Creating stunning maps with GeoServer With SLD, CSS, YSLD and MBStyles

Transcript

1. Creating stunning maps
   with GeoServer
   With SLD, CSS, YSLD and MBStyles
   Ing. Andrea Aime
   GeoSolutions
   1
   

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2. GeoSolutions
   ⚫
   Founded in Italy in late 2006
   ⚫
   Expertise
   • Image Processing, GeoSpatial Data Fusion
   • Java, Java Enterprise, C++, Python
   • JPEG2000, JPIP, Advanced 2D visualization
   ⚫
   Supporting/Developing FOSS4G projects
   ⚫
   GeoServer, MapStore
   ⚫
   GeoNetwork, GeoNode, Ckan
   ⚫
   Clients
   ⚫
   Public Agencies
   ⚫
   Private Companies
   ⚫
   http://www.geo-solutions.it
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3. Quick tour of styling languages
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4. Languages
   SLD 1.0
   core
   SLD 1.1
   core
   YSLD
   extension
   MBStyles
   community
   GeoCSS
   extension
   SLD 1.0
   inspired
   object
   model, with
   extensions
   parse
   parse
   parse
   parse
   and translate
   parse
   and translate
   4
   Map
   rendering
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5. Shared concepts
   ⚫
   Layer (the styles applies to)
   ⚫
   Rules
   ⚫
   Filters/selectors (what should be painted)
   ⚫
   Scale dependencies (zoomed in, zoomed out?)
   ⚫
   Symbolizers (how should it be painted)
   ⚫
   Point
   ⚫
   Line
   ⚫
   Polygon
   ⚫
   Text
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6. Styled Layer Descriptor 1.0 and 11
   ⚫
   The only OGC styling standard
   ⚫
   XML based, verbose, hard to hand edit
   ⚫
   Was meant for machine export but ended
   up being edited a lot by hand
   ⚫
   Autocomplete in the style editor
   ⚫
   Can be generated by external tools and
   imported
   ⚫
   However interoperability is limited
   ⚫
   Often needs to be hand tweaked
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7. SLD 1.0 example
   
   …
   
   
   
   type
   alpine_hut
   
   
   100000.0
   
   
   
   xlink:type="simple"
   xlink:href="symbols/alpinehut.p.16.png"/>
   image/png
   
   
   
   
   
   Filter
   Scale dep.
   Symbolizer
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8. YSLD
   ⚫
   SLD in YAML syntax
   ⚫
   Filtering by CQL
   ⚫
   Can define reusable variables and blocks
   ⚫
   Verbosity it’s between SLD and CSS
   ⚫
   Has a notion of zoom levels, if needed
   feature-styles:
   - rules:
   - filter: type = 'alpine_hut'
   scale: (,100000.0)
   symbolizers:
   - point:
   symbols:
   - external:
   url: symbols/alpinehut.p.16.png
   format: image/png
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9. GeoCSS
   ⚫
   Compact syntax, familiar for web developers
   ⚫
   CQL based filtering, rule nesting and cascading
   keeps complex styling compact (you just
   express the overrides to the base)
   ⚫
   Autocomplete in the style editor
   ⚫
   Does not get any more compact than this:
   ⚫
   Cons: some are confused by “rule cascading”
   → can now be turned off
   [type = 'alpine_hut'][@sd < 100k] {
   mark: url('symbols/alpinehut.p.16.png');
   }
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10. MBStyles (aka MapBox GL)
    ⚫
    JSON based, designed for GUI editing (like
    SLD) instead of hand editing
    ⚫
    Only Web Mercator zoom level based scale
    control
    ⚫
    Symbols coming from “sprites” (symbol
    collections)
    ⚫
    Unlike others, no styling extensions
    ⚫
    No rendering transformations
    ⚫
    Limited expressions usage
    ⚫
    Pro: can be applied both on the client side and
    the server side
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11. MBStyles (aka MapBox GL)
    {
    "version": 8,
    … boilerplate omitted here
    "name": "mountain huts",
    "sprite": "https://my.sever/sprite",
    "layers": [
    {
    "id": "huts",
    "type": "symbol",
    "minzoom": 9,
    "filter": [
    "==",
    "type",
    "alpine_hut"
    ],
    "layout": {
    "icon-image": "alpinehut",
    "icon-size": 1,
    "icon-allow-overlap": true
    }
    }
    ]
    }
    Filter (in postfix notation!)
    Scale dep.
    Symbolizer
    The sprint contains various images,
    like in videogames
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12. What’s next
    ⚫
    Going to explore styling concepts
    ⚫
    Languages used in examples
    ⚫
    SLD 1.0 + GS extensions
    ⚫
    YSLD
    ⚫
    GeoCSS
    YSLD
    SLD
    CSS
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13. Scale dependencies
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14. Types of Scale dependency
    ⚫
    Decide whether to symbolize based on the scale or not
    ⚫
    E.g., at lower scales/lower zoom levels do not show buildings
    ⚫
    Symbolize in a different way depending on the scale
    ⚫
    E.g., different thickness based on the current zoom
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15. Expressing scale dependency filters
    ⚫
    SLD:
    ⚫
    
    1000
    
    ⚫
    
    1000000
    
    ⚫
    CSS
    ⚫
    [@sd > 1k][@sd < 1M]
    ⚫
    Compact expression of large numbers makes them
    readable at a glance, e.g., 100k, 1M
    ⚫
    YSLD:
    ⚫
    scale: (1000, 1000000)
    ⚫
    scale: (1e3, 1e6)
    ⚫
    zoom: (8, 16)
    grid:
    name: WGS84
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16. Unit of Measure
    ⚫
    Useful if you have real world measures of line
    thicknesses and the like
    …
    
    
    #0000FF
    5
    
    
    ...
    …
    stroke: blue;
    stroke-width: 5m;
    …
    line:
    stroke-color: '#0000FF'
    uom: metre;
    stroke-width: '5';
    SLD
    YSLD
    CSS
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17. Transformation functions
    ⚫
    Another way of setting a different value
    depending on the current scale/zoom level
    ⚫
    Useful if the scaling is not linear
    [class = 'highway’
    and type in ('motorway’,
    'motorway_link’)]
    [@sd < 25M] {
    stroke: #e66e89;
    stroke-width: categorize(@sd,
    2, 400k,
    1.9, 800k,
    1.4, 1.5M,
    1, 3M,
    0.8, 6M,
    0.5);
    ⚫
    Less than 400k → 2px
    ⚫
    [400k, 800k] → 1.9px
    ⚫
    [800k, 1.5M] → 1.4px
    ⚫
    [1.5M, 3M] → 1
    ⚫
    [3M, 6M] → 0.8
    ⚫
    Above 6M -> 0.5
    CSS
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18. Transformation functions in SLD
    
    
    #e66e89
    
    
    
    wms_scale_denominator
    
    2
    400000
    1.9
    800000
    1.4
    1500000
    1
    3000000
    0.8
    6000000
    0.5
    
    
    
    
    SLD
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19. Point styling
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20. Simple image
    [type = 'alpine_hut'][@sd < 100k] {
    mark: url('symbols/alpinehut.p.16.png');
    }
    
    
    
    type
    alpine_hut
    
    
    100000.0
    
    
    
    xlink:type="simple"
    xlink:href="symbols/alpinehut.p.16.png"/>
    image/png
    
    
    
    
    SLD
    CSS
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21. Marks (SVG in this case)
    [type = 'bank'][@sd < 6k] {
    mark: symbol('file://symbols/bank.svg');
    :mark { fill: #734a08 };
    mark-size: 14;
    }
    feature-styles:
    - rules:
    - filter: type = 'bank'
    scale: (,6000.0)
    symbolizers:
    - point:
    symbols:
    - mark:
    shape: file://symbols/bank.svg
    fill-color: ! '#734a08'
    size: 14 YSLD
    CSS
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22. Marks composition and override
    [type = 'fountain’] {
    [@sd < 6k] {
    mark: symbol(circle), symbol(circle);
    :nth-mark(1) { fill: #b5d0d0 };
    :nth-mark(2) { fill: #576ddf };
    mark-size: 10, 3;
    };
    [@sd < 3k] {
    mark: symbol('file://symbols/fountain.svg');
    :mark { fill: #576ddf; };
    }
    }
    CSS
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23. ⚫
    Many other options!
    ⚫
    Built-in symbol names (well known marks): circle,
    square, triangle, …
    ⚫
    From TTF fonts using the name
    ttf://#charcode
    ⚫
    Windbarbs, e.g.:
    windbarbs://default(15)[kts]
    ⚫
    WKT specification, e.g.
    wkt://MULTIPOLYGON(((-0.25 -0.25, -0.125 -0.25), (0.125 -0.25,
    0.25 -0.25)), (-0.25 0.25, -0.125 0.25), (0.125 0.25, 0.25
    0.25) …… )
    ⚫
    See more here:
    http://docs.geoserver.org/latest/en/user/styling/sld/exte
    nsions/pointsymbols.html
    Other mark options
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24. Filling polygons
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25. Solid filling
    * {
    fill: lightgrey;
    stroke-width: 0.5;
    }
    
    
    #d3d3d3
    
    
    0.5
    
    SLD
    CSS
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26. Solid fills and repeating images
    fill
    [@sd < 800k][type in ('cemetery', 'grave_yard')] {
    fill: #aacbaf;
    [@sd < 50k] {
    [religion = 'jewish'] {
    fill: #aacbaf, url('symbols/grave_yard_jewish.png');
    };
    [religion = 'christian'] {
    fill: #aacbaf, url('symbols/grave_yard_christian.png');
    };
    [religion = 'INT-generic'] {
    fill: #aacbaf, url('symbols/grave_yard_generic.png');
    };
    };
    } CSS
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27. Filling with repeating images (YSLD)
    feature-styles:
    - rules:
    - filter: type IN ('cemetery','grave_yard')
    scale: (,800000.0)
    symbolizers:
    - polygon:
    fill-color: ! '#aacbaf'
    - filter: (type IN ('cemetery','grave_yard')) AND religion =
    'jewish'
    scale: (,50000.0)
    symbolizers:
    - polygon:
    fill-graphic:
    symbols:
    - external:
    url: symbols/grave_yard_jewish.png
    format: image/png
    # continues in the next slide
    First uniform background fill
    Then foreground symbols for
    various religions
    YSLD
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28. Filling with repeating images (YSLD)
    - filter: (type IN ('cemetery','grave_yard')) AND religion =
    'christian'
    scale: (,50000.0)
    symbolizers:
    - polygon:
    fill-graphic:
    symbols:
    - external:
    url: symbols/grave_yard_christian.png
    format: image/png
    - filter: (type IN ('cemetery','grave_yard')) AND religion =
    'INT-generic'
    scale: (,50000.0)
    symbolizers:
    - polygon:
    fill-graphic:
    symbols:
    - external:
    url: symbols/grave_yard_generic.png
    format: image/png YSLD
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29. Hatching
    
    
    
    
    
    shape://times
    
    #ADD8E6
    
    
    8
    
    
    
    
    
    [@scale < 10000] {
    fill: symbol('shape://times');
    fill-size: 8;
    :fill {
    stroke: #ADD8E6;
    }
    }
    SLD
    CSS
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30. Painting lines
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31. Solid lines (OSM admin borders)
    [type = 'administrative'] {
    [admin_level <= 4],
    [admin_level = 5 or admin_level = 6][@sd <= 400k],
    [admin_level = 7 or admin_level = 8][@sd <= 200k],
    [admin_level = 9 or admin_level = 10][@sd <= 100k] {
    stroke: #ac46ac;
    stroke-opacity: 0.4;
    }
    }
    CSS
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32. Dashes/Marks/images along a line
    * {
    stroke: darkRed, symbol('circle');
    stroke-dasharray: 10 14, 6 18;
    stroke-dashoffset: 14, 0;
    :stroke {
    fill: darkRed;
    size: 6;
    }
    }
    ⚫
    Two coordinated dashed lines
    ⚫
    One made with lines
    ⚫
    One made with circles
    ⚫
    The offset shifts them to have
    one appear in the empty
    spaces of the other
    CSS
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33. Labeling
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34. Vendor options
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35. Point labels and obstacles
    [@sd < 200k] {
    label: [FULLNAME];
    label-anchor: 0.5 1.0;
    label-offset: 0.0 -14.0;
    font-fill: #000033;
    font-family: Arial;
    font-size: 12;
    halo-color: white;
    halo-radius: 1.5;
    label-priority: 200000;
    label-auto-wrap: 100;
    mark: url('./img/landmarks/${IMAGE}’);
    mark-label-obstacle: true;
    }
    «FULLNAME»
    attribute
    Auto wrapping
    label with halo.
    Data driven
    symbol URL
    Labels won’t overlap
    the symbol
    CSS
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36. Line labels
    [@sd < 200k] {
    label: [LABEL_NAME];
    font-fill: #000000;
    font-family: Arial;
    font-size: 13;
    font-style: normal;
    font-weight: bold;
    halo-color: #FFFFFF;
    halo-radius: 1;
    label-follow-line: true;
    label-repeat: 400;
    label-group: true;
    label-max-displacement: 200;
    }
    Draw «LABEL_NAME»,
    black, with white halo
    Draw them along lines,
    fuse segments with
    same label, repeat
    CSS
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37. Polygon labels
    
    
    FULLNAME
    
    
    Arial
    14.0
    bold
    
    
    
    
    0.5
    0.5
    
    
    
    
    #000000
    
    50000
    100
    200
    0.9
    
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38. Raster styling
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39. A DEM and a color map
    ⚫
    SRTM from USGS
    ⚫
    Standard color map
    ⚫
    Also shaded relief (not
    shown in the css below)
    [@sd > 75000] {
    raster-channels: auto;
    raster-color-map:
    color-map-entry(#00BFBF, -100.0, 0)
    color-map-entry(#00FF00, 920.0, 0)
    color-map-entry(#00FF00, 920.0, 1.0)
    color-map-entry(#FFFF00, 1940.0, 1.0)
    color-map-entry(#FFFF00, 1940.0, 1.0)
    color-map-entry(#FF7F00, 2960.0, 1.0)
    color-map-entry(#FF7F00, 2960.0, 1.0)
    color-map-entry(#BF7F3F, 3980.0, 1.0)
    color-map-entry(#BF7F3F, 3980.0, 1.0)
    color-map-entry(#141514, 5000.0, 1.0);
    }
    CSS
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40. Contrast enhancement
    http://docs.geoserver.org/latest/en/user/styling/sld-
    reference/rastersymbolizer.html#contrastenhancement
    
    
    
    
    StretchToMinimumMaximum
    
    50
    800
    
    
    
    GeoServer
    vendor extension
    SLD
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41. Other assorted features
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42. Color blending and alpha compositing
    http://docs.geoserver.org/stable/user/styling/sld-extensions/composite-blend/index.html
    More info
    at:
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43. Z ordering
    http://docs.geoserver.org/latest/en/user/styling/sld-
    extensions/z-order/example.html
    [class = 'motorways'] {
    stroke: #990000, #ff6666;
    stroke-width: 8, 6;
    stroke-linecap: round;
    z-index: 0, 3;
    }
    [class = 'railways'] {
    stroke: #333333;
    stroke-width: 3;
    z-index: 2;
    }
    [class = 'railways'] {
    stroke: #ffffff;
    stroke-width: 1.5;
    stroke-dasharray: 5 5;
    z-index: 3;
    }
    * {
    sort-by: "z_order";
    sort-by-group:
    "roadsGroup";
    } CSS
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44. Geometry transformations
    [@scale < 10000] {
    fill-geometry: [offset(the_geom, 6, -6)];
    fill: darkgray;
    z-index: 0;
    }
    [@scale < 10000] {
    fill: #b3b3b3;
    z-index: 1;
    } CSS
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45. Rendering transformations
    * {
    transform: ras:Contour(levels:
    1100 1200 1300 1400
    1500 1600 1700 1800);
    stroke: black;
    label: [GRAY-INDEX];
    font-fill: black;
    font-family: Sans;
    font-size: 12;
    halo-radius: 2;
    halo-color: white;
    label-follow-line: true
    } CSS
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46. New transform in 2.14: map algebra
    * {
    transform: ras:Jiffle(script:
    ‘ nir = src[7];
    vir = src[3];
    dest = (nir-vir)/(nir+vir);’);
    raster-channels: auto;
    raster-color-map:
    color-map-entry(#00BFBF, -100.0, 0)
    color-map-entry(#00FF00, 920.0, 0)
    …
    } CSS
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47. Desktop tool export
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48. QGIS SLD export work
    ⚫
    In QGIS 2.18, Bonn code sprint improvements
    ⚫
    In QGIS 3.0 support for label exports (thanks for
    OpenGeoGroep sponsoring)
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49. Raster symbolizer export
    ⚫
    Thanks to OSGeo UK
    sponsorship, GeoServer PSC
    donation, and GeoSolutions in-
    kind support
    ⚫
    Available since QGIS 3.4.5
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50. GeoStyler
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51. MapStore styler (in the making)
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52. MapStore styler
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53. SLDEditor
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54. That’s all folks!
    Questions?
    info@geo-solutions.it
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