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niraD

Allow Challenge Caches based on authoritative third-party data sources

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9 minutes ago, thebruce0 said:

...I know what a contour line is. I meant for the context of challenge checking by region.

It is not secret how elevation data at PGC is determined. Here is the reference https://project-gc.com/Home/FAQ#4179902386

You may say that the database contains only measurements, but if you make the lookup for over 3000 feet elevation then you get a pattern from the database. As you get a pattern when you make lookup for over 30 degrees latitude. The edge of the first pattern is called contour line and the edge of the second pattern is called parallel.

We can try the Duck test for this problem.  https://en.wikipedia.org/wiki/Duck_test

If it looks like a pattern etc., then it probably is a pattern.

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31 minutes ago, arisoft said:

It is not secret how elevation data at PGC is determined. Here is the reference https://project-gc.com/Home/FAQ#4179902386

mhm... the initial data is from NASA. NASA has the altitude readings. PGC gets relevant data for the coordinate - that is, the 30x30m resolution (at best) altitude measurements that are available nearest the coordinate and determines an average (whether it's SRTM1, 2, 3 for descreasing resolutions), and that average is used as the geocache altitude.  A challenge cache will not be able to require a 'pattern' in the altitude values.  A CO won't be able to form an arbitrary pattern that a finder must qualify for using only altitude values.  Are there any altitude-qualification challenge caches that have published after the moratorium?  I think that question was asked somewhere recently, and if I recall there weren't; but I'm not positive.

The point is - county boundaries are literally determined by horizontal plane latitude and longitude coordinates.  Groundspeak has decided that is the only regional polygon boundary that is allowed for location-based challenges.  Altitude data is determined first by reading vertical ascension at specific points and, to my best understanding:  stored in an extensive database (eg, NASA's SRTM1/2/3), then for easy cross-reference the worldwide resource is made available containing these altitude readings. Sure, regional polygon data can be generated from these readings for some other use, but this topographical data is the source of readings by which an altitude at a GPS coordinate is determined.

In short, the way I understand PGC's calculation of altitude is this: 1] Input-> GPS coordinates; 2] locate nearest available altitude readings to the given coordinate from the various sources of data they have available; 3] determine average of the altitude data 4] return calculated geocache altitude.

From PGC:

Quote

The SRTM1 data has ONE measure point per 30x30 meters, and the SRTM3 data has ONE measure point per 90x90 meters. What this means, is that there is no measurement for every coordinate, and therefore not for every geocache location. So what we do is that we interpolate between the 4 closests values to get a weighted average for the geocache location.

 

Edited by thebruce0

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32 minutes ago, thebruce0 said:

In short, the way I understand PGC's calculation of altitude is this: 1] Input-> GPS coordinates; 2] locate nearest available altitude readings to the given coordinate from the various sources of data they have available; 3] determine average of the altitude data 4] return calculated geocache altitude.

Right. And the same method can be used to draw contour lines. Just use higher resolution than 0,1 miles and you can plot map where this method gives equal values.

Anyway, the idea behind this example is only to show that if you have some good idea, do not skip it just because it seems to be unallowed.Some ideas may be accepted.

Edited by arisoft

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19 minutes ago, arisoft said:

Right. And the same method can be used to draw contour lines.

Yes, but guaranteed you won't be able to publish a challenge cache requiring qualification within arbitrarily determined altitude contour lines. You will only be able, at best, if you're lucky, to require altitude ranges based on PGC lookup. That's it. Include any type of location boundaries in your qualification and it won't be allowed, because only counties, states and provinces, and countries are allowed for region boundaries.

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10 minutes ago, thebruce0 said:

Yes, but guaranteed you won't be able to publish a challenge cache requiring qualification within arbitrarily determined altitude contour lines. You will only be able, at best, if you're lucky, to require altitude ranges based on PGC lookup. That's it. Include any type of location boundaries in your qualification and it won't be allowed, because only counties, states and provinces, and countries are allowed for region boundaries.

There is no known limits. You can select any values for you challenge. Recently has been published a challenge for caches over 120m which value is not displayed in the PGC statistics chart.

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8 minutes ago, arisoft said:

Recently has been published a challenge for caches over 120m which value is not displayed in the PGC statistics chart.

GC? But I'm not concerned about altitude challenges. I don't see them as regional polygons, and I'm sure that's not what Groundspeak sees altitude as either.

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9 minutes ago, thebruce0 said:

But I'm not concerned about altitude challenges. I don't see them as regional polygons, and I'm sure that's not what Groundspeak sees altitude as either.

Let's assume that following is the official opinion from HQ despite that I can not verify the source.

Quote

Indeed, elevation is not on Geocaching.com. However, neither are DeLorme or
county data. We think elevation falls into the bucket with DeLorme and
counties. It's fairly standard to determine elevation based on lat/lon,
just as it's standard to determine counties or Delorme data with lat/lon
inforomation."

Everything in this snippet seems to be logical. You have to try to publish DeLorme challenge to get the ultimate answer for the question whether it is possible or not.

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I don't see how that's relevant. As I said, DeLorme is regional location-based polygon data. Altitude is not. Even so, Groundspeak has decided to explicitly only allow county data for regional polygons. Likely because it's government-determined whereas other regional boundaries have different authorities; who knows, I don't. Counties are allowed. Altitude is fundamentally different in its determination than that of the latitude/logitude gps boundaries of counties.

Edited by thebruce0

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1 hour ago, arisoft said:
1 hour ago, thebruce0 said:

I don't see how that's relevant.

Try harder!

Clearly you missed the rest of my comment. There was more than what you quoted.  DeLorme polygons (user-defined, and not accepted by Groundspeak) are not the same as altitude readings which are used to determine by averaging the altitude at a specific gps location.  Whether GS should allow DeLorme regions for challenge requirements is a different discussion than whether Groundspeak should allow altitude ranges as a challenge requirement.

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To clarify, altitude-based challenges are permitted worldwide. It is not a matter of reviewer discretion, it is a matter of following guidance provided by Geocaching HQ.  If an altitude-based challenge is turned down, it is for other reasons (for example, "find 100 caches with an altitude between 1032 feet and 1034 feet" or "find a cache with an altitude of X or greater on 30 consecutive days").

Altitude-based challenges are not "pattern-based" challenges, whatever that means.  They are based on estimated data points, not "contour lines."

Since altitude-based challenges are allowed worldwide, and are not based on artificial polygons like a DeLorme grid, it would be best to get the discussion back on the topic of what people wish to see that is currently not allowed.

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Thanks.  So as to the thread title: "Allow Challenge Caches based on authoritative third-party data sources" I think the question strictly speaking is already answered...
1] County boundary data is provided by a 3rd party (PGC, or where PGC gets its county data) and explicitly allowed;
2] DeLorme boundary data, for one, isn't allowed;
3] Altitude challenges are allowed, and that data is also pulled from a 3rd party data source.
So, if altitude is allowed as a challenge metric, but DeLorme polygons aren't, yet both are pulled from 3rd party data sources, why isn't DeLorme (or other 3rd party data sources) allowed?  My interpretation of the guideline limitations is that altitude is not a region-based polygon like DeLorme is, and so is a different concern, and Groundspeak chose to allow altitude for challenges.  For lat/lon based regional polygon boundaries however, only Counties are allowed.  And as far as I know, that's worldwide, without exception.

Perhaps the thread title is a little off center.  Authoritative third-party data sources are allowed (explicit allowance for counties and altitude).  Obviously the gist of the request is: Allow challenge caches based on authoritative third-party regional/polygonal data sources (DeLorme, et al).  But altitude allowance isn't justification for allowing them since that's not region/polygon-based.

Ok head spinning, it's late, bed time.

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1 hour ago, thebruce0 said:

Obviously the gist of the request is: Allow challenge caches based on authoritative third-party regional/polygonal data sources (DeLorme, et al).

Yeah, the subject line could be clarified. But the initial post shows that my concern is with the location-based criteria (e.g., DeLorme, USGS) that are currently prohibited.

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1 hour ago, niraD said:

Yeah, the subject line could be clarified. But the initial post shows that my concern is with the location-based criteria (e.g., DeLorme, USGS) that are currently prohibited.

You also noted that you have not tried to publish any. Maybe you can find a way to map coordinates to DeLorme or USGS without using polygons or patterns.;)

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20 hours ago, thebruce0 said:

As a specific example, I'd hoped to publish a challenge where you form a pattern on the DT grid over a certain threshold. Calculable, and even had a checker programmed to verify qualification. But it wasn't allowed essentially because a CO could create any number of arbitrary patterns, and patterns aren't allowed.

That's understandable to me.  Pick any three waypoints and one can create a polygon.  Someone else can create a different polygon even if one of the waypoints has a single digit difference in the least significant digit of the lat or long value.  Although, due to the precision of the coordinate format, there isn't an infinite number of potential polygons (and thus different challenges) that could be created.  But that's not what this thread is about. It's for a feature request to allow challenges based upon  pre-defined polygons from an authoritative source. 

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Hmm.

I now understand why Groundspeak doesn't want to allow "draw your own map" as a CO who really wants the challenge to be "Find these 5 specific caches" could draw a map with only those 5 in them.

I still don't really see the problem with "Caches based on authoritative third-party data sources".   Doesn't matter if is Delorme or some other brand of map.. if it is a map and a checker can check.

Possibly the issue is what is "authoritative".     Arguing with myself here, I could make a map with just these 5 caches I want, host it publically, and claim it is a "third party source".

I still feel if Groundspeak understood how popular these are, and that 99% of them are in the spirit of what they would like.. they are location based and not arbitrary.. that some solution could be found.    

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3 hours ago, redsox_mark said:

Possibly the issue is what is "authoritative".     Arguing with myself here, I could make a map with just these 5 caches I want, host it publically, and claim it is a "third party source".

Agreed - I think GS may think that if it's opened to others then people will want to claim "But this is an authoritative source!" and they'll have more appeals on their hands.  Reviewers won't want to deal with having to decide which 3rd party sources are acceptable. So, only Counties are allowed per the guidelines.

Basically the guidelines are a whitelist. It may be that in time they could whitelist DeLorme, but that may still invite more criticism - why DeLorme and not this or that other source?  Counties are a generic government-authored regional data set; essentially worldwide. No 3rd party organization.  I suppose various resources for accurate county boundary data may have slightly different values, or be slightly incorrect or out of date after changes, but ultimately that's for PGC to decide from which source it retrieves its polygon data; which resource is most accurate (and/or adjust them themselves? *shrug* In which case PGC would be the 3rd party data source =P)

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5 minutes ago, thebruce0 said:

Agreed - I think GS may think that if it's opened to others then people will want to claim "But this is an authoritative source!" and they'll have more appeals on their hands.  Reviewers won't want to deal with having to decide which 3rd party sources are acceptable. So, only Counties are allowed per the guidelines.

Basically the guidelines are a whitelist. It may be that in time they could whitelist DeLorme, but that may still invite more criticism - why DeLorme and not this or that other source?  Counties are a generic government-authored regional data set; essentially worldwide. No 3rd party organization.  I suppose various resources for accurate county boundary data may have slightly different values, or be slightly incorrect or out of date after changes, but ultimately that's for PGC to decide from which source it retrieves its polygon data; which resource is most accurate (and/or adjust them themselves? *shrug* In which case PGC would be the 3rd party data source =P)

I understand.

In the UK, actually "counties" is not definitive.    Local government here is complicated.. we have counties with towns inside, we have cities which are not in a county, and we have something called "unitary authorities".    I've seen debates on some challenges about what should count as a county (no pun intended).    I won't bother everyone with the details, but the two sources I use (Project-GC and GSAK) have very different views of what is a "county".    For new challenges at least, as they need a checker, by definition Project-GC own the definitive map.   

But I expect this is a minority case, and that in most countries there is clarity about what a "county" is (though it may be called something different of course).

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I sympathize :) Yeah PGC would have to decide on what data source to use for Groundspeak's "County" class of data.  That might be an argument for having PGC use some other "3rd party data source" if County data doesn't already exist :)

Edited by thebruce0

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6 hours ago, redsox_mark said:

I still feel if Groundspeak understood how popular these are, and that 99% of them are in the spirit of what they would like.. they are location based and not arbitrary.. that some solution could be found.   

I don't think there's any question GS understood how popular DeLorme challenges are. In fact, someone would have to think GS was was really out of touch not to know something so obvious. So I think you need to adjust your thinking about why GS did what they did. In other words, consider that GS doesn't seem to care how popular DeLorme challenges are.

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10 minutes ago, dprovan said:

So I think you need to adjust your thinking about why GS did what they did. In other words, consider that GS doesn't seem to care how popular DeLorme challenges are.

Or, they've weighed the merit of allowing DeLorme against not allowing any other 3rd party data sources, and have reasoned to not allow any other 3rd party data sources (as unfair as that may seem to some, which undoubtedly they understand).

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3 hours ago, redsox_mark said:

I understand.

In the UK, actually "counties" is not definitive.    Local government here is complicated.. we have counties with towns inside, we have cities which are not in a county, and we have something called "unitary authorities".    I've seen debates on some challenges about what should count as a county (no pun intended).    I won't bother everyone with the details, but the two sources I use (Project-GC and GSAK) have very different views of what is a "county".    For new challenges at least, as they need a checker, by definition Project-GC own the definitive map.   

But I expect this is a minority case, and that in most countries there is clarity about what a "county" is (though it may be called something different of course).

Geonames has a hierarchy of administrative divisions (ADM1, ADM2, ADM3)  under a "Country".  An ADM1 division is basically a U.S. State or it's equivalent.  ADM2 is a second-order administrative division, and is what is used to describe a county or it's equivalent.  Geonames has pretty much become the defacto standard for identifying geographic divisions within a country, and many sites which provide polygon data typically use the geonames administration divisions rather than refer to them as States, or Counties.

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19 hours ago, NYPaddleCacher said:

Geonames has a hierarchy of administrative divisions (ADM1, ADM2, ADM3)  under a "Country".  An ADM1 division is basically a U.S. State or it's equivalent.  ADM2 is a second-order administrative division, and is what is used to describe a county or it's equivalent.  Geonames has pretty much become the defacto standard for identifying geographic divisions within a country, and many sites which provide polygon data typically use the geonames administration divisions rather than refer to them as States, or Counties.

Thanks.  That Geonames site is interesting.   For the UK, the ADM2 list looks like what Project-GC uses.     For "States" of course no polygons are needed as that data is on the cache page.   

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