Maplat - Map technology explanation, for implementation based on Map API other than OpenLayers/maplat-coordinates

How to transform coordinate systems in Maplat

Transcript

1. - Map technology explanation,
   for implementation based on Map API
   other than OpenLayers
   Kohei Otsuka – Code for History
   1
   

   View Slide

2. English explanation
   2
   

   View Slide

3. List of terms for understanding
   Maplat principles (coordinates)
   Terms Meaning Accurate map Inaccurate map
   merc EPSG:3857 (Web
   Mercator)
   EPSG:3857 EPSG:3857
   xy XY in each coordinate
   system
   EPSG:3857 XY starting point at the
   top left of the image
   (pixel coordinates when
   not scaled)
   sysCoord Convenience
   coordinates for
   processing with the
   map API (coordinates
   used to set up marker
   pins in the original map
   API)
   For OpenLayers,
   EPSG:3857
   For OpenLayers,
   EPSG:3857 for
   convenience (not
   related to actual
   geographic
   coordinates)
   3
   Quote from https://github.com/code4history/MaplatCore/issues/19
   

   View Slide

4. List of terms for understanding
   Maplat principles (area)
   Terms Meaning Note
   size Display range in pixel width, height
   radius Display range radius in sysCoord
   definition
   Calculated based on a circle half
   the size of the size, not the
   full ”size” range
   viewPoint Center point + zoom + rotate in sysCoord
   definition
   sysCoord
   s
   5 points in sysCoord definition (center,
   top, bottom, left, right)
   xys 5 points in xy definition
   mercs 5 points in merc definition
   4
   Quote from https://github.com/code4history/MaplatCore/issues/19
   

   View Slide

5. Maplat map switching principle 5
   Map coordinates A
   Map coordinates B
   Get center,
   zoom,
   rotate
   viewPoint2SysCoords
   SysCoords xys
   mercs
   Set center,
   zoom,
   rotate
   SysCoords xys
   sysCoords2Xys xys2Mercs
   sysCoords2ViewPoint xys2SysCoords mercs2Xys
   

   View Slide

6. How to use several Maplat libraries (1) 6
   Get center,
   zoom,
   rotate
   SysCoords xys
   mercs
   Set center,
   zoom,
   rotate
   SysCoords xys
   sysCoords2Xys xys2Mercs
   xys2SysCoords mercs2Xys
   MaplatCore
   Internally used
   MaplatTin 5 times
   Internally used
   MaplatTin 5 times
   Map coordinates A
   Map coordinates B
   viewPoint2SysCoords
   sysCoords2ViewPoint
   

   View Slide

7. Maplat
   MaplatCore
   7
   Foreground map
   OpenLayers
   Background map
   OpenLayers
   Map display control
   Coordinates transformation
   UI
   How to use several Maplat libraries (2)
   

   View Slide

8. Maplat
   MaplatCore
   MaplatSwitch
   8
   UI
   Make this process independent
   as MaplatSwitch in the future
   How to use several Maplat libraries (3)
   Foreground map
   OpenLayers
   Background map
   OpenLayers
   Map display control
   Coordinates transformation
   

   View Slide

9. How to realize Maplat 9
   Overlay Switch
   ※ If you want to use OpenLayers as a map API, it is already implemented in Maplat/MaplatCore, and
   you can optionally switch between Overlay/Switch, so assume that you want to use other map APIs.
   Foreground map
   Map API
   Background map
   Map API
   Map API
   MaplatCore or
   MaplatSwitch
   Realtime control
   MaplatCore or
   MaplatSwitch
   Coordinates transformation
   Switch displaying map
   

   View Slide

10. 日本語説明
    10
    

    View Slide

11. Maplat原理理解の用語一覧
    (座標)
    呼称 意味 正確な地図 不正確な地図
    merc EPSG:3857 (Webメルカ
    トル)
    EPSG:3857 EPSG:3857
    xy 各座標系でのXY EPSG:3857 画像左上起点XY (非縮小時
    のピクセル座標)
    sysCoord 地図APIで処理するための
    便宜的座標 (オリジナルの
    地図APIでマーカーピンを
    立てたりする際に使う座
    標)
    OpenLayersの場合は
    EPSG:3857
    OpenLayersの場合は、
    便宜的なEPSG:3857 (実際
    の地理座標とは無関係)
    11
    Quote from https://github.com/code4history/MaplatCore/issues/19
    

    View Slide

12. Maplat原理理解の用語一覧
    (領域)
    呼称 意味 備考
    size pixelでの表示範囲 width, height
    radius sysCoord定義での表示範囲半径 sizeの範囲いっぱいいっぱいではな
    く、半分の大きさの円を元に算出
    viewPoint sysCoord定義での中心点+zoom+rotate
    sysCoord
    s
    sysCoord定義での中心点+上下左右4点の5
    点
    xys xy定義での中心点+上下左右4点の5点
    mercs merc定義での中心点+上下左右4点の5点
    12
    Quote from https://github.com/code4history/MaplatCore/issues/19
    

    View Slide

13. Maplat地図切り替えの原理 13
    地図座標系A
    地図座標系B
    center,
    zoom,
    rotate
    取得
    viewPoint2SysCoords
    SysCoords xys
    mercs
    center,
    zoom,
    rotate
    設定
    SysCoords xys
    sysCoords2Xys xys2Mercs
    sysCoords2ViewPoint xys2SysCoords mercs2Xys
    

    View Slide

14. Maplatライブラリ使い分け (1) 14
    地図座標系A
    地図座標系B
    center,
    zoom,
    rotate
    取得
    viewPoint2SysCoords
    SysCoords xys
    mercs
    center,
    zoom,
    rotate
    設定
    SysCoords xys
    sysCoords2Xys xys2Mercs
    sysCoords2ViewPoint xys2SysCoords mercs2Xys
    MaplatCore
    内部的にMaplatTin
    を5回利用
    内部的にMaplatTin
    を5回利用
    

    View Slide

15. Maplat
    MaplatCore
    Maplatライブラリ使い分け (2) 15
    前景地図
    OpenLayers
    背景地図
    OpenLayers
    地図表示制御
    座標系変換処理
    UI
    

    View Slide

16. Maplat
    MaplatCore
    MaplatSwitch
    Maplatライブラリ使い分け (3) 16
    前景地図
    OpenLayers
    背景地図
    OpenLayers
    地図表示制御
    座標系変換処理
    UI
    将来的にこの部分をMaplatSwitch
    として分割予定
    

    View Slide

17. Maplatの実現方法 17
    Overlay Switch
    ※地図APIとしてOpenLayersを使う場合は、既にMaplat/MaplatCoreで実現されており、
    オプションでOverlay/Switchは切り替えられるので、その他の地図APIを使う場合を想定
    前景地図
    地図API
    背景地図
    地図API
    地図API
    MaplatCore or
    MaplatSwitch
    リアルタイム制御
    MaplatCore or
    MaplatSwitch
    座標など変換
    表示地図切り替え
    

    View Slide

18. End
    User: kochizufan
    Github pages: https://code4history.dev/
    E-mail: kochizufan@code4history.dev
    18
    

    View Slide