Switch OpenStreetMap layers so pixel perfect in the center of the zoom level about geojs

[jbeezley]

I think this is resolved. There is no configuration for adjusting the supersampling, but resolution has been bumped up about as much as is reasonably possible.

[jeffbaumes]

When looking at

http://opengeoscience.github.io/minerva/

I am seeing very low-res data when zooming on a large-resolution monitor in full screen mode. This seems to be the highest-resolution image I can get:

Is the transition point percent-of-window based instead of pixel-based? When I have a much smaller browser window I can get tiles that more closely match pixels and it looks better.

[jbeezley]

I think you're right. The initial view depends on the vertical size of the canvas. We should really make it so that the scale (pixels per gcs unit) is independent of the canvas size at each zoom level.

[aashish24]

@jeffbaumes what you are seeing is the artifcat of sampling which is not matching up with the image resolution. One of the reason is that we doing it in pespective mode. I will be looking at this issue more closely once I am done finishing up some clean up work in webgl world which may help with this as well.

[jeffbaumes]

@aashish24 I do not think this is just sampling, images would look clearer with higher-res tiles. For example look at the tip of a yellow triangle zoomed below. Image pixels are ~4 screen pixels.

[aashish24]

Are you talking about gradient (like anti-aliased)? That would be sampling artifact as well as its trying to sample the data for those pixel locations. Or may be something else you are referring to which I didn't get int this image.

[jbeezley]

With #318 in, the image quality is much better. Have a look at the updated examples page. This causes the tile levels to be chosen correctly according to the viewport size. As @aashish24 has noted in the PR, there are some artifacts due to having a non-orthographic projection.

http://opengeoscience.github.io/geojs/examples/index.html

[jbeezley]

With #421, I think we can finally close this for real. I put up a demo here using the parallel projection and discrete zoom to display the tile images without any interpolation. Note to touchpad users, the zoom interaction is overly sensitive (issue #424).