[686] | 1 | .. _ogr_base_vect_ops: |
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| 2 | |
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| 3 | Building blocks presentation - Using OGR and PgRouting based Web Services |
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| 4 | =================================================== |
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| 5 | |
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| 6 | .. contents:: Table of Contents |
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| 7 | :depth: 5 |
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| 8 | :backlinks: top |
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| 9 | |
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| 10 | Introduction |
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| 11 | ------------------ |
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| 12 | |
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| 13 | In this section, you will use basic ZOO-Services : ``Buffer``, |
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| 14 | ``Intersection`` and ``DifferencePy`` which use OGR and psycopg Python modules. |
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| 15 | The intended goal of this section is to present and interact with your new building blocks before chaining them in the next section. |
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| 16 | |
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| 17 | First of all, you should use the following links to access the user |
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| 18 | interfaces and interact with your services, the first one is used to |
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| 19 | access basic spatial-tools demo client interface and the second to |
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| 20 | access the routing application : |
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| 21 | * `http://localhost/zoows2013-demo/spatialtools-py.html <http://localhost/zoows2013-demo/spatialtools-py.html>`__ |
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| 22 | * `http://localhost/zoo-ws2013/ <http://localhost/zoo-ws2013/>`__ |
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| 23 | |
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| 24 | Services Provider and configuration files |
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| 25 | ---------------------------------- |
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| 26 | |
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| 27 | First you may verify if the ZOO-Services are available from your current setup. |
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| 28 | You can take a look at the ``Buffer.zcfg``, ``Intersection.zcfg`` and |
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| 29 | ``DifferencePy.zcfg`` to get details about parameters. |
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| 30 | As you can see from the ZCFG files, you will use ZOO-Services provided by the |
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| 31 | ``service`` Python service provider. So if you want to modify the Python code |
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| 32 | you will have to edit the corresponding file (so ``service.py``). |
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| 33 | You are invited to use similar requests as the one used in previous |
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| 34 | sections to learn about each services individually. |
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| 35 | |
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| 36 | The Buffer Service |
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| 37 | ------------------------------------ |
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| 38 | |
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| 39 | First click on a street then once the street is displayed in blue, click the |
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| 40 | 'Buffer' button on top, you should get similar result as displayed in the following. |
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| 41 | |
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| 42 | .. image:: ./images/Buffer_Level_15.png |
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| 43 | :width: 650px |
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| 44 | :align: center |
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| 45 | |
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| 46 | Since version ZOO-Project 1.2.0, you can run automatically some basic tests to |
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| 47 | make sure that you wrote a correct ZCFG file and your service is validating. |
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| 48 | |
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| 49 | .. note:: the current testing is really simple and should be adapted to each Services |
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| 50 | Provider, mainly to define input names. |
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| 51 | |
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| 52 | You can use the following command: |
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| 53 | |
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| 54 | .. code-block:: bash |
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| 55 | |
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| 56 | cd /home/user/zoo/testing |
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| 57 | ./run.sh http://localhost/cgi-bin/zoo_loader.cgi Buffer |
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| 58 | |
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| 59 | |
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| 60 | .. note:: During or after the test run, you can take a look inside the ``tmp`` directory |
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| 61 | which contains both the XML requests send to the ZOO Kernel (``*1.xml``) and the |
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| 62 | responses it gave (``output*.xml``). |
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| 63 | |
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| 64 | The Intersection Service |
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| 65 | ------------------------------------ |
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| 66 | |
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| 67 | Using the same client interface as before, once you get a Buffer, you can then |
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| 68 | select a street intersecting the Buffer geometry to compute intersection by clicking on the Intersection button. |
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| 69 | |
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| 70 | |
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| 71 | .. image:: ./images/Intersection_Level_15.png |
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| 72 | :width: 650px |
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| 73 | :align: center |
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| 74 | |
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| 75 | |
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| 76 | The DifferencePy Service |
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| 77 | ------------------------------------ |
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| 78 | |
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| 79 | Using the same instructions as for Intersetion, you can get the following result. |
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| 80 | |
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| 81 | .. image:: ./images/Difference_Level_15.png |
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| 82 | :width: 650px |
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| 83 | :align: center |
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| 84 | |
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| 85 | |
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| 86 | The Routing and Profile Services |
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| 87 | ------------------------------------ |
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| 88 | |
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| 89 | First click on the blue flag then place your starting point on the |
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| 90 | map, do the same with the red flag to get the shortest path computed |
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| 91 | by the dedicated service and then display its profile. Note that when |
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| 92 | you pass the mouse over the profile display then you will see its |
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| 93 | corresponding position displayed on the map. You can also click on a |
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| 94 | specific step in your path to get the corresponding line displayed. |
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| 95 | |
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| 96 | .. image:: ./images/Routing_Basic.png |
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| 97 | :width: 650px |
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| 98 | :align: center |
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| 99 | |
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| 100 | If you take a look in the file: ``/usr/lib/cgi-bin/routing/do.zcfg`` |
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| 101 | you may notice something new in the supported format which is |
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| 102 | reproduced here after. |
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| 103 | |
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| 104 | .. code-block:: guess |
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| 105 | |
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| 106 | <Supported> |
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| 107 | mimeType = image/png |
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| 108 | asReference = true |
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| 109 | msStyle = STYLE COLOR 125 0 105 OUTLINECOLOR 0 0 0 WIDTH 3 END |
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| 110 | useMapServer = true |
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| 111 | extension = json |
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| 112 | </Supported> |
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| 113 | |
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| 114 | The ``mimeType`` is defined as ``image/png`` and there is two new |
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| 115 | parameter which are both optional: |
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| 116 | * ``useMapServer``: which make you able to inform the ZOO-Kernel |
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| 117 | that it have to use MapServer to publish your result as WMS / WFS or WCS (this last |
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| 118 | won't be used in this workshop) rather than simply storing the |
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| 119 | result as a file. |
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| 120 | * ``msStyle``: which let you define your own MapServer ``STYLE`` block definition. |
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| 121 | |
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| 122 | When you need to access a result many time or for different purpose |
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| 123 | accross other services then it is really useful to ask ZOO-Kernel to |
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| 124 | publish your result as WMS, WFS or WCS. |
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| 125 | |
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| 126 | Note that no modification of the code of the do service was required |
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| 127 | to handle automatic pubilcation of the result as it is a vector format |
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| 128 | supported by OGR, only modification of the zcfg was required. |
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| 129 | |
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| 130 | This routing example is here to illustrate how easy it is to publish |
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| 131 | your result as WMS, WFS or WCS ressource. Indeed, when your routing |
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| 132 | service was called, ZOO-Kernel published the result as WMS and WFS |
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| 133 | ressources which was both used first for the UI purpose, the WMS to |
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| 134 | display the resulting path on the map, the WFS for displaying details |
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| 135 | about each steps. The WFS protocol is also used as the input value |
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| 136 | for the profile computation. So, the computation was run once |
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| 137 | and accessed three times for different purposes and from different |
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| 138 | clients. |
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| 139 | |
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| 140 | For more informations about the MapServer support, please refer to `the |
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| 141 | official ZOO-Project Documentation <http://zoo-project.org/docs/kernel/mapserver.html>`_. |
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| 142 | |
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| 143 | Conclusion |
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| 144 | ------------------------------------ |
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| 145 | |
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| 146 | Now you know this three services, and you get a simple interface to interact |
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| 147 | with your MapServer WFS and your ZOO-Project WPS Servers, you are ready to use |
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| 148 | the Services in a different way, by chaining them using the JavaScript ZOO-API to build |
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| 149 | more complexe and powerfull services. |
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