On 1/26/2015 4:40 PM, zach cruise wrote:
On 1/25/15, Max Demars <burton449...@gmail.com> wrote:
I dont know if you are using Openlayers 2 or 3 but both has points
clustering strategies at client side:
see: http://openlayers.org/en/v3.0.0/examples/cluster.html
from http://openlayers.org/en/v3.0.0/examples/cluster.js, it is
randomly creating points. what if it had to load points already
created in memory? can ol2 (or 3) similarly cluster a 200 mb geojson
file?
or this: http://stackoverflow.com/a/6642203
On 1/25/15, Phil Scadden <p.scad...@gns.cri.nz> wrote:
On 24/01/2015 11:01 a.m., zach cruise wrote:
any real world ideas?
In real world, processing a million points in a browser doesnt happen.
JS is slow, download time is slow, execution environment in a browser is
extremely limited. (in my experience, doing more than 1000 points of
geometry is unacceptably slow in single threaded). Easiest approach for
doing this in a browser begins with figuring how not to have vector
data.
i want to avoid maptiler but what are the options for creating custom
tiles in ol?
On 1/25/15, Stephen Woodbridge <wood...@swoodbridge.com> wrote:
On 1/25/2015 4:03 PM, Phil Scadden wrote:
On 24/01/2015 11:01 a.m., zach cruise wrote:
any real world ideas?
In real world, processing a million points in a browser doesnt happen.
JS is slow, download time is slow, execution environment in a browser is
extremely limited. (in my experience, doing more than 1000 points of
geometry is unacceptably slow in single threaded). Easiest approach for
doing this in a browser begins with figuring how not to have vector
data. If this is an offline application, you want to look at local
server or local database. If you want to go extreme, then maybe look at
html5 web worker api to go multithreaded but I suspect you are up for
some pretty major rewrites of OL.
I would concur with this.
What is the basis for the requirement to do all this in the browser?
Is it an online or offline application?
online
If you have a million points, they can't all be displayed on the screen
at the same time or I would expect that they would all overlap to the
point that you would be hard pressed to display them all in a useful
manner where the user could differentiate them.
If you are displaying a subset then why not load just the ones you need?
using something like the bounding box strategy.
agree. but how does clustering happen with a 200 mb geojson file?
doesn't it need to load everything in memory first? if it is chunked,
how does ol know what chunk to call next (or asynchronous streaming of
vectiles as max said.
http://mattmakesmaps.com/blog/2013/10/09/tilestache-rendering-topojson/
uses a postgis backend that i can't use)?
Ok the idea behind vector tiles is that you do not load the whole 200mb
geojson file, you break it into smaller regular tiles like google raster
tiles for maps. Each of these has a name that maps to its extents and
these are loaded as needed based on your view extents. and they can
cached by the browser if they are static.
And for zoom levels you might create tiles, that are pre-clustered, so
as you zoom out the tiles are already in a clustered geojson format, so
you only display the clustered points, but each of these has all the
underlying data or statistics that you need. This obvious assume that
you have some what to tile your 200md geojson file into smaller regular
tiles, and that you have some way to pre cluster you tiles if you want that.
-Steve
On 1/26/15, Umberto Nicoletti <umberto.nicole...@gmail.com> wrote:
http://gis.stackexchange.com/questions/18572/openlayers-alternatives-supporting-more-client-side-features/18591#18591
this talks about a timer and filtering the visible points server-side
by configuring a strategy option to the vector layer. i can't filter
server-side, just have a 200 mb geojson to map.
On 1/26/15, Phil Scadden <p.scad...@gns.cri.nz> wrote:
Use the OL3/Cesium(WebGL) stuff like Bart said. Using the Cesium 3D
engine,
you can display 5-10million+ points using the Cesium pointGeometry branch
Count me skeptical, but I can see the WebGL might render point much
faster than drawing on a canvas - once you have got the points into
memory in the first place. Downloading as json and then interpreting
this into memory for 1M points is going to be slow. I note big data
going to cesium like terrain server support or 3D models are in packed
binary formats instead with json shell and are passed directly to host
graphics subsystem. If you can organize your data like that, you are
good to go but I am not sure you can then leverage advantages of vector
formats in openlayers.
agree with phil. dom ready takes 15 sec.
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