https://github.com/filonenko-mikhail/cl-ewkb.git

```
git clone 'https://github.com/filonenko-mikhail/cl-ewkb.git'
```

(ql:quickload :cl-ewkb)

★5

cl-ewkb is a geospatial library, based on cl-wkb, that implements the OGC Well-Known Binary geographic geometry data model with PostGIS 3d, 4d extensions, and provides WKB and EWKB encoding and decoding functionality. cl-wkb author is J.P. Larocue. Library also provide module cl-wkb, which has CLOS-based API like http://enroutesystems.com/software/cl-wkb/ with PostGIS extensions.

Depends on: ieee-floats flexi-streams

PostGIS extension WKB is described in postgis-1.5/doc/ZMSgeoms.txt All extensions are supported: 3dz, 3dm, 4d, embedded SRID.

Exported structs

point-primitive x y pointz-primitive x y z pointm-primitive x y m pointzm-primitive x y z m point-primtive structs contain coordinates (2d, 3d, 4d)

linear-ring points-primitive linear-ring struct contains array of point-primitive

geometry type srid geometry parent struct for other types and also contains “GEOMETRYCOLLECTION”

point type srid point-primitive line-string type srid points-primitive polygon type srid linear-rings multi-point type srid points multi-line-string type srid line-strings multi-polygon type srid polygons geometry-collection type srid geometries

Exported functions

(decode octets) Decode from wkb sequence (decode-from stream) Decode from wkb stream

Functions for encoding:

(encode object endianness) Encode object to vector

(encode-to object stream endianness) Encode object to stream with endianness

Example:

Getting data from postgresql and decode it:

(decode (caar (postmodern:query (:select (:ST_AsEWKB “SRID=4326;LINESTRING(0 0 1 2, 1 1 2 3, 2 2 3 4)”)))))

Result:

#(CL-EWKB::LINEAR-RING #(#(CL-EWKB::POINT-PRIMITIVE 0.0d0 0.0d0 CL-EWKB::POINTZ-PRIMITIVE 1.0d0 CL-EWKB::POINTZM-PRIMITIVE 2.0d0) #(CL-EWKB::POINT-PRIMITIVE 1.0d0 1.0d0 CL-EWKB::POINTZ-PRIMITIVE 2.0d0 CL-EWKB::POINTZM-PRIMITIVE 3.0d0) #(CL-EWKB::POINT-PRIMITIVE 2.0d0 2.0d0 CL-EWKB::POINTZ-PRIMITIVE 3.0d0 CL-EWKB::POINTZM-PRIMITIVE 4.0d0))) CL-EWKB::LINESTRING)

Drawing data with opengl (using cl-opengl):

Draw pointXX-primitive

(defun draw-point-primitive (point) (cond ((point-primitive-p point) (gl:vertex (point-primitive-x point) (point-primitive-y point))) ((pointz-primitive-p point) (gl:vertex (point-primitive-x point) (point-primitive-y point) (pointz-primitive-z point))) ((pointm-primitive-p point) (gl:vertex (point-primitive-x point) (point-primitive-y point) 0.0 (pointm-primitive-m point))) ((pointzm-primitive-p point) (gl:vertex (point-primitive-x point) (point-primitive-y point) (pointz-primitive-z point) (pointzm-primitive-m point)))))

Drawing objects

(defun draw-point (point) (gl:with-primitives :points (draw-point-primitive (point-primitive point))))

(defun draw-points (line-string) (gl:with-primitives :line-strip (map 'nil (lambda (point) (draw-point-primitive point)) (line-string-points-primitive line-string))))

General drawing function

(defun draw-gisobject (object) (cond ((point-p object) (draw-point object)) ((line-string-p object) (draw-points object))))