Openlayer plugin performance ideas?

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Openlayer plugin performance ideas?

forkandwait
Hi all,

I have a project in which I basically have two large base maps -- an openlayers
plugin map from google (hybrid), and a postgis vector layer with all the census
blocks for the entire state of Oregon.  I zoom in and out of the map looking at
various attributes in the block to see if they match buildings shown in the
areal image (specifically, whether large group quarters numbers in the block
correspond to large buildings in the block as well).

Often I will query the block layer to constrain it to a given city and with
blocks that have a certain attribute ("cityname10='Newport' and gq10>=10"), and
zoom to those blocks using the attribute table.  Sometimes I just do a
constraint like gq>=100 and look at the whole state.

The block layer only renders when the scale is 25000:1 or less.

This works fine as it is, but it can be a little bit pokey when the openlayers
image is open. If I turn off the image, it is darn fast.  I would like to try
scale dependent rendering, but I can't get a properties dialogue.

Does anybody have any ideas on how to speed this up, and still do it on a
statewide scale (ie I don't want to download a bazillion image files, if I can
avoid it)?

It works pretty well as it is, I just want it faster. ;)

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Re: Openlayer plugin performance ideas?

mayeulk
>  I don't want to download a bazillion image files
Anyway Google maps terms of use probably forbid this. (Same for Bing?).
You may try with Bing tiles, they have static tiles that are easier to get and their banning policy is, I believe, not as strict, which may be easier to work with.

And / or  you may try to see if you can cache the tiles using a local proxy server. The code given in the following page works very well for caching OSM tiles with the OpenLayers plugin in QGIS:
http://wiki.openstreetmap.org/wiki/ProxySimplePHP

Finally, all would be faster if the plugin could display the image even when there are a few tiles missing. I filed a ticket for this some times ago. If you have developing skills you may try to help here.

Mayeul


----- Mail original -----
De: "fork" <[hidden email]>
À: [hidden email]
Envoyé: Mardi 15 Mai 2012 17:59:42
Objet: [Qgis-user] Openlayer plugin performance ideas?

Hi all,

I have a project in which I basically have two large base maps -- an openlayers
plugin map from google (hybrid), and a postgis vector layer with all the census
blocks for the entire state of Oregon.  I zoom in and out of the map looking at
various attributes in the block to see if they match buildings shown in the
areal image (specifically, whether large group quarters numbers in the block
correspond to large buildings in the block as well).

Often I will query the block layer to constrain it to a given city and with
blocks that have a certain attribute ("cityname10='Newport' and gq10>=10"), and
zoom to those blocks using the attribute table.  Sometimes I just do a
constraint like gq>=100 and look at the whole state.

The block layer only renders when the scale is 25000:1 or less.

This works fine as it is, but it can be a little bit pokey when the openlayers
image is open. If I turn off the image, it is darn fast.  I would like to try
scale dependent rendering, but I can't get a properties dialogue.

Does anybody have any ideas on how to speed this up, and still do it on a
statewide scale (ie, if I can
avoid it)?

It works pretty well as it is, I just want it faster. ;)

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Re: Openlayer plugin performance ideas?

forkandwait
In reply to this post by forkandwait

fork <forkandwait@...> writes:

> Does anybody have any ideas on how to speed this up, and still do it on a
> statewide scale (ie I don't want to download a bazillion image files, if I can
> avoid it)?

For great speed, I am now using the OSM layers for streets and landscape.  It
doesn't give you that satellite detail, but if I turn on the satellite only when
I need to look at buildings (as opposed to orient myself), it speeds up the
process.

Mayeul -- I wish I had the dev skills to help with the plugin -- I am
overcommitted these days, and can only offer moral support and kudos to the
excellent plugin

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