11
votes
Accepted
When validating geometries, what are "Nested shells"?
A Nested Shell is a polygon on top of another polygon.
Image source
- 606
11
votes
Accepted
Is srsName of "EPSG:4326" spec compliant in GML 3.1 / 3.2?
Yes, srsName="EPSG:abcd" is GML-3 compliant but only in an application context where EPSG:abcd points to a CRS definition. As of 2013, OGC best practice (documented here) is to use http URIs of the ...
- 470
10
votes
Why do single-part WKT polygon vertices require double parentheses?
It is because polygons can have multiple rings in them, the exterior and a list of interior rings or holes. To save parsers having to guess if there are holes by the number of brackets there are ...
- 75.1k
10
votes
Why do single-part WKT polygon vertices require double parentheses?
@user30184 already gave the short answer in the comments here. For a longer answer, one needs to look to the Simple Feature Access - Part 1: Common Architecture | OGC standard.
The Well-known Text (...
- 741
9
votes
How are ESRI WKT projections different from OGC WKT projections?
You've caught a lot of the differences. Esri never adopted the WKIDs for the map projection algorithms or parameter names so those are all different. We didn't agree with how carefully defined the ...
- 18.2k
8
votes
Accepted
Is GeoJSON an OGC format
No, GeoJSON is not an OGC standard:
IETF Geographic JSON Working Group
The Internet Engineering Task Force, in conjunction with the original specification authors, has formed the Geographic JSON WG ...
- 3,485
7
votes
REST API for OGC standards
As @PolyGeo suggested, I am converting my comments into an answer. The answer is split into three parts to broadly reflect the three comments I made.
Part 1
Roy Fielding's dissertation that ...
- 11.9k
7
votes
Accepted
Validity standard for GeoJSON polygons?
Polygons are not simple to handle and there are more than two worlds. I recommend to read this article "About Invalid, Valid and Clean Polygons" http://www.springer.com/%3FSGWID%3D5-102-45-...
- 52.5k
7
votes
Accepted
See WFS or WMS corresponding full http request in QGIS when a layer was added from any of these services
If you have QGIS 3.14, press F12. Otherwise install the Network logger plugin.
- 52.5k
6
votes
Accepted
How are ESRI WKT projections different from OGC WKT projections?
I don't have such a list, but going through the GDAL code will guide you:
https://svn.osgeo.org/gdal/trunk/autotest/osr/osr_esri.py
https://trac.osgeo.org/gdal/browser/trunk/gdal/ogr/ogr_srs_esri....
- 75.1k
6
votes
Accepted
Is there a common standard for how GIS information is displayed?
There is SLD (Styled Layer Descriptor), which I think is mainly used in OpenGIS environments. ArcGIS might have some support for it, but I have never pursued that option myself.
- 4,173
6
votes
Accepted
Relationship between WMS styles and layers parameters for GetMap request in WMS 1.3.0?
The WMS 1.3.0 specification says in section 7.3.3.4:
The mandatory STYLES parameter lists the style in which each layer is to be rendered. The value of the STYLES parameter is a comma-separated ...
- 1,738
6
votes
Accepted
Geometry data type Binary storage description
WKB presentation is defined in the OGC standards for Simple Feature Access https://www.ogc.org/standards/sfa. The details are in the document https://portal.ogc.org/files/?artifact_id=25355, Chapter 8....
- 52.5k
5
votes
Accepted
Is there free WFS 2.0 client?
The QGIS client plugin is a good one - I was able to access the features of WFS without issue.
ArcGIS has an interoperability connections feature that must be enabled by a user with administrator ...
5
votes
Accepted
Differences between OGC and ISO WKT/WKB specification?
If you are working with geometry types beyond the usual point/line/polygon/collection or are working with more than 2 dimensions, then yes, get the ISO spec. Otherwise, no. Also get the old OGC ...
- 19.4k
5
votes
INSPIRE, GEOSS and OGC
The Open Geospatial Consortium (OGC) exists to define interface standards such as the Web Mapping Service (WMS) standard, or Web Feature Service (WFS) standard. These are standards that define how ...
- 11.9k
5
votes
Accepted
What's the difference between coordinateDimension and spatialDimension?
dimension(): refers to the topological dimension (i.e. point/line/area)
coordinateDimension(): returns the dimension of the tuple as given (as statet in the OP)
spatialDimension(): returns the ...
- 899
4
votes
Accepted
Number of zoom levels in WMS?
There is no concept of zoom "levels" in the WMS specification, as there is for an XYZ/TMS. Rather, your WMS requests just use a bounding box which determines map scale.
- 7,818
4
votes
Accepted
Using CQL for a poor man's temporal filter on a server offering only WFS 1.1.0
Note only a GeoServer based WFS will understand a CQL filter, you can and should use an OGC Filter to achieve this effect too.
You can use one (or more) of the ECQL temporal filters for this. I would ...
- 75.1k
4
votes
Accepted
Seeking open vector format for long term GIS data storage in off-line repositories?
In my opinion, Shapefile is a good choice, but it has many limitations for historical reasons. For example, a single shapefile cannot be greater than 2GB, etc. You have to decide whether to commit to ...
- 10.3k
4
votes
Failure to Add Layer from a WFS Provider QGIS 2.18.10
It may be an issue with your network or a temporary issue with the server, it works for me.
I added http://ide.igvsb.gob.ve/geoserver/escala250000/wfs/?VERSION=1.0.0 to as the WFS url and then added ...
- 75.1k
4
votes
Accepted
How to SortBy a GetFeature WFS request by FeatureId (fid) in XML?
That is not supposed to work. SortBy is defined in the WFS 1.1.0 standard as
The SORTBY parameter is used to specify a list of property names whose
values should be used to order (upon ...
- 52.5k
4
votes
Feature Identifiers in WFS
After a bit of digging I found that gml:id is of type xml:ID:
For both attributes and simple element content, the lexical domain of these datatypes is the lexical domain of XML nonqualified names (xs:...
- 75.1k
4
votes
Feature Identifiers in WFS
Rules for gml:id come from the GML standard. This is about GML 3.2
7.2.4.5 id The attribute gml:id supports provision of a handle for the XML element representing a GML object. Its use is mandatory ...
- 52.5k
4
votes
Accepted
Limit access to WMS service after number of requests
WMS standard defines only how the service should work and it is assumed that every request will get an answer. How to limit the usage of the service is not in the scope of the standard. I agree with @...
- 52.5k
3
votes
Is there an open standard for raster information?
Good question and not one I've really given thought to before. This might be the sort of thing you're interested in:
Some searching show's that there's ISO19123:2005 - "Geographic information -- ...
- 6,591
3
votes
Accepted
Mbtile To Geopackage and vice versa
Doing such a conversion (or supporting both in the same file) was a goal of GeoPackage. It isn't just a schema change though, because of different Y order conventions - you need to use a view to ...
- 12.5k
3
votes
Is there free WFS 2.0 client?
QGIS 2.16 brings an overhaul of the WFS provider, including
WFS 1.1 and 2.0 support
Source: http://qgis.org/pl/site/forusers/visualchangelog216/index.html#id96
3
votes
Is GeoJSON an OGC format
OGC Standards are listed on the OGC Standards page.
As you will see GeoJSON is not amongst them.
- 63.8k
3
votes
Server (MapServer) does not support the gml coverage
It would help a lot to mention where to get the test suite
https://github.com/opengeospatial/ets-wcs20
and which exact test you run, and also study the test suite and try to analyze what is probably ...
- 52.5k
Only top scored, non community-wiki answers of a minimum length are eligible