Manifoldr allows direct connection to Manifold .map projects from R via ODBC. We can read tables in full, or issue SQL queries to select or dynamically create new tables.
library(manifoldr)
mapfile <- system.file("extdata", "AreaDrawing.map", package = "manifoldr")
(x <- Drawing(mapfile))
#> Simple feature collection with 31 features and 2 fields
#> geometry type: GEOMETRY
#> dimension: XY
#> bbox: xmin: -615.2802 ymin: -565.2889 xmax: 1334.871 ymax: 612.3995
#> epsg (SRID): NA
#> proj4string: NA
#> First 20 features:
#> ID Name geometry
#> 1 10 L POLYGON((-178 168, -169 -27...
#> 2 11 E POLYGON((10 177, 11 167, 27...
#> 3 12 G POLYGON((183.5 98, 199.5 -7...
#> 4 13 I POLYGON((406.5 182, 413.5 -...
#> 5 14 O POLYGON((513.5 142, 526.5 3...
#> 6 15 N POLYGON((732.5 201, 754.5 -...
#> 7 22 LINESTRING(-615.28015075376...
#> 8 24 LINESTRING(1315.8756281407 ...
#> 9 26 O POINT(513.5 142)
#> 10 27 POINT(526.5 38)
#> 11 28 POINT(548.5 -21)
#> 12 29 POINT(634.5 -36)
#> 13 30 POINT(668.5 -17)
#> 14 31 POINT(687.5 38)
#> 15 32 POINT(687.5 122)
#> 16 33 POINT(682.5 161)
#> 17 34 POINT(660.5 189)
#> 18 35 POINT(628.5 200)
#> 19 36 POINT(576.5 199)
#> 20 37 POINT(551.5 183)Note the mixed types which are now available in R via sf
Basic Manifold queries work, using the "WHERE" argument.
Drawing(mapfile, WHERE = "WHERE [Type (I)] = 2")
#> Simple feature collection with 2 features and 2 fields
#> geometry type: LINESTRING
#> dimension: XY
#> bbox: xmin: -615.2802 ymin: -565.2889 xmax: 1334.871 ymax: 612.3995
#> epsg (SRID): NA
#> proj4string: NA
#> ID Name geometry
#> 1 22 NA LINESTRING(-615.28015075376...
#> 2 24 NA LINESTRING(1315.8756281407 ...
Drawing(mapfile, WHERE = "WHERE IsLine(ID) AND [Length (I)] < 2500")
#> Simple feature collection with 1 feature and 2 fields
#> geometry type: LINESTRING
#> dimension: XY
#> bbox: xmin: -111.9133 ymin: -321.5201 xmax: 1334.871 ymax: 612.3995
#> epsg (SRID): NA
#> proj4string: NA
#> ID Name geometry
#> 1 24 NA LINESTRING(1315.8756281407 ...Exciting!
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manifoldrrelies on Manifold® System GIS, it's of no use if you don't have this installed and working. -
manifoldris only available from GitHub: the easiest way to install it is to use thedevtoolspackage.
if (packageVersion("devtools") < 1.6) {
install.packages("devtools")
}
devtools::install_github("mdsumner/manifoldr")(Future versions may become available on CRAN. )
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The ODBC driver for Manifold is read-only, so we cannot modify the contents of an existing file.
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Please take care not to modify a Manifold project while an R session has a open connection to it. If you try to save such a project, you will get an error seen below. If you see this, and you want to save your changes you must choose "Yes", and save the file to a new location. There is no other option that I know of:
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Drawings that use a Local Scale different from 1.0 and/or a Local Offset different from 0.0 will not be read with correct geometry. I'm not sure how to work through this yet.
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There are many issues with the conversion from Manifold to WKT or PROJ.4 strings, there's a lot of work to do here.
All the standard Manifold SQL is available.
NOTE: this will be merged with mdsumnner/dplrodbc in some way. Was originally called RforManifold.
Manifold GIS and R make for a powerful partnership, but the coupling between them has been relatively loose and sketchy.
Two key recent R packages make the coupling more compelling:
The main ways we connect R and Manifold are
- read drawing layers with data from Manifold .map files via SQL queries
- drive the Manifold API directly via .Net.
- (developing) simplify the queries via dplyr
The first provides a pretty tight mapping of high-level data types, i.e. in Manifold we have a drawing and in R we have a Spatial layer and moving from one to the other is easy.
The second provides a lot more power but we need to do more work to transfer data between the systems.
There are lots of other pathways, including GDAL as a third/fourth party and via file transfer.
See the package vignettes for examples.
- Large Geoms and other binary types are stored as the
ODBC_binarytype from theRODBCpackage. Be careful with these columns as they do not have compact printing methods. This is something to added to a future version of this package.
- illustrate this example in both R and Manifold
https://github.com/mdsumner/talks/blob/master/SQL_3/SQL_3.rmd
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dig up the RODBC reader https://github.com/mdsumner/mdsutils/blob/master/R/odbcReadManifold.R
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get rClr working with Manifold: install from here https://github.com/jmp75/rClr
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parallel CGAL triangulation code with Manifold's DecomposeToTrianglesAdv