[GIS] Generate tiles with EPSG:4326 projection using Mapnik

mapnikopenlayers-2postgis

I'm trying to generate tiles from a PostgreSQL database that contain OpenStreetMap (OSM) data in EPSG 4326. I used the scripts generate_xml.py and generate_tyles.py provided by mapnik-stylesheets.

The final result is not correct, the overlapping of the layers is wrong.
The client code is JavaScript and uses the OpenLayers library.

var danube = new OpenLayers.Layer.XYZ(
 "OSM",
 "http://localhost/osm/${z}/${x}/${y}.png",
 {sphericalMercator: false,
   numZoomLevels:11,
   buffer: 0,
   isBaseLayer: true,
   projection:"EPSG:4326"
);

I think that the client code is correct but the generation tiles with Mapnik is not correct. Indeed, the tiles generated have an overlaps and are not shown correctly.

Best Answer

The generate_tiles.py script only works for mercator. For a more flexible tiling system that supports Mapnik and any projection see MapProxy and for extra details see the mapnik-users thread on this type of setup: https://groups.google.com/forum/#!msg/mapnik/YBqjwv4YU0w/TVD0KqYxeG4J

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[GIS] Problems with features, popups and strategy with OpenLayers

you can catch your opened(active) popup with this way:

map.popups[a]

you can change so update its content:

map.popups[a].contentHTML = 'Test Content';
map.popups[a].redraw();

or

map.popups[a].setContentHTML = 'Test Content'

you can show or hide your popup:

map.popups[a].show();
map.popups[a].hide();

you can update position of your popup:

map.popups[a].lonlat.lon = 10;
map.popups[a].lonlat.lat = 10;
map.popups[a].updatePosition();

for openlayers cluster you should check out Cluster Strategy Example here. Only one thing you should do is that define fillColor or externalGraphic for your cluster.

          var style = new OpenLayers.Style({
                pointRadius: "${radius}",
                fillColor: "${getColor}",
                fillOpacity: 0.8,
                strokeColor: "#cc6633",
                strokeWidth: 2,
                strokeOpacity: 0.8
            }, {
                context: {
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As the last question, i dont understand very well what you want? but try to use removeFeatures instead of destroyFeatures....

i hope it helps you...

[GIS] Mapnik renders only “blank” tiles

I can't give you a response as I don't see what's wrong in your config. I've made a similar stack (Postgis + Mapnik + Mapproxy + Apache).

I see that your zoom=1 works. I think I could be :

a broken CartoCSS when you call higher zoom
a source file (ex. a .SHP) that must appears in higher zoom but is not accessible by renderd (or it has no read rights)
a problem in TileStach. I don't know it, but with MapProxy, we had memory issues with tiles that were too big (2048x2048, because we wanted to make tiles for 4k screens). Look a its logs perhaps.
another thing, I'm relatively new in GIS too !

I suggest you to try with a simpler stack, like me in case of blank or pink tiles :

Use a tested project that have already worked (I use https://github.com/mapbox/osm-bright)
Ignore Tilestach and connect your client directly to mapnik (renderd). The cache complicates the debugging process, don't forget to empty it each time you updates your CartoCSS project.

Sorry for that "blurry" response!

Best Answer

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[GIS] Problems with features, popups and strategy with OpenLayers

[GIS] Mapnik renders only “blank” tiles

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