I'm trying to setup GeoServer to display 2 data stores. Both are full Earth tile sets, 1 for Day and 1 for night. The imagery is 200m which roughly translates to 2x 50 1.2GB GeoTiffs. For context, the application this a museum exhibit that simulates the view from the Space Station. Tiles need to load quickly and often times for large areas if we're going to provide an oblique view (looking over the horizon). We're using CesiumJS for the renderer which has support for most of the imagery provider standards out there.
Steps I've tried already tried:
ImageMosaic. I can't load Zoom Levels 0-4 without the server running out of memory. At the further zoomed out levels I get a stupendously blurry image and it takes minutes for it to return the actual high-resolution tiles. I have caching on and I've even run the seeding process.
ImagePyramid: Using GDAL I built an ImagePyramid with 11 layers for each of the tile sets. This seemed to help a little, but seems to have capped the resolution greatly.
At this point I can only assume I need to do some fancy hybrid configuration of the 2, but I'm at a loss for where to actually start or if there is actually just a defacto way these sorts of configurations are handled.
Got anyone that is interested the solution that worked best is to merge the tiles together and use gdal2tiles to create a TMS server.
Related
I want to begin working on a big sandbox game with lots of oceans and islands. This will obviously require a very big map.
I've spent the last couple days researching the best methods on doing this and so far have figured out that
I need to split the terrain into tiles/chunks.
I need to have the player only load those tiles/chunks that are closest to them and unload those further away.
That being said. I would rather avoid flooding my game with a bunch of assets and want to kind of handle things on my own and hard code these systems in myself.
Some questions,
Can I just create a massive 20k x 20k terrain using Unity's built in terrain editing system and then worry about splicing and loading/unloading the tiles later?
or do I need to build my big terrain in an alternative program and import my terrain in then handle the splicing and loading situation?
Also, when it comes to multiplayer. I assume I would just need to basically do the same thing just for each client?
I would appreciate any other tips or guidance on doing this as well. Thanks.
Splitting into multiple chunks but ones that arent too small seems to be the better option, maybe like 4 quarters, that way you are not flooding with assets, you would disable all quarters except the one the player is in.
The problem with making a big terrain is, while you could get a tool from the asset store to split ur terrain later, you will get into the headache of resolutions and sizes and overall I guess its better to split it into 4 pieces or a bit.
You would have a trigger point where you want the game to load the terrain, and depending on which trigger point the player entered you would load the corresponding terrain piece.
For multiplayer, you would do the same thing for each client, making your big terrain as 4 smaller terrains and then loading the corresponding quarter. Tell me if I missed something.
I am using iText PDF 5.4 along with the Java2D interface (java.awt.Graphics canvas), and I have a severe problem with gradients.
I am painting many rectangular shapes whose paint is a LinearGradientPaint. This results in large files (e.g., 10 MB), and trying to open the results in e.g. Preview.app brings the computer to total halt. The problem seems to be memory usage, because the first dozens of boxes paint rather quickly and then performance slows down somewhat linearly with more boxes, which means that for a typical page it takes >10 minutes to open.
Adobe Acrobat is also slow but at least it takes some 4 or 5 seconds instead of several minutes.
Is this a bug of iText? Is there a setting or tweak in iText that controls the representation of gradients? I guess it decomposes them into hundreds of separate paint commands instead of using a direct gradient component (if that exists—I know it exists in SVG, but PDF I have no clue).
The condition is that I stay in the awt.Graphics, I cannot rewrite my rendering code to not use Java2D.
An alternative idea would be to use Apache Batik and output to SVG instead. There is an example that shows how to enable the correct transcoding of LinearGradientPaint to the SVG equivalent.
EDIT: There seems to be a new Java2D-to-SVG library JFreeSVG. Recent changes indicate that gradients are implemented.
background: i am developing a real-time multiplayer html5 canvas game using kineticjs which primarily will be played on MOBILE PHONE BROWSERS. There's a lot going on in the game such as socket communication with the server every second, redrawing and animations using kineticjs based on the server response and all this on top of a heavy graphic interface. The game functions well in desktop browsers however is SLUGGISH on mobilephones. So, I need to find all the ways in which the code can be optimized.
My questions,
lets say I need to redraw a particular part of the screen based on a server response that I just received from server, should I keep these need-to-be-redrawn elements in a separate layer, so that I need to redraw fewer elements. As in my case I need to redraw ever second, will this lead to performance improvement?
If the answer to the above is yes, then what is the optimal number of layers in which I should divide my layout. I ask this because I have a lot of different parts on the screen that need to be redrawn based on different server responses (although not all at the same time), if all these need to be put in separate layers, I need to know how far I can stretch the logic above, for example can I have 10 different layers without sacrificing the performance which is the aim of all this exercise anyway.
Eric Rowell (creator of KineticJS) has done some stress tests here: http://www.html5canvastutorials.com/labs/html5-canvas-kineticjs-drag-and-drop-stress-test-with-1000-shapes/
And he says this:
"Create 10 layers each containing 1000 shapes to create 10,000 shapes. This greatly improves performance because only 1,000 shapes will have to be drawn at a time when a circle is removed from a layer rather than all 10,000 shapes."
"Keep in mind that having too many layers can also slow down performance. I found that using 10 layers each made up of 1,000 shapes performs better than 20 layers with 500 shapes or 5 layers with 2,000 shapes."
So your takeaway is that
1.Yes, multiple canvas layers which isolate different groups of redrawables is the way to go.
And,
2.To optimize the tradeoff ( overhead of multiple canvas’s vs simplicity of 1 canvas ), you need to test with your own particular code in the environments they will be operating within.
Good luck with your game :)
I am developing large geo location web site. There are over 2.5 million places to show on Google Map with markers and info window (when marker clicked).
I am using MarkerClusterer to narrow down the load of individual marker.
But, I am afraid if so much data in browser (JSON etc) would really kill the page.
Any suggestions to load on demand JSON by identifying the map bounds when panning is changed.
Any recommendations to resource also appreciated.
Have a look at Cluster I think it may do what you want:
Only the markers currently visible actually get created.
If too many markers would be visible, then they are grouped together into cluster
markers
You can look for a quadkey. A quadkey is perfect to reduce the dimension complexity and build clusters of the point of interest. There are many different methods like z curve, hilbert curve, peano curve. To further limit the constraints you can attach the cluster thing to the bounding box and the zoom level of the google maps.
There is a version of marker Clusterer that works for v3 of the google maps api, but that isn't the issue here. The issue is that you'd still be handling the underlying data in the browser with JS (2.5 million places retrieved thru JSON/AJAX). That is most likely too much, unless you're on a fast connection using the fastest computers with a lot of ram.
For those contemplating this issue on their own sites, keep in mind that more and more mobile devices are accessing these sites, and the javascript on such devices just can't handle nearly as many points. My own site broke with the latest release of iOS6, and now I have to accommodate by changing my js to an easier system load.
But to get back to the answer at hand, what you'll have to do is make a new ajax call whenever the map bounds change, and if the zoom goes too far out, you'll have to limit the number retrieved and implement some system to show the user that not all results are shown. My site uses a limit of 250, if I recall correctly, and shows a bounding rectangle around the locations (along with markerclusterer to cluster them). Before populating with real data, I did a test database of thousands and thousands, and this number seemed to be the best tradeoff of performance and information. (But that was before I went mobile and before v3 of the api). v3 is supposed to be more streamlined, but mobile devices are limited, so you'll have to test.
I am using marker clusterer plus library with a marker size cap of 200 and default zoom level 8. On zoom change or drag, another 200 markers will come on the map.
If you zoom-out the markers will be clustered and vice-versa.
I have about 5000 markers I need to render on Google Map. I'm currently using the API (v3) and there are performance issues on slower machines, especially in IE. I have done the following already to help speed things up:
Used a simple marker class that extends OverlayView and renders a single DIV element per marker
Implemented the MarkerClusterer library to cluster the markers at different levels
Render GIFs for IE, instead of alpha PNGs
Are there faster clustering classes? Any other tips? I'm trying to avoid server-side clustering unless this is the only option left to squeeze performance out of the system.
Thanks
I used a method that loads all the markers onto the page, and then listens for the map to finish panning.
When the map has finished panning, I first check the zoom level - if it's too high I don't display anything. If it's at an acceptable level, I then loop through the markers I have stored and see if they fall into the bounding box of the map. If they do, they get added. A second loop then removes any that have moved out of the view.
The highest number I've used is about 30,000 markers with this method, although I have it so you must be zoomed in quite far to see them. In areas of higher concentration of markers it's obviously a little slower but it's useable.
The solution mentioned above works for much higher number of markers. We use it for millions of GPS points at backend (including polygons etc). The only problem is some logic behind like proper caching of spatial queries, or fetching new results only, if user moves a map for more than X meters. There is a lot of work to make it done, but for viewing real high number of points, there is nothing better.
Marker clusteres are usually working at browser side, so these is still need to load all points at once - and this makes this method unusable for large numbers.
You can check it out at http://www.tixik.com/london-2354567.htm live (just click ,,plan a trip " and start planning. Just try to move a map, zoom in or out and all points will show/hide on map zoom/drag.