The document describes a command line application called "geom" for performing geometry operations on Well-Known Text (WKT) representations of geometric objects. It lists various commands for buffering, projecting, combining, drawing, and generating random geometries. The commands can be chained together using Unix pipes to perform multi-step operations on geometric objects encoded as text streams.

1. geometry commands
Jared Erickson
CUGOS
June 20th 2012

2. What is it?
Command line application for
geometry

3. Buffer a point
echo "POINT (1 1)" | geom buffer -d 100
Reproject a Point
echo "POINT (1 1)" | geom project -s "EPSG:4326" -t "EPSG:2927"
Generate random points
echo "POINT (1 1)" | geom buffer -d 100 | geom random -n 200

5. "Write programs that do
one thing and do it well.
Write programs to work
together.Write programs
to handle text streams,
because that is a universal
interface."

6. Write programs that do
one thing and do it well...
buffer centroid envelope convexHull voronoiDiagram

7. Write programs to work
together...
Unix Pipes
stdin -> program -> stdout
... program -> stdout -> stdin -> program ...
buffer | centroid | envelope
wkt -> buffer -> wkt | wkt -> centroid -> wkt | wkt -> envelope -> envelope

8. Write programs to handle
text streams...
WKT
POINT (1 1)
LINESTRING (0 0, 5 5, 10 10)
POLYGON ((0 0, 0 10, 10 10, 10 0, 0 0))

9. Geometry Commands
• Java command line application
• JTS - Geometry
• Proj4j - Projections
• Args4j - Command line parsing
• https://github.com/jericks/geometrycommands

10. Commands
geom list
list arc arcpoly area boundary buffer centroid combine
contains convexHull coordinates count countpoints coveredby
covers crosses delaunay densify draw
dump ellipse difference hausdorffdistance disjoint distance
distanceline envelope equals interiorpoint interpolatepoint
intersection intersects isclosed isempty isrectangle isring issimple
isvalid iswithindistance kochsnowflake linemerge locatepoint type grid
endpoint get startpoint mincircle minclearance mindiameter minrect
node normalize octagonalenvelope overlaps placepoint pointatangle
polygonize project random randomwalk rectangle
reflect relate reverse rotate scale shear sierpinskicarpet similarity
simplify sinestar snap squircle subline supercircle symdifference text
touches translate union voronoi within

11. Process
echo "POINT (10 10)" | geom buffer -d 5
POLYGON ((15 10, 14.903926402016152 9.024548389919358, 14.619397662556434 8.08658283817455, 14.157348061512726
7.222148834901989, 13.535533905932738 6.464466094067262, 12.777851165098012 5.842651938487274, 11.91341716182545
5.380602337443566, 10.975451610080642 5.096073597983848, 10 5, 9.024548389919358 5.096073597983848, 8.086582838174552
5.380602337443566, 7.22214883490199 5.842651938487274, 6.464466094067262 6.464466094067262, 5.842651938487274
7.222148834901989, 5.380602337443566 8.086582838174554, 5.096073597983847 9.024548389919362, 5 10.000000000000004,
5.096073597983849 10.975451610080647, 5.380602337443569 11.913417161825455, 5.842651938487277 12.777851165098017,
6.4644660940672685 13.535533905932743, 7.222148834901996 14.157348061512732, 8.08658283817456 14.619397662556437,
9.024548389919369 14.903926402016154, 10.000000000000012 15, 10.975451610080654 14.90392640201615,
11.913417161825462 14.619397662556429, 12.777851165098024 14.157348061512717, 13.535533905932748
13.535533905932725, 14.157348061512735 12.777851165097996, 14.619397662556441 11.913417161825432,
14.903926402016156 10.975451610080622, 15 10))

12. Compare
echo "POINT (10 10)" | geom buffer -d 5 | geom
contains -o "POINT (5 5)"
false

13. Reproject
echo "POINT (1 1)" | geom project -s "EPSG:4326" -t
"EPSG:2927"
POINT (39722967.09614658 19129704.97907105)

14. Draw
echo "POINT (10 10)" | geom buffer -d 5 | geom draw
&& open image.png

15. Call command per line
cat > points.wkt
POINT (1 1)
POINT (2 2)
cat points.wkt | while read line; do geom buffer -d 10 -g
"$line"; done;
POLYGON ((11 1, 10.807852804032304 -0.9509032201612824, … , 10.807852804032311 2.9509032201612437, 11 1))
POLYGON ((12 2, 11.807852804032304 0.0490967798387176, … , 12 2))
cat points.wkt | while read -r line; do geom buffer -d 10 -g
"$line"; done
POLYGON ((11 1, 10.807852804032304 -0.9509032201612824, … , 11 1))
POLYGON ((12 2, 11.807852804032304 0.0490967798387176, … , 12 2))

16. Combine
cat points.wkt | while read -r line; do geom buffer -d 10 -g
"$line"; done | geom combine
MULTIPOLYGON (((11 1, 10.807852804032304 -0.9509032201612824, 10.238795325112868 -2.826834323650898, 9.314696123025453
-4.555702330196022, 8.071067811865476 -6.071067811865475, 6.555702330196023 -7.314696123025453, 4.826834323650898
-8.238795325112868, 2.9509032201612833 -8.807852804032304, 1.0000000000000007 -9, -0.9509032201612819 -8.807852804032304,
-2.826834323650897 -8.238795325112868, -4.55570233019602 -7.314696123025453, -6.071067811865475 -6.0710678118654755,
-7.314696123025453 -4.555702330196022, -8.238795325112868 -2.8268343236508944, -8.807852804032306 -0.9509032201612773, -9
1.0000000000000075, -8.807852804032303 2.950903220161292, -8.238795325112862 4.826834323650909, -7.3146961230254455
6.555702330196034, -6.071067811865463 8.071067811865486, -4.555702330196008 9.314696123025463, -2.826834323650879
10.238795325112875, -0.9509032201612606 10.807852804032308, 1.0000000000000249 11, 2.950903220161309 10.807852804032299,
4.826834323650925 10.238795325112857, 6.555702330196048 9.314696123025435, 8.071067811865499 8.07106781186545,
9.314696123025472 6.555702330195993, 10.238795325112882 4.826834323650862, 10.807852804032311 2.9509032201612437, 11 1)),
((12 2, 11.807852804032304 0.0490967798387176, 11.238795325112868 -1.826834323650898, 10.314696123025453
-3.5557023301960218, 9.071067811865476 -5.071067811865475, 7.555702330196023 -6.314696123025453, 5.826834323650898
-7.238795325112868, 3.9509032201612833 -7.807852804032304, 2.0000000000000004 -8, 0.0490967798387181 -7.807852804032304,
-1.826834323650897 -7.238795325112868, -3.55570233019602 -6.314696123025453, -5.071067811865475 -5.0710678118654755,
-6.314696123025453 -3.5557023301960218, -7.238795325112868 -1.8268343236508944, -7.807852804032306 0.0490967798387227, -8
2.0000000000000075, -7.8078528040323025 3.950903220161292, -7.2387953251128625 5.826834323650909, -6.3146961230254455
7.555702330196034, -5.071067811865463 9.071067811865486, -3.5557023301960076 10.314696123025463, -1.8268343236508788
11.238795325112875, 0.0490967798387394 11.807852804032308, 2.000000000000025 12, 3.950903220161309 11.807852804032299,
5.826834323650925 11.238795325112857, 7.555702330196048 10.314696123025435, 9.071067811865499 9.07106781186545,
10.314696123025472 7.555702330195993, 11.238795325112882 5.826834323650862, 11.807852804032311 3.9509032201612437, 12 2)))

17. Dump
echo "POINT (1 1)" | geom buffer -d 100 | geom random -
n 100 | geom dump > random.wkt
POINT (23.161455744394658 -77.95246871808072)
POINT (58.930083365685135 -61.904759742385096)
POINT (-68.59023262463613 -54.78626222287515)
POINT (-82.5800340659446 -28.375102984177744)
POINT (62.05862576956568 45.25807594023459)
POINT (74.43518384825472 -10.092639433362095)
…

18. Draw multiple geometries
echo "POINT (10 10)" > geoms.wkt
cat geoms.wkt | geom buffer -d 10 >> geoms.wkt
cat geoms.wkt | geom combine | geom draw && open
image.png

19. Draw multiple geometries
echo "POINT (100 100)" > geoms.wkt
cat geoms.wkt | geom get -n 0 | geom buffer -d 10 >> geoms.wkt
cat geoms.wkt | geom get -n 0 | geom buffer -d 20 >> geoms.wkt
cat geoms.wkt | geom get -n 0 | geom buffer -d 30 >> geoms.wkt
cat geoms.wkt | geom combine | geom draw && open image.png

20. Point at Angle
echo "POINT (10 10)" > center.wkt
cat center.wkt | geom pointatangle -a 0 -d 10 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 45 -d 5 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 90 -d 10 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 135 -d 5 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 180 -d 10 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 225 -d 5 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 270 -d 10 >> center.wkt
cat center.wkt | geom get -n 0 | geom pointatangle -a 315 -d 5 >> center.wkt
cat center.wkt | geom combine | geom draw && open image.png

21. Backtics
echo "POINT (10 10)" > point.wkt
echo "POINT (0 0)" | geom buffer -d 10 | geom
contains -o "`cat point.wkt | geom get -n 0`"
false

22. Generate Random Points
echo "POINT (1 1)" | geom buffer -d 100 | geom
random -n 20
MULTIPOINT ((28.654023089302072 -44.01821817278271), (81.83017489687163 -23.86819073039706), (2.105166479839937
36.12893454538721), (4.227942694802536 -75.42526935983172), (70.36226203781283 55.09734125747187), (-24.57828687972821
40.21049354265716), (43.29398472591029 91.04707992971149), (-10.753927532104086 29.320031764200024),
(-81.14902146405959 8.312362640063384), (29.670956290372317 1.1014786268571584), (42.092039630473465
83.01841893953664), (-3.8268655554251154 -33.81236693090035), (-54.61643432275327 -69.03248995687024),
(18.216453654179105 -46.68047579703787), (69.16611402164975 31.101723885056686), (-43.36423562242582
-76.70347656510657), (84.68024160811188 -46.630576818012635), (-52.67048441979452 -65.85207992789142),
(-82.00381658701411 -14.714381798142469), (72.18321150088343 -60.363316389278076))

23. Random Walk
echo "POINT (100 100)" | geom randomwalk -n 100 -a 45
-d 10 | geom draw -c && open image.png

24. Koch Snowflake
echo "POINT (1 1)" | geom envelope -e 100 | geom
kochsnowflake -n 1000 | geom draw && open image.png

25. Sierpinski Carpet
echo "POINT (1 1)" | geom envelope -e 100 | geom
sierpinskicarpet -n 1000 | geom draw && open
image.png

26. Text
geom text -t "Hi" | geom draw -c && open image.png

27. Sine Star
echo "POINT (100 100)" | geom sinestar -l 0.9 -n 12 -p
1000 -w 500 -h 500 | geom draw && open image.png

28. Rectangle
echo "POINT (100 100)" | geom rectangle -p 30 -w 500 -h
500 | geom draw -c && open image.png

29. Ellipse
echo "POINT (100 100)" | geom ellipse -p 30 -w 500 -h
500 | geom draw -c && open image.png

30. Squircle
echo "POINT (100 100)" | geom squircle -p 30 -w 500 -h
500 | geom draw -c && open image.png

31. Supercircle
echo "POINT (100 100)" | geom supercircle -o 3 -p 100 -
w 500 -h 500 | geom draw -c && open image.png

32. Arc
echo "POINT (100 100)" | geom arc -a 45 -e 90 -d -p 20 -
w 500 -h 500 | geom draw -c && open image.png

33. Arc polygon
echo "POINT (100 100)" | geom arcpoly -a 45 -e 90 -d -p
20 -w 500 -h 500 | geom draw -c && open image.png

34. PostgreSQL
psql -U postgres -d postgres -c "select St_asText
(the_geom) from washington_2927 where fid=5" -t |
geom draw && open image.png

35. PostgreSQL
psql -U postgres -d postgres -c "select St_asText
(st_collect(the_geom)) from washington_2927" -t | geom
draw && open image.png

36. PostgreSQL
psql -U postgres -d postgres -c "select St_asText
(the_geom) from washington_2927" -t | geom combine |
geom draw && open image.png

37. GeoScript: convert to kml
echo "POINT (1 1)" | geom buffer -d 10 | geoscript-
groovy -e "println geoscript.geom.Geometry.fromWKT
(System.in.text).kml"
<Polygon><outerBoundaryIs><LinearRing><coordinates>11.0,1.0 10.807852804032304,-0.9509032201612824
10.238795325112868,-2.826834323650898 9.314696123025453,-4.555702330196022 8.071067811865476,-6.071067811865475
6.555702330196023,-7.314696123025453 4.826834323650898,-8.238795325112868 2.9509032201612833,-8.807852804032304
1.0000000000000007,-9.0 -0.9509032201612819,-8.807852804032304 -2.826834323650897,-8.238795325112868
-4.55570233019602,-7.314696123025453 -6.071067811865475,-6.0710678118654755 -7.314696123025453,-4.555702330196022
-8.238795325112868,-2.8268343236508944 -8.807852804032306,-0.9509032201612773 -9.0,1.0000000000000075
-8.807852804032303,2.950903220161292 -8.238795325112862,4.826834323650909 -7.3146961230254455,6.555702330196034
-6.071067811865463,8.071067811865486 -4.555702330196008,9.314696123025463 -2.826834323650879,10.238795325112875
-0.9509032201612606,10.807852804032308 1.0000000000000249,11.0 2.950903220161309,10.807852804032299
4.826834323650925,10.238795325112857 6.555702330196048,9.314696123025435 8.071067811865499,8.07106781186545
9.314696123025472,6.555702330195993 10.238795325112882,4.826834323650862 10.807852804032311,2.9509032201612437
11.0,1.0</coordinates></LinearRing></outerBoundaryIs></Polygon>

38. GeoScript: draw shapefile
geoscript-groovy -e "println new
geoscript.geom.GeometryCollection(new
geoscript.layer.Shapefile('states.shp').features.collect
{it.geom}).wkt" | geom draw && open image.png

39. GeoScript: write shapefile
echo "POINT (1 1)" | geom buffer -d 100 | geom random -
n 100 | geoscript-groovy -e "new
geoscript.workspace.Directory('.').create(new
geoscript.feature.Schema('random',
[['the_geom','Point','EPSG:4326']])).add
(geoscript.geom.Geometry.fromWKT
(System.in.text).geometries.collect{new
geoscript.feature.Feature(['the_geom': it],null)})"

40. Geocoding
curl "http://geocoder.us/service/csv/geocode?zip=95472" |
awk -F ", " '{print "POINT ("$2 " " $1 ")"}' | geom buffer -d
10 | geom draw && open image.png

41. USGS Earthquakes
curl http://earthquake.usgs.gov/earthquakes/catalogs/
eqs1day-M2.5.txt | awk -F ',' '{if (NR!=1) {print "POINT
("$8" "$7")"}}' | geom combine | geom draw && open
image.png

42. WMS
curl -o map.jpg "http://vmap0.tiles.osgeo.org/wms/vmap0?
LAYERS=basic&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetM
ap&STYLES=&FORMAT=image%2Fjpeg&SRS=EPSG
%3A4326&BBOX=-123.07,46.66,-121.14,47.48&WIDTH=500&HEIG
HT=400"
echo "POINT (-122.429452 47.125627)" | geom buffer -d 0.2 | geom
draw -w 500 -h 400 -e "-123.07,46.66,-121.14,47.48" -i map.jpg &&
open image.png

43. Install
• Install Java
• Download
• https://github.com/jericks/geometrycommands/
downloads
• Put on path
• export PATH = /whereever/you/put/it/geom/bin

44. Help
• View commands
• geom list
• Get help on a command
• geom buffer --help
• Man pages
• man geom
• man geom-buffer

45. Web Site (Sphinx)

46. Extend
• Create a Java class that implements Command
Interface
• or extends GeometryCommand
• or extends OtherGeometryCommand
• Add command line options by creating an
Options subclass with Args4J annotations
• Java Service Provider Interface
• META-INF/services/org.geometrycommands/Command
• Add line with the full path (package and class name)

47. Thank you!