walkermatt

;; fizzbuzz without conditionals in Clojure

; Simple patten matching using a single map lookup
(defn fizzbuzz [x]
  (let [v [(= (mod x 3) 0) (= (mod x 5) 0)]]
    ({[true false] "fizz"
      [false true] "buzz"
      [true true] "fizzbuzz"
      [false false] x} v)))

walkermatt

Python psycopg2 & PostGIS

Load some data into the database

From the OSGeo4W Shell

ogr2ogr -f PostgreSQL PG:"dbname=postgis host=localhost user=postgres password=postgres" -a_srs "EPSG:27700" county_region.shp -nlt MULTIPOLYGON

Use psycopg2 in the Python Interpreter

walkermatt

# Just the selected features
layer = iface.activeLayer()
for feature in layer.selectedFeatures():
    print feature['name']

# Filter by current extent of the map 
extent = iface.mapCanvas().extent()
request = QgsFeatureRequest()
request.setFilterRect(extent)
layer = iface.activeLayer()

walkermatt

import itertools
import qgis
from qgis.gui import QgsMessageBar
from qgis.core import QgsMapLayer


def layer_info(layer):
    print "Layer name: %s" % layer.name()
    print "CRS: %s" % layer.crs().authid()
    print "Extent: %s" % layer.extent().asWktCoordinates()

walkermatt

// Bounding box of our TMS that define our area of interest
var bbox = [-600000, -300000, 1300000, 1600000];

// Resolutions of our TMS that the tiles will be displayed at calculated so
// that at resolution 0 the bounds fit one 256x256 tile: (maxx - minx)/256
var res = [7421.875, 3710.9375, 1855.46875, 927.734375];

// Define the Proj4Leaflet coordinate reference system base on British National Grid
var crs = L.CRS.proj4js(
    'EPSG:27700',

walkermatt

import json
import lxml
from lxml import objectify

class ObjectifyJSONEncoder(json.JSONEncoder):
    """ JSON encoder that can handle simple lxml objectify types,
        based on the original: https://gist.github.com/aisipos/345559, extended
        to accommodate encoding child nodes with the same tag name as a list.

        Usage:

walkermatt

# Rock, paper, scissors

def beats(thing1, thing2):
  """ Determine who wins rock, paper, scissors
  by passing each players choice """
  if thing1 == thing2:
    # Draw, both players chose the same thing
    return None
  # Determine which thing beats thing2
  victors = {

walkermatt

MapInfo requires a mapinfo.mapinfo_mapcatalog relation to be present in a PostGIS database in order to load relations. The spatialtype column is a float which indicates the geometry type of the relation:

19.0 = POINT, MULTIPOINT
19.1 = LINESTRING, MULTILINESTRING
19.2 = POLYGON, MULTIPOLYGON
19.3 = GEOMETRY

walkermatt

<?xml version="1.0"?>
<FeatureCollection osgb="http://www.ordnancesurvey.co.uk/xml/namespaces/osgb" gml="http://www.opengis.net/gml" fid="GDS-1389940-6811" xsi="http://www.w3.org/2001/XMLSchema-instance" xlink="http://www.w3.org/1999/xlink" schemaLocation="http://www.ordnancesurvey.co.uk/xml/namespaces/osgb http://www.ordnancesurvey.co.uk/xml/schema/v7/OSDNFFeatures.xsd">
    <description>Ordnance Survey, (c) Crown Copyright. All rights reserved, 2013-10-28</description>
    <roadMember>
        <Road fid="osgbfoo">
            <version>5</version>
            <versionDate>2006-02-06</versionDate>
            <theme>Road Network</theme>
            <changeHistory>
                <changeDate>2003-03-13</changeDate>

walkermatt

from json import loads
from collections import namedtuple

url = "http://isharemaps.surreyheath.gov.uk/getdata.aspx"
params = {
    'type': 'json',
    'RequestType': 'LocationSearch',
    'gettotals': 'true',
    'axuid': '1344265603167',
    'mapsource': 'SurreyHeath/AllMaps',