Comments on: Manhattan’s daytime population: map source found! http://spatialityblog.com/2009/08/22/map-source-found/ My thoughts on GIS, data access, and all things spatial. Tue, 06 Oct 2009 18:59:40 +0000 http://wordpress.com/ hourly 1 By: Joshua Daniel Franklin http://spatialityblog.com/2009/08/22/map-source-found/#comment-17 Joshua Daniel Franklin Wed, 16 Sep 2009 16:54:55 +0000 http://spatialityblog.com/?p=68#comment-17 Hey, thanks for the legwork. The 2007 Time article graphics are online here, by the way: http://www.time.com/time/2007/america_numbers/commuting.html This is probably my all-time favorite issue. I noticed some problems with the Seattle data--for example, it shows the UW campus as empty at night. That's not even true in the summer, when various camps and conferences use the dorms. Hey, thanks for the legwork. The 2007 Time article graphics are online here, by the way:
http://www.time.com/time/2007/america_numbers/commuting.html
This is probably my all-time favorite issue.

I noticed some problems with the Seattle data–for example, it shows the UW campus as empty at night. That’s not even true in the summer, when various camps and conferences use the dorms.

]]> By: Lou klepner http://spatialityblog.com/2009/08/22/map-source-found/#comment-7 Lou klepner Wed, 26 Aug 2009 15:01:38 +0000 http://spatialityblog.com/?p=68#comment-7 Excellent sleuthing, I look forward to future installments. Excellent sleuthing, I look forward to future installments.

]]> By: Steven Romalewski http://spatialityblog.com/2009/08/22/map-source-found/#comment-6 Steven Romalewski Tue, 25 Aug 2009 21:16:29 +0000 http://spatialityblog.com/?p=68#comment-6 Good point re: spatial precision vs accuracy. We do need to know more about how the Oak Ridge data was compiled in order to evaluate it, which is one reason I wanted to write about it here. I've received some feedback already, and will post more after I hear back from the LandScan team directly. Good point re: spatial precision vs accuracy. We do need to know more about how the Oak Ridge data was compiled in order to evaluate it, which is one reason I wanted to write about it here. I’ve received some feedback already, and will post more after I hear back from the LandScan team directly.

]]> By: lichanos http://spatialityblog.com/2009/08/22/map-source-found/#comment-5 lichanos Tue, 25 Aug 2009 20:40:37 +0000 http://spatialityblog.com/?p=68#comment-5 It is a bit deceptive to talk about these maps of day/night population as though they are the same sort of information as census data. They are not. Saying they have higher resolution than census data implies greater spatial precision, but says nothing about the accuracy. The key word here is "model." Oak Ridge people have decided how to estimate the day/night populations based on census data and ancillary data, e.g., journey to work, work location, etc. data. Census data is not perfect, but it is what it says, the result of a known method of surveying resident populations. Until I could look under the hood of this model, I'd regard it as interesting, but not to be trusted very much. It is a bit deceptive to talk about these maps of day/night population as though they are the same sort of information as census data. They are not. Saying they have higher resolution than census data implies greater spatial precision, but says nothing about the accuracy.

The key word here is “model.” Oak Ridge people have decided how to estimate the day/night populations based on census data and ancillary data, e.g., journey to work, work location, etc. data. Census data is not perfect, but it is what it says, the result of a known method of surveying resident populations. Until I could look under the hood of this model, I’d regard it as interesting, but not to be trusted very much.

]]> By: New York City population by day and night | Doobybrain.com http://spatialityblog.com/2009/08/22/map-source-found/#comment-4 New York City population by day and night | Doobybrain.com Tue, 25 Aug 2009 04:44:58 +0000 http://spatialityblog.com/?p=68#comment-4 [...] Steven over at Spatiality has graciously done the research and found out that the image above is part of a larger November [...] [...] Steven over at Spatiality has graciously done the research and found out that the image above is part of a larger November [...]

]]> By: Steven Romalewski http://spatialityblog.com/2009/08/22/map-source-found/#comment-3 Steven Romalewski Tue, 25 Aug 2009 04:44:20 +0000 http://spatialityblog.com/?p=68#comment-3 Thanks for the follow up! Glad my post was helpful. Thanks for the follow up! Glad my post was helpful.

]]> By: Doobybrain http://spatialityblog.com/2009/08/22/map-source-found/#comment-2 Doobybrain Tue, 25 Aug 2009 04:35:11 +0000 http://spatialityblog.com/?p=68#comment-2 Good research here. I couldn't seem to verify the Time 2007 statement but it looks like you have and I will be updating my post with the relevant information. Thank you! Good research here. I couldn’t seem to verify the Time 2007 statement but it looks like you have and I will be updating my post with the relevant information. Thank you!

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