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#1 2017-09-02 09:14:40

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 435
Website

ESRI imagery layer

This appeared in the OSM Weekly newsletter #371:

The satellite image layer “Esri World Imagery” can now also be used as a data source for mapping and is available in the OSM editors.

More info is available here: https://wiki.openstreetmap.org/wiki/Esri

Most of you probably know about this newly available imagery but if not, I want to inform you that this layer is vastly superior to Bing in many of the areas where I've checked (Alaska, Thailand [Nong Hoi]) and compared. It's easy to add in JOSM and is available in other editors as well.

Cheers,

AlaskaDave

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#2 2017-09-02 13:26:35

Tom Layo
Member
Registered: 2011-01-30
Posts: 72

Re: ESRI imagery layer

Hi Dave,

I used this imagery yesterday to map parts of Nakhon Si Tammarat that up to now had no images of any sort. It is only good to Z 17 there, and has the usual alignment problems. I have a spread sheet of areas covered by cloud, and have started going through them. Lots were already done by FB!

My work is pretty myopic, I just concentrate on one little area. Are zoom levels greater than 17 available on Esri?

There seems to be an embarrassment of sources of imagery lately. A big consortium of European car mfg companies recently bought a mapping company for billions. They all want as much data as possible for their car map GPS systems and maybe selfdriving cars. I don't know about the big picture here, except that is very big. Will try to do new thread.

In short, I always wanted to be making maps for the little guys. Any ideas?

Best Wishes!

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#3 2017-09-03 01:08:08

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 435
Website

Re: ESRI imagery layer

I haven't experimented with zoom levels but have come across some minor alignment issues. Like other satellite imagery, it helps to have some GPS trace data to better align it.

In Alaska, where I've been doing the bulk of my OSM work lately, the clarity of the imagery in some areas is amazing. I can see footways in the tundra, and plant life on the surface of certain ponds. After all the conversations about DigitalGlobe and how to help their FB group be successful, this ESRI imagery comes along and blows all the competition out of the water.

Thanks to those responsible for persuading ESRI to allow us the use of this superlative resource.

Aside: Might it be time for another gathering of Chiang Mai based mappers?

Last edited by AlaskaDave (2017-09-03 01:08:28)

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#4 2017-09-30 04:22:51

Russ McD
Member
From: Hereford & Chiang Mai.
Registered: 2011-04-17
Posts: 289

Re: ESRI imagery layer

The ESRI is good, but in many parts of Thailand, the Digital Globe imagery seems to go down two more zoom levels. Of course it varies by region, and sometimes the Std is actually better than the premium DG imagery.
Its a real mishmash at times, but a vast improvement on what we had before.... guess the answer is to keep swapping backgrounds with each new area, to find the best.

With regard to a meetup, I'm here until the 4th Oct, then away until early November.  Happy to meet anytime except Friday evenings ! big_smile

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#5 2017-09-30 08:34:24

AlaskaDave
Member
From: Homer, Alaska ; Chiang Mai
Registered: 2013-09-21
Posts: 435
Website

Re: ESRI imagery layer

Yes, that is quite true. Afer using the new layers for a while now, I agree that both varieties of DigitalGlobe imagery can be better than ESRI in certain areas. Now, I always load all of them, including Bing, and pick the best to use in my mapping. It seems that our old standby, Bing, is now often (always?) the odd man out. I'm guessing that the Bing imagery was mostly derived from DigitalGlobe in the past. I agree that at times the DigitalGlobe standard is better, other times the premium. As you say, it's a mishmash.

Also, initially, when using the ESRI imagery I was often unable to zoom in far enough to accurately draw ways. I could see objects very clearly but as soon as I zoomed in, the dreaded "No imagery available" message would appear and the screen would turn gray. I emailed Stephan asking him about adjusting the zoom level, which is a trick he had shown me a couple of years ago, and his tip worked. I replaced the "22" in the default ESRI World Imagery URL with the "17" you see in the following URL in JOSM's WMS/TMS preferences:

tms[17]:https://{switch:services,server}.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/tile/{zoom}/{y}/{x}

Now, I can zoom in so far that the image gets grainy but at least I can use it to draw ways. The offset issue mentioned earlier is real too. My guess is that the new imagery may actually be aligned correctly but the discrepancies are due to parallax. Perhaps they arise because the photographs were taken at different altitudes, I dunno. Anyway, I'm not sure how to get the same result in Potlatch or iD but this works for me.

I've used that same trick in the Bing URL as well replacing the "22" with "16":

bing[16]:http://www.bing.com/maps/

As always, YMMV

Last edited by AlaskaDave (2017-09-30 08:45:06)

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