NSW Bushwalking Mapping Group

[Allchin09]

Hello!

In 2016 I meet up with a few bushwalking friends and formed a "NSW Bushwalkers Mapping Group", essentially a group with a mission of being the 'go to' point of reference for all bushwalkers mapping desires in NSW.

We haven't been overly active since, but it's something I'd like to put more time into this year, and it would be great to have more people who are interested in maps and / or have technical skills involved.

Last year we were invited to Spatial Services out at Bathurst (the organisation responsible for mapping in the state - a branch of the old LPI or Department of Lands) to discuss how we could work with them to improve things such as track data. It was good to form some relationships here and they seem willing to work with the community where possible.

Some of our work so far can be found here - http://maps.ozultimate.com/wiki/

With so many resources available these days, one thing I'd like to do is make it easier for those who aren't so technical to make the most of what's out there.

Let me know if you want to get involved! Project ideas are also welcome.

[tom_brennan]

I thought I'd just use this thread for mapping questions.

Just in case anyone in here is a bit of an expert with ArcGIS Server, I've been trying to use the public NSW POI database:
http://maps.six.nsw.gov.au/arcgis/rest/ ... /MapServer

If I query a particular point of interest (MOUNT CLOUDMAKER)
http://maps.six.nsw.gov.au/arcgis/rest/ ... er/0/50740
I get the following co-ordinates:
"x": 16718087.184249997,
"y": -4021518.6212499999

Does anyone know what system this is in? According to the layer details:
http://maps.six.nsw.gov.au/arcgis/rest/ ... apServer/0
it's supposed to return data in GDA94 (http://spatialreference.org/ref/epsg/4283/) but it's clearly something else. I can't for the life of me work out what.

Extent:
XMin: 140.99940164475152
YMin: -37.50381101781631
XMax: 159.25057410697562
YMax: -28.124891634265435
Spatial Reference: 4283 (4283)

[Allchin09]

Could it be that the coordinates for the extent are in GDA94 however the POI coordinates are in another system other than GDA94?

[michael_p]

The Cloudmaker co-ordinates appear to be in EPSG3857 format.

I have to go out now and wont be back till later. I'll write up how I arrived at this when I get home.

Michael.

[tom_brennan]

Excellent, thanks.

I plugged the x/y co-ordinates into https://mygeodata.cloud/cs2cs/ using input projection as EPSG3857 (Web Mercator) and output projection as EPSG4326 (WGS84) and it returned 150.181132389;-33.945740466 - which seems right. I also used output projection EPSG4283 (GDA94) and it was essentially identical.

Odd that the extent is in geographic co-ordinates but the output is in projected co-ordinates.

[michael_p]

EDIT: I didn't see your above reply till after I posted the info below.

Tom,

The short version.

http://maps.six.nsw.gov.au/arcgis/rest/ ... er/0/50740

If you go to the above link and click on the JSON link (under the breadcrumb) you get this:

Code:

{
 "feature": {
  "attributes": {
   "objectid": 50740,
   "topoid": 511836588,
   "poigroup": "Landform",
   "poitype": "Mountain/Hill/Peak",
   "poiname": "MOUNT CLOUDMAKER",
   "poilabel": "MOUNT CLOUDMAKER",
   "poilabeltype": "NAMED",
   "poialtlabel": null
  },
  "geometry": {
   "x": 16718087.184249997,
   "y": -4021518.6212499999
  }
 }
}

The x,y values are labelled as "geometry" not co-ordinates (clue number 1. ). After some searching I was able to workout that the x,y values are a "esriGeometryPoint". This was confirmed by the geometry type definition here: http://maps.six.nsw.gov.au/arcgis/rest/ ... apServer/0

(Reference the image below.) Using the co-ordinate tool on the https://maps.six.nsw.gov.au/ website. I selected "Other" for the co-ordinate system and entered the x,y values manually and it jumped to the correct spot on the map for Cloudmaker. From this I was able to confirm that the co-ordinate system was EPSG3857.

To convert EPSG3857 to WGS84(EPSG4326) go to this website: https://mygeodata.cloud/cs2cs/ . I put in the x,y value and converted it to WGS84(EPSG4326) and it gave: -33.945740466,150.181132389 as the lat/long. Confirmed here: https://goo.gl/maps/w8CMCJs6EZk . The https://mygeodata.cloud/cs2cs/ accepts a list of value pairs so you could collect points in a csv to do a bulk convert.

Hope this helps.

Cheers,
Michael.

Last edited by michael_p on Thu 30 Mar, 2017 9:53 pm, edited 1 time in total.

[michael_p]

Excellent, thanks.

You're welcome. I enjoyed the exercise.

Odd that the extent is in geographic co-ordinates but the output is in projected co-ordinates.

Yes, it makes no sense to me why it would be done this way.

Michael.

[tom_brennan]

Finally making progress with building the query. Since it seems to have taken me too many hours, I thought I'd post it here so that others might be able to do it in less time:
http://maps.six.nsw.gov.au/arcgis/rest/ ... ue&f=pjson

If anyone knows why this won't return the geometry, even though returnGeometry=true, I'd be keen to hear.

[michael_p]

This JSON stuff is above my pay grade but I'll have a look at this later and see if I can figure it out.

To make your query easier to read I have put it in code quotes:

Code:

http://maps.six.nsw.gov.au/arcgis/rest/services/public/NSW_POI/MapServer/0/query?where=poigroup+in+%287%29+and+poiname+like+%27%25COXS%25%27&outFields=objectid%2Cpoiname&orderByFields=poiname&returnGeometry=true&f=pjson

[michael_p]

This REST API/ARCGIS/NSW SIX stuff is a bit of a rabbit hole and my head is spinning.

I am no expert in this area so I could be wrong. After doing a lot of reading over the last couple of days I have come to the conclusion that you may not be able to get the returnGeometry info when doing a "where" query.

There appears to be a limit to what data can be retrieved as a "where" query can only be run against a layer. Maybe (I repeat, maybe) the geometry data is not in the same layer (or it may be in a separate table), therefore can't be queried in conjunction with a "where" query.

I found a site with several working example queries (sorry I can't find it now, if I do I'll put a link up for it). One example had returnGeometry added to a "where" query. When I ran the example query it didn't return the geometry only the query data. Sounds familiar?

Not sure where to go from here. If I get time next week I'll go over this again and see if anything jumps out at me that I may have missed.

Michael.

[CasualNerd]

The map running on http://maps.ozultimate.com/ is very well presented, is it just NSW gov data over satellite ?

I have a few questions about NSWTopo scripts, I can't get it running here on windows 10, trying lots of different combinations of GDAL installs and now ruby isn't recognised from the OSGeo command line. Not sure where to turn, do you guys have a forum or question system ?

[michael_p]

I have a few questions about NSWTopo scripts.

You might want to have a look at this thread: viewtopic.php?f=36&t=9028

Michael.

[CasualNerd]

I have a few questions about NSWTopo scripts.

You might want to have a look at this thread: viewtopic.php?f=36&t=9028

Michael.

Thanks, tried adding ruby to PATH, but no difference, lots of useful info in that thread but I imagine I'm missing something very simple. I'll try again tomorrow.

[tom_brennan]

The map running on http://maps.ozultimate.com/ is very well presented, is it just NSW gov data over satellite ?

Yes, just using data available from the NSW Public Mapping Web Services. See http://maps.ozultimate.com/wiki/website_about for more info.

I have a few questions about NSWTopo scripts, I can't get it running here on windows 10, trying lots of different combinations of GDAL installs and now ruby isn't recognised from the OSGeo command line. Not sure where to turn, do you guys have a forum or question system ?

Yeah, best to ask questions on the link that michael_p mentioned, and keep it all in one place. People are fairly helpful. I have it running on W10/OSGeo, so it's doable!