[英]How to convert Geom object from PostGis in R in latitude and longitude?
I have a database that has "location" attribute and it is saved as geom object and looks like this: 0101000020E6100000000000603D1D5EC0000000A06D424740
我有一个具有“位置”属性的数据库,它被保存为 geom 对象,如下所示:
0101000020E6100000000000603D1D5EC0000000A06D424740
Is there a way to extract coordinates from it in R?有没有办法在R中从中提取坐标? These values are loaded in R as strings.
这些值作为字符串加载到 R 中。 Also it gave a warning:
它还给出了警告:
Warning message:
In postgresqlExecStatement(conn, statement, ...) :
RS-DBI driver warning: (unrecognized PostgreSQL field type geometry (id:18832) in column 2)
Any help appreciated.任何帮助表示赞赏。
Have you tried using the rgeos
functions?您是否尝试过使用
rgeos
函数? One option would be reading WKT directly from the database (using ST_AsText
)...一种选择是直接从数据库中读取 WKT(使用
ST_AsText
)...
SELECT ST_AsText('0101000020E6100000000000603D1D5EC0000000A06D424740');
st_astext
------------------------------------------
POINT(-120.456871032715 46.518970489502)
(1 Zeile)
In R, using readWKT
you can then extract the coordinate pair:在 R 中,使用
readWKT
然后可以提取坐标对:
> readWKT("POINT(-120.456871032715 46.518970489502)")
SpatialPoints:
x y
1 -120.4569 46.51897
Coordinate Reference System (CRS) arguments: NA
Another option would be to read x,y directly from the database using ST_X
and ST_Y
:另一种选择是使用
ST_X
和ST_Y
直接从数据库读取x,y :
SELECT ST_X('0101000020E6100000000000603D1D5EC0000000A06D424740'),
ST_Y('0101000020E6100000000000603D1D5EC0000000A06D424740');
st_x | st_y
-------------------+-----------------
-120.456871032715 | 46.518970489502
(1 Zeile)
I see that Jim Jones answer used mainly postgis and not R. The SF package allows for the conversion of Well Known Binary (WKB) to a simple features column (sfc), which in turn can be converted to coordinates.我看到Jim Jones 的回答主要使用 postgis 而不是 R。SF 包允许将众所周知的二进制 (WKB) 转换为简单的特征列 (sfc),然后可以将其转换为坐标。
st_as_sfc documentation st_as_sfc 文档
code:代码:
library(sf)
#> Warning: package 'sf' was built under R version 4.0.3
#> Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1
wkb = structure(list("0101000020E6100000000000603D1D5EC0000000A06D424740"), class = "WKB")
st_as_sfc(wkb,EWKB = TRUE) %>% st_coordinates()
#> X Y
#> 1 -120.4569 46.51897
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