传单上的显示行

Question

我想在leaflet（对于R）地图显示一行。

我行的要点：

myPoints < - structure(list(lat = c(52.40684, 52.40682, 52.40681, 52.40679, 
52.40675, 52.40669, 52.40668, 52.40661, 52.40641, 52.40623, 52.40608, 
52.40592, 52.40469, 52.40464, 52.40456, 52.40416, 52.4039, 52.40376, 
52.40359, 52.40352, 52.4033, 52.40291, 52.40289, 52.4029, 52.40245, 
52.40232, 52.40097, 52.40032, 52.40006, 52.39995, 52.39987, 52.39988, 
52.40011, 52.40015, 52.40025, 52.40032, 52.40046, 52.4005, 52.40057, 
52.40062, 52.40063, 52.40065, 52.40082, 52.40091, 52.40094, 52.40102, 
52.40104, 52.4011, 52.40114, 52.40181, 52.40181, 52.40187, 52.40221, 
52.40224, 52.40228, 52.40217, 52.40219, 52.40218, 52.4022, 52.40223, 
52.4023, 52.40232, 52.40238, 52.40245, 52.40249, 52.40252, 52.40251, 
52.40248, 52.40232, 52.40222, 52.40201, 52.40183, 52.40172, 52.40161, 
52.40149, 52.40141, 52.40141, 52.40145, 52.40151, 52.40175, 52.40195, 
52.4021, 52.40205, 52.40202, 52.40201, 52.40204, 52.40208, 52.40211, 
52.40213, 52.40219, 52.4022, 52.40216, 52.40209, 52.40204, 52.40201, 
52.402, 52.40202, 52.40206, 52.40212, 52.4022, 52.40223, 52.40224, 
52.40228, 52.4023, 52.40233, 52.40238, 52.40242, 52.40244, 52.40239, 
52.40234, 52.40231, 52.40234, 52.40238, 52.4024, 52.40248, 52.4025, 
52.40245, 52.40234, 52.4022, 52.4017, 52.40156, 52.4015, 52.40144, 
52.40113, 52.40092, 52.40042, 52.39998, 52.39951, 52.3992, 52.39916, 
52.39909, 52.39906, 52.39902, 52.39901, 52.39902, 52.39906, 52.39909, 
52.39916, 52.39898, 52.39888, 52.39876, 52.39874, 52.39869, 52.39858, 
52.398, 52.39712, 52.39685, 52.39612, 52.39575, 52.39574, 52.39562, 
52.39559, 52.39558, 52.39549, 52.3953, 52.39512, 52.39505, 52.39478, 
52.39463, 52.39451, 52.39281, 52.39277, 52.39267, 52.39258, 52.39247, 
52.39242), lng = c(12.97444, 12.97219, 12.97209, 12.97203, 12.97197, 
12.97194, 12.97162, 12.97164, 12.97174, 12.97187, 12.97193, 12.97196, 
12.97191, 12.97189, 12.97181, 12.97228, 12.97262, 12.97295, 12.97349, 
12.97393, 12.97629, 12.98028, 12.98055, 12.98065, 12.98071, 12.98074, 
12.98075, 12.98075, 12.98073, 12.98069, 12.98067, 12.98128, 12.98624, 
12.98744, 12.99267, 12.99438, 12.99775, 12.99832, 12.9994, 13.00018, 
13.0007, 13.00165, 13.00588, 13.00791, 13.00886, 13.009, 13.00909, 
13.0101, 13.01094, 13.01086, 13.01101, 13., 13., 13.01316, 
13.01429, 13.01431, 13.01493, 13.01502, 13.01519, 13.01521, 13.01523, 
13.0153, 13.01579, 13.01596, 13.01602, 13.01607, 13.01623, 13.01632, 
13.01657, 13.01709, 13.01778, 13.01812, 13.01823, 13.0183, 13.01836, 
13.01839, 13.01857, 13.01976, 13.02107, 13.02707, 13.03184, 13.0357, 
13.03572, 13.03578, 13.03593, 13.03599, 13.03602, 13.03602, 13.0367, 
13.03808, 13.03829, 13.0383, 13.03835, 13.03844, 13.03856, 13.03868, 
13.0388, 13.0389, 13.03897, 13.03901, 13.03901, 13.03924, 13.04057, 
13.04103, 13.04104, 13.04108, 13.04113, 13.04128, 13.04142, 13.04146, 
13.04147, 13.04194, 13.04295, 13.04346, 13.04519, 13.04547, 13.04555, 
13.0457, 13.04589, 13.04663, 13.04689, 13.04698, 13.04701, 13.04717, 
13.04729, 13.04755, 13.04774, 13.04786, 13.04801, 13.04802, 13.04795, 
13.04788, 13.04766, 13.04759, 13.04766, 13.04788, 13.04795, 13.04802, 
13.04811, 13.04818, 13.04833, 13.04842, 13.04842, 13.04842, 13.04843, 
13.04841, 13.04839, 13.04825, 13.05091, 13.05121, 13.05225, 13.05242, 
13.05254, 13.05251, 13.05242, 13.05229, 13.05259, 13.05487, 13.0561, 
13.05704, 13.05646, 13.05654, 13.05735, 13.05803, 13.05881, 13.05924 
)), .Names = c("lat", "lng"), row.names = c(NA, -166L), class =  "data.frame") 

那我该怎么做SpatialLine出来的

makeLine <- function(myMatrix) { 
    library(sp) 
    if (nrow(myMatrix) > 1) { 
      myLine <- Line(myMatrix) 
      myLinesList <- Lines(list(myLine), 1) 
      myLineSpatial <- SpatialLines(list(myLinesList)) 
      proj4string(myLineSpatial) <- CRS("+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs") 
      return(myLineSpatial) 

    } else { 
      print("Matrix to short") 
    } 
} 

mySpatialLine <- makeLine(myPoints)后，我有这个

class  : SpatialLines 
features : 1 
extent  : 52.39242, 52.40684, 12.97162, 13.05924 (xmin, xmax, ymin, ymax) 
coord. ref. : +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs 

然后我试着带上我的leaflet地图。

leafletProxy("myMap") %>% 
    addPolylines(data = mySpatialLine, stroke = TRUE, 
    fillOpacity = 0.5, smoothFactor = 0.5, layerId = "way" 
) 

这是行不通的。没有显示。我甚至没有收到错误或警告。任何想法为什么？

Answer 1

您分配了错误的坐标参照系。你的点坐标是经度和纬度，但你指定一个单位米的webmercator投影。这基本上意味着即使在最高的缩放级别下，该线太小也无法被看到。

因此：

makeLine <- function(myMatrix) { 
    library(sp) 
    if (nrow(myMatrix) > 1) { 
    myLine <- Line(myMatrix) 
    myLinesList <- Lines(list(myLine), 1) 
    myLineSpatial <- SpatialLines(list(myLinesList)) 
    proj4string(myLineSpatial) <- CRS("+init=epsg:4326") 
    return(myLineSpatial) 

    } else { 
    print("Matrix to short") 
    } 
} 

leaflet() %>% addTiles() %>% 
    addPolylines(data = mySpatialLine, stroke = TRUE, 
       fillOpacity = 0.5, smoothFactor = 0.5, layerId = "way" 
) 

应该工作打算。