I wrote a POLYGON geometry column to my cassandra table, and everything looks fine in the Geoserver admin configuration as far as configuring the data store and layer for the GeoMesa feature. However, when rendered, the polygon scale is extremely small, especially when the map is first rendered in a zoomed-out mode. The zoom scaling is so small on the polygon that it is virtually invisible when the map is first rendered. Is there anything that can be done to adjust the zoom scaling? As you zoom out I believe the image should shrink, but still be visible at some cutoff zoom level.
Images attached.
Thanks.
Scale 1:24477405
Scale 1:1529838
You can use SLDs (styled layer descriptors) to draw the polygon at different zoom levels. See this gisexchange post for an example (using points). There are more examples of polygon styling in the geoserver docs.
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This might be a stupid question but I'm stuck and can't get passed it. I'm making a isometric game and I have my map built using tiles, I just followed this tutorial to build the map, http://www.binpress.com/tutorial/creating-a-city-building-game-with-sfml/137. But now I don't know how to add character sprites. Do I have to add these sprites using tiles as well or do I just draw the the sprites into position of the screen. Any help would be much appreciated.
As far as I can tell from the engine, just follow the "Textures and Animations" guide and draw the Animation to the screen after you have drawn the tiles. This isn't a complicated engine, so you are only working with 2D sprites being drawn to the screen (the 3D effect is merely tricks of painter's algorithm to make it work...there is no z-axis from what the tutorial indicates)
The depth is done by the order of tile rendering
The same goes for objects,players,etc... Let assume plane XY is parallel with the ground and Z axis is the altitude. Then your grid would be something like this (assuming diamond shape layout):
Order of rendering
You have to handle object,players and stuff sprites in the same way as tiles (and in the same time). so you should render all cells in specific order dependent on your grid layout and sprite combination equation. If your sprites can overwrite already rendered stuff then you should render from the most distant tiles to the closest to the "camera". In that case the blue direction arrow on above image is correct and Z axis should be increasing in the most inner loop.
So now if you got any object,player or stuff placed in cell (x,y,z) then you should render it directly after the cell (x,y,z) was rendered prior to rendering any other cell.
To speed up is a good idea to have objects and players in your tile map as a cell. But for that you have to have the tiles in the right manner and also your map representations must be capable of doing so.
I've a point cloud object in Three.js with thousands of 2d geo location points. They are laying on the same z plane.
Currently, with using normal blending with semitransparent points, I can achieve the first result of the image below, blending the colors of the overlapping points to achieve an alpha value of 1.
I'm interested to achieve the saturation of the second image where overlapping points saturate to white. Is it possible using only blending? or I need something else like Effect Composer?
Thanks
I used google maps to make a project that records flood incident in a certain area. I used polygons to represent those floods, since the project is for planning purposes it is required of us to output all the historical flood data into a single map. My problem is if I simply just output all polygons, it would look messy and cluttered. So I was wondering what method I could use to represent these polygons in a better fashion. We were advised to use heatmaps, but I can't seem to find tutorials on how to make polygons into heatmaps. Any suggestions would be appreciated. Thanks!
To turn a polygon into a heatmap, render the polygons in black with high transparency into a white bitmap. This should result in a grayscale image, which will be darker where many polygons overlap. Then convert the gray values of the bitmap into the hue value of a corresponding semi-transparent color bitmap.
Why did the rendering look messy? Did you try rendering filled polygons with high transparency and no borderline? That should result in areas that are more prone to flooding being more "highlighted".
I'm using KineticJS to allow users to free hand drawing shapes on canvas and I am successfully able to zoom in/out canvas stage by setting scale.
Challenge:
Am not getting the updated scaled coordinates values after zoom in/out. Any suggestion would be appreciated.
As far as I know, the coordinates don't get scaled, because the only thing you are changing with the 'setScale()' method is the zoom.
So, if you want to know tne coordinates in the scaled stage you probably have to store the scale amount in a variable and when you need a coordinate after scaling, you simply multiply the original shape coordinate with the scale of the stage.
This would be my approach, not sure if there is any other way to do this ;)
I am developing a Map App for our school. Our school provide me its own map image and coordinate information. So I want use my map image as the source of map and accord to user's location to show a point in the map image. Can anybody gives me some advice?
Thanks in advance.
There are 2 ways:
It is possible to change the source of the map-tiles (e.g. from Bing to say Nokia or Google) of the Map Control. However, for this to work, it is important that map-tiles source implements mechanisms like quadkeys (e.g. see this). Therefore, to answer your question if you would like to use the Bing Map Control with your school's map so that you can leverage the positioning features of the control, it would require that you have a map-tile server properly designed in order to achieve this. AND, there might be some legal issue with altering the Bing Map control if i am not mistaken.
However, given that you are suggesting an image of the map and then doing positioning, then i would suggest that it can be as easy as you calibrating the pixel X-Y coordinate system on the map with that of the geo-coordinate provided by the geo-watcher. Then, in your code you could do a simple mapping between these 2 systems and then draw something on top of the image. For this part you could use a writeablebitmap or simply use the fact that you can overlay UI controls with silverlight. So, for the latter have a canvas with the an image of the map of your school and then on top of that canvas you can have an <image> representing the device and change its top-left coordinate wrt to the canvas.
So, in summary, as the geo-watcher gives geo x-y coordinates to your code, there is mapping function to the pixel X-Y (which you have pre-calculated) and use that XY to position an overlay <image> or draw some "pin" on a writeablebitmap where you have previously draw the image of the map of your school. Things get complicated with this approach when you want to have zooming as well but, this solution is easily scalable.
Does this help clear things a bit?
Answering 2nd question in comment below:
Yes you can zoom in and out of the canvas but, you would have to program it yourself. The control itself, the canvas does not have this capability. Hence, you would have to recognize the triggers for a zoom action (e.g. clicking on the (+) or (-) buttons or, pinch and stretch gestures) and react to that by re-drawing on the canvas a portion of the region on the canvas so that now that regions stretches over the entire canvas. That is, zooming. For instance for the zoom in case: you would have to determine a geometrical area which corresponds to the zoom factor and is in ratio to the dimensions of the canvas object. Then, you would have to scale that portion up so that edges and empty spaces representing walls and spaces between them grow proportionately. Also, you have to determine the center point of that region which your fix on the canvas so that everything grows away from it. Hence, you would be achieving a appropriate zooming effect. At this point you would have to re-adjust your mapping function of geo-coordinates to pixel XY so that the "pin" or object of interest can be drawn with precision and accurately on the newly rendered surface.
I understand that this can appear quite intensive but, it is straightforward once you appreciate for yourself the mechanics of what is required.
Another easier option could be to use SVG (Scalable Vector Graphics) in a Web-Browser control. Note that you would still require the geo-coordinate to pixel-xy system. However, with this approach you can get the zooming for free with the combination of SVG (which have transformation capabilities for the scale up and down operations) and Web-Browser which enables you to render the SVG and does the gesture handling of zooming in to the map. For that, i believe that the cost of work would be in re-creating the map of your school which is in bitmap to SVG. There are tools like Inkscape which you can use to load the image of your map and then trace the outlines over it. You can then save that outline document as an SVG. In fact, i would recommend this approach to your problem before tackling the Canvas method as i feel that it would be the easiest path for your needs.