                            109.84662252076487,
                            18.40384100935684
                        ],
                        [
                            109.84827972641727,
                            18.391934106424912
                        ],
                        [
                            109.86043256475983,
                            18.391829269588243
                        ],
                        [
                            109.86800046865523,
                            18.396651709843837
                        ],
                        [
                            109.86811094900406,
                            18.41132787117354
                        ],
                        [
                            109.85225701894615,
                            18.41284783067367
                        ],
                        [
                            109.84662252076487,
                            18.40384100935684
                        ]
                    ]
                ],
                "type":"Polygon"
            }
        }
    ]
}
 */

/**
 * 解析电子围栏的各顶点
 * @param fin 电子围栏文件，标准*.geojson文件，可通过http://geojson.io/获取
 * @param *x 用于存储经度的数组
 * @param *y 由于存储纬度的数组
 * @return 顶点个数
 */
int mapParse(const char *fin,float *x, float *y)
{
    cJSON *root = RT_NULL, *object = RT_NULL, *item = RT_NULL;

    int fd_in = -1;
    int rst=-RT_ERROR;
    fd_in = open(fin, O_RDONLY, 0);
    if (fd_in < 0)
    {
        LOG_E("[hex] open the input file : %s error.", fin);
        return rst;
    }
    size_t file_size = lseek(fd_in, 0, SEEK_END);
    lseek(fd_in, 0, SEEK_SET);

    rt_uint8_t *buffer = RT_NULL;
    buffer = (rt_uint8_t *) rt_malloc(512);
    read(fd_in, buffer, file_size);
    close(fd_in);
//    LOG_HEX("json",16,buffer,file_size);

    root = cJSON_Parse((const char *) buffer);
    if (!root)
    {
        LOG_W("No memory for cJSON root!");
        goto _exit;
    }
    //坐标所在层级为 root->features[0]->geometry->coordinates[0]
    object = cJSON_GetObjectItem(root, "features");
    if (cJSON_IsArray(object))
    {
//        LOG_D("size of 'features' is %d",cJSON_GetArraySize(object));
        cJSON *tmp  = cJSON_GetArrayItem(object, 0);
        item = cJSON_GetObjectItem(tmp, "geometry");
        if (item)
        {
            cJSON *sitem = cJSON_GetObjectItem(item, "type");
//            LOG_D("type is %s",sitem->valuestring);
            if (rt_strcmp(sitem->valuestring,"Polygon") != 0)
            {
                LOG_E("type is not match, needed to be 'Polygon'");
                goto _exit;
            }

            sitem = cJSON_GetObjectItem(item, "coordinates");
            if (cJSON_IsArray(sitem))
            {
                cJSON *tmp2 = cJSON_GetArrayItem(sitem, 0);
                if (cJSON_IsArray(tmp2))
                {
                    size_t cnt = cJSON_GetArraySize(tmp2)-1;//最后一个是重复的
                    LOG_D("cnt of 'coordinates' pairs is %d", cnt);
                    if (cnt<3) {//至少是个三角形
                        rst = -RT_ERROR;
                        LOG_W("cnt of 'coordinates' pairs is too few.");
                        goto _exit;
                    }
                    for (size_t var = 0; var < cnt; var++)
                    {
                        cJSON *llp = cJSON_GetArrayItem(tmp2, var);
                        if (cJSON_IsArray(llp))
                        {
                            float lon = cJSON_GetNumberValue(cJSON_GetArrayItem(llp, 0)); //经度
                            x[var]= lon;
                            float lat = cJSON_GetNumberValue(cJSON_GetArrayItem(llp, 1)); //维度
                            y[var]= lat;
                            LOG_D("%lf-%lf", x[var], y[var]);
                            rst = cnt;
                        }
                    }
                }
            }
        }
    }
_exit:
    cJSON_Delete(root);
    rt_free(buffer);
    return rst;
}


//  Globals which should be set before calling this function:
//
//  int    polyCorners  =  how many corners the polygon has
//  float  polyX[]      =  horizontal coordinates of corners
//  float  polyY[]      =  vertical coordinates of corners
//  float  x, y         =  point to be tested
//
//  (Globals are used in this example for purposes of speed.  Change as
//  desired.)
//
//  The function will return YES if the point x,y is inside the polygon, or
//  NO if it is not.  If the point is exactly on the edge of the polygon,
//  then the function may return YES or NO.
//
//  Note that division by zero is avoided because the division is protected
//  by the "if" clause which surrounds it.
/**
 * 判断某点是否在多边形内部，移植至http://alienryderflex.com/polygon/
 * @param polyCorners 多边形顶点个数
 * @param polyX x坐标数组，对应经度
 * @param polyY y坐标数组，对应纬度
 * @param x 点的x坐标
 * @param y 点的y坐标
 * @return
 */
int pointInPolygon(int polyCorners,float polyX[], float polyY[],float x,float y)
{

  int   i, j=polyCorners-1 ;
  int  oddNodes=0      ;

  for (i=0; i<polyCorners; i++) {
    if ((polyY[i]< y && polyY[j]>=y
    ||   polyY[j]< y && polyY[i]>=y)
    &&  (polyX[i]<=x || polyX[j]<=x)) {
      oddNodes^=(polyX[i]+(y-polyY[i])/(polyY[j]-polyY[i])*(polyX[j]-polyX[i])<x); }
    j=i; }

  return oddNodes;
}

static demo(int argc, char **argv)
{
    char *f = "/map.geojson";
    if (argc == 2)
    {
        rt_strcpy(f,argv[1]);
    }

    float polyX[10]={},polyY[10]={};
//    cmd_free();
    int polyCorners =  mapParse(f,polyX,polyY);
    for (uint8_t var = 0; var < polyCorners; var++) {
        LOG_I("%d=%d.%d,%d.%d",var+1,
                (int)polyX[var],(int)((long)(polyX[var]*1000000) % 1000000),
                (int)polyY[var],(int)((long)(polyY[var]*1000000) % 1000000));
    }
//    cmd_free();
}
MSH_CMD_EXPORT_ALIAS(demo,d_parseFence,解析围栏);