A conversation with the Google Earth API


Dustin: Oh hey there, Google Earth, it looks like you have an API so that we can actually talk to each other.
GE: Yeah, hello! It’s really useful.
Dustin: Well, we’ll see about that. So, I’ve turned you on. Can you tell me what layers you have?
GE: Of course! I’ve got the Geographic Web, Roads, 3D Buildings, Street View.. [goes on a long list]
Dustin: Oh that’s great. So, can you tell me what is in each layer?
GE: …
Dustin: Hello?
GE: …
Dustin: Oh. I see. Well if I zoom in, I can see that panoramas from Street View are now rendered as spheres floating in space where the picture was taken. That’s really cool! But, I guess you can’t tell me where they are. I’m looking at a few now. Which ones are they?
GE: …
Dustin: Okay. What about this one? 482 Avenue of the Americas in NY, NY.
GE: Oh yes. I’ve memorized that one now.
Dustin: Okay. What do you see now?
GE: 482 Avenue of the Americas in NY, NY. That’s all.
Dustin: Oh. Well, can you memorize that street view locations for 478, 486, 490 too?
GE: Yep! Done.
Dustin: Okay, what do you see?
GE: 478, 482, 486, 490 Avenue of the Americas in NY, NY.
Dustin: So you’ll only tell me you see something if I specifically tell you to look for it?
GE: Yes.
Dustin: Well what about that panorama over there? 94 W 12th Street?
GE: Sorry I don’t know what you’re talking about.
Dustin: Really. Memorize 94 W 12th Street.
GE: Ah, yes. So now I see 478, 482, 486, 490 Avenue of the Americas and 94 W 12th Street in NY, NY.
Dustin: Okay fine, you’re young so it’s okay. Now, can you tell me in latitude and longitude where 482 Avenue of the Americas is?
GE: …
Dustin: No? But its right there on the screen. I can click on it to make you fly to it!
GE: Oh, I can fly there!
Dustin: Where is 482 Avenue of the Americas?
GE: …
Dustin: I said where is 482 Avenue of the Americas?
GE: …
Dustin: Please fly to 482 Avenue of the Americas.
GE: Done.
Dustin: Okay, where are you now?
GE: [gives a series of latitude and longitude coordinates of where it’s looking]
Dustin: I see. So, you can’t tell me where 482 Avenue of the Americas is, but I can ask you to fly right to it and then you’ll tell me where you are. It seems like you’re trying to make my life difficult.
GE: [shrug]
Dustin: Okay, now that I’m sitting at 482 Avenue of the Americas and looking towards the horizon like I’m driving. Cool! So, let’s turn to the left to look over there.
GE: [turns slightly to the left]
Dustin: Wait, hold on, I’m not in the sphere anymore. I’ve moved over to the right of the road somehow.
GE: Yes, I turned you around the Focus point!
Dustin: What? What is that?
GE: It’s where you’re looking at.
Dustin: I thought I was looking at the panorama at 482 Avenue of the Americas.
GE: Actually, that’s what you told me to do, but I decided to fake it by making you look at a point 60 meters to the north at a really shallow angle. You weren’t actually looking at the panorama at all.
Dustin: Can I look directly at the panorama at all?
GE: …
Dustin: …
GE: When I look at something, its defined by the point on the earth itself, and then the compass angle, vertical tilt, and distance I am from it. The panorama is just floating above the Earth, so you can never truly look at it.
Dustin: But there’s little controls I have on you that let me move you around whatever way I want. However, when I actually want to talk to you I can only tell you to move in certain ways.
GE: Yes.
Dustin: Well okay. Let me think. I know! How about, instead of looking at a point 60 meters to the north of the panorama, I tell you to look at a point 60 meters to the northwest, and then make the compass angle so that the panorama is in the center of your view.
GE: Like this?
Dustin: Wow! It’s like I rotated 45 degrees around the panorama.
GE: No it isn’t. Not exactly. That’s not what I did.
Dustin: Shut up, it looks like I did, and that’s all that matters.
GE: Okay.
Dustin: So, in order to rotate around a panorama as if I’m viewing it, I need to exactly tell you the panorama I want (I can’t ask which panoramas are available). Then, I have to tell you to fly to it. Then, I have to ask you where I am, and the answer you give back to me is some point 60 meters away from the panorama. Then, I have to do some clever trigonometry to figure out where on earth the actual panorama is. Then, in order to rotate around the panorama to look at it from different angles I have to make up different points on the Earth in latitude and longitude which are on the opposite side of the panorama I want to look at. Then I can tell you to fly to those points, which don’t explicitly look at the panorama but panorama happens to exactly be in the way of the point on the ground I told you to look at.
GE: …
Dustin: Right, you’re not much help here are you?

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