GPS (GNSS) Resources - how does one access the data!

elidana commented 7 years ago

Hi GeoNet

I would like a word of advice on accessing GPS data from the GNS GPS website. I want to get GPS position data over a number of years at selected sites. But I just cannot figure out how to access it. It was very easy on the USGS website where you click on a station on a map and then can select and download data extremely easily. But on the GeoNet site is seems you need special knowledge. I tried and tried without luck and was going round in circles following links to different pages. I managed to find the map of GPS station locations, as well as Delta, Fits, GPS (GNSS) Resources, and so on. But I still cannot find where to access the data, and how to access it.

I would appreciate it very much if you could give me a little help - a step by step description of the process. One that someone who does not write computer code can understand.

Thanks

elidana commented 7 years ago

We are sorry that you were not able to access our data as easily as we hope it is. We are still in the process of developing and improving our users experience, so hopefully you will find the data access much more easy in the near future.

For now, you can download our GPS time series using FITS.

There are lots of things you can do through FITS (here some general documentation and instruction for data download )

We are aware that is not as easy as point and click on a map, but hopefully with some instructions you will be able to download what you need for your project.

Step by step procedure:

1) Select the sites you are interested to

You can do this from our Network Map , select operational sites - CGPS sites

2) Grab the network code of each site

for the majority of sites network code is LI (LINZ, dark blue triangles on the map) or CG (GeoNet, light blue triangles). There are some exceptions, so if you get an error at step 3, you can double check by clicking on the site on the map, and check the “Network” value on GeoNet DELTA:Mark page that will automatically open. Another option is to check out this page

3) Download the data

You will need to download 3 files, one for the E-W time series, one for the N-S time series, and one for the Up-Down timeseries. To download data from FITS, on a new browser, where you usually type a web addresses, you will need to write the address of the GPS data you are interested to.

This address is made of a few fields:

http://fits.geonet.org.nz/observation? Always put this in front of your web address
typeID=e this value is “e” for the E-W time series, “n” for the N-S time series, and “u” for the Up-Down time series
&siteID=HOLD this value is the site code
&networkID=CG this value is the network code

So, if you want to download data for Auckland (AUCK), you’ll need to create the following web addresses: http://fits.geonet.org.nz/observation?typeID=e&siteID=AUCK&networkID=LI http://fits.geonet.org.nz/observation?typeID=n&siteID=AUCK&networkID=LI http://fits.geonet.org.nz/observation?typeID=u&siteID=AUCK&networkID=LI

The 3 links above only differ on the value associated with “typeID” Then if you copy the first addresses in your web browser and press enter, a file named FITS-LI-AUCK-e.csv will be automatically downloaded. You can open this file with Excel or any program at your preference. You will need to do the same for the “n” and “u” files.

Another example: If you want to download data for our site in Avalon (which will have a different network code), you’ll need to write an address such as: http://fits.geonet.org.nz/observation?typeID=e&siteID=AVLN&networkID=CG http://fits.geonet.org.nz/observation?typeID=n&siteID=AVLN&networkID=CG http://fits.geonet.org.nz/observation?typeID=u&siteID=AVLN&networkID=CG

elidana commented 7 years ago

Hi Elisabetta

Thanks so much for the detailed instructions. Once you know what to do it is easy. The pages I saw seem to be written from the point of view of someone used to writing computer code, and were not understandable to me when I first looked. But your step by step instructions and the examples you gave helped me to get the hang of it. A more intuitive approach would be nicer, with buttons to click that automatically type in the code words for you behind the scenes. Also it would be easier to download north, east, and up, in one package instead of doing them separately. But I am not complaining because I am glad to be able to access the data!

GeoNet / help