Thanks Thor, Thanks for the prompt reply. I understand the difficulty with having different suppliers of elevation data and you are correct in saying that the resolution is much more important than the source. Therefore I think your solution of possibly providing resolution information with the elevation responses is an excellent idea.
In the meantime people can use my site to compare the Google data with SRTM3 in their geographic area of interest. Best regards, Steve. On May 26, 2:39 am, "Thor (Google Employee)" <[email protected]> wrote: > Just FYI, It's not that we do not want to say what the source is. It's > just that, as with much of our geo data, we obtain data from many > different providers (over 100 for elevation alone) which we stitch > together to provide the best possible level of coverage. So we would > have to provide source information per request, which is a lot of > engineering for little gain. > > The main reason most developers are asking for source information > appears to be because they want to know the resolution. This being the > case we are looking into providing resolution information in Elevation > responses in future. > > Many thanks, > > Thor. > > On May 25, 9:18 pm, SteveYoungGoogle <[email protected]> > wrote: > > > The new elevation data is a fine feature but for some reason that I > > don't understand no one seems to want to say what the source of the > > data is or what the resolution of the data is. See my own unanswered > > post > > herehttp://groups.google.com/group/google-maps-js-api-v3/browse_thread/th... > > and the same unanswered question from ibgpsn > > herehttp://groups.google.com/group/google-maps-js-api-v3/browse_thread/th... > > > I have written a short script that compares the two datasets which can > > be accessed > > herehttp://members.chello.at/stephen.joung/indexGoogleHeights_v3_2.html > > > You can enter coordinates or simply click on the map to set two ends > > of a profile. The elevation of these two markers is then given using > > the Google elevation data and the SRTM3 elevation data and a profile > > is shown indicating the heights between these two markers from both > > the Google ldata and the SRTM3 data. The profile data is called every > > 100m from the start marker for both datasets. > > > The SRTM3 data offers a resolution of 3arc-seconds (about 90m) and I > > hope this comparison site will be useful to anyone that needs to check > > the accuracy of the Google Elevation Data. It would still be nice for > > us to be told the source and resolution of the Google Elevation Data. > > > BTW, SRTM3 shows sea level as 0m but Google data includes undersea > > elevations. > > > -- > > You received this message because you are subscribed to the Google Groups > > "Google Maps JavaScript API v3" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group > > athttp://groups.google.com/group/google-maps-js-api-v3?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-maps-js-api-v3?hl=en.
