topic Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference in .NET Maps SDK Questions

Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Mon, 16 Apr 2018 18:57:14 GMT

I am opening a shapefile that was exported from another commercial software package and the spatial reference has a Wkid of 0. It looks like the spatial reference wasn't identified by the SDK even though I can see in the .PRJ file that it is a publicly defined projection system. The spatial reference appears to work except that shapefile tables can't be reprojected and I need it to be visible when I am showing other data in the publicly defined projection system. I am using ArcGIS Runtime SDK for .NET 10.2.7. Any help with this would be appreciated.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

MelitaKennedy — Mon, 16 Apr 2018 20:24:50 GMT

Can you post the contents of the prj file? Or give its well-known / Authority ID? If you don't want to post it it publicly, send it to mkennedy at esri dot com.

Melita

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 12:23:30 GMT

PROJCS["NAD_1927_StatePlane_Texas_South_FIPS_4205",GEOGCS["GCS_North_American_1927",DATUM["D_North_American_1927",SPHEROID["Clarke_1866",6378206.400,294.97869821]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",2000000.000],PARAMETER["False_Northing",0.000],PARAMETER["Central_Meridian",-98.50000000000000],PARAMETER["Latitude_Of_Origin",25.66666666666666],PARAMETER["Standard_Parallel_1",27.83333333333333],PARAMETER["Standard_Parallel_2",26.16666666666666],UNIT["Foot_US",0.30480060960122]]

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 12:28:01 GMT

And the shapefile came from Petra by the way. My understanding was that it was created using Petra's definition for NAD 27 Texas South. Again the map control seems to be able to display the culture data but the spatial reference is failing to find the Wkid as far as I can tell. If there is something non-standard about this, do you know of a solution for verifying that I can do prior to import? Is there any way to clean it up or translate prior to import perhaps. I have to be able to work with this kind of data or look for another tool.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 17:22:40 GMT

If there's no known matching SRID it will be 0. What is the WkText property returning?

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

MelitaKennedy — Tue, 17 Apr 2018 17:47:53 GMT

Morten Nielsen‌

Morten,

Rob checked the WKT in the projection engine, and it was able to find the WKID. The only difference I see is that the standard parallel 1 and 2 values are swapped. In the projeng, we internally swap them because our convention is lower/smaller value is in SP1, but EPSG and some others use a north-to-south convention. WKID is 32041.

EDIT: Fixed the WKID number.

Melita

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 17:50:29 GMT

The same as what's in the PRJ file that I supplied above. How does ArcGIS lookup the SRID? Is it on the SR name? Wkt perfect match? There is some kind of lookup being done there. When I look at spatialreference.org it appears that this SR has been renamed. The old ESRI documentation shows the name that is in the Wkt that I supplied above but looking that same ID(32041) up on spatialreference.org the name shows as NAD 27 / Texas South. Obviously that would fail a name lookup.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 17:56:49 GMT

We'll look into why the corresponding SRID isn't being identified, but if the WkText property returns the projection string, it should work just fine for you. Are you seeing any issue with drawing the data in the correct location?

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

MelitaKennedy — Tue, 17 Apr 2018 18:06:09 GMT

If the Esri projection engine is being used, it does an exhaustive check. Names must match (although there's some flexibility with underscores, white space, alias) and values must match. The name you have matches the Esri name, not the EPSG name (see http://www.epsg-registry.org).

http://spatialreference.org has a superset of EPSG, Esri, plus whatever other information someone can find for a particular coordinate reference system, including plenty of duplicates as individuals add entries.The "ESRI WKT" string in the 32041 entry is in the Esri style, but the name is the EPSG name.

The EPSG Geodetic Parameter Registry (disclosure: I'm on the subcommitte that maintains it) and Esri both curate additions and changes to our sets of coordinate reference systems and transformations.

Melita

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 18:07:37 GMT

This basic sample seem to work just fine with 100.2.1 so it might be shapefile specific

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 18:13:13 GMT

Oh I just realized you're still using 10.2.7, and the simple example above does reproduce the behavior you're seeing with that version.

Anyway you should be OK, as the projection is understood. If you really need the ID, I'd encourage you to consider migrating to v100.x as this is where you'll see a lot of bug fixes and new innovation (10.2.7 is already in extended support which ends in November).

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 18:19:24 GMT

...also if you update the .prj file to contain this instead, it seems to work ok:

PROJCS[\"NAD_1927_StatePlane_Texas_South_FIPS_4205\",GEOGCS[\"GCS_North_American_1927\",DATUM[\"D_North_American_1927\",SPHEROID[\"Clarke_1866\",6378206.400,294.97869821]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Lambert_Conformal_Conic\"],PARAMETER[\"False_Easting\",2000000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",-98.5],PARAMETER[\"Standard_Parallel_1\",26.16666666666667],PARAMETER[\"Standard_Parallel_2\",27.83333333333333],PARAMETER[\"Latitude_Of_Origin\",25.66666666666667],UNIT[\"Foot_US\",0.3048006096012192]]

The only difference seems to be at the very ends of the last few digits. Melita can probably confirm that the comparison has been improved since 10.2.7 to handle small rounding differences, but that seems to be what is happening.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 19:05:36 GMT

Actually that should be 32041 which is Texas South. 32040 is Texas South Central from FIPS 4204. But these are well known systems that are failing lookup. Any ideas what I can do about it this in my application? Is there a way to convert these at all?

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 19:12:52 GMT

We would have switched to v100 early last year but it just started supporting WMS in December. Now we are a year into this project and have to deliver soon. Migrating will take months and will be a hard sell even after this release is delivered.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 19:16:43 GMT

The file is displayed on the map by itself just fine. The problem is that I was told that Shapefiles cannot be reprojected into another projection system. So if I have other data in the correct projection system(32041) and this is a kind of custom projection system by Wkt with Wkid-0 then it can't reproject and be in my map that's in 32041.

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 19:19:51 GMT

So has the name change by EPSG then broken compatibility with older tools like Petra?

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

dotMorten_esri — Tue, 17 Apr 2018 19:20:27 GMT

Aaah yes that's a good point. I believe 10.2.7 didn't reproject shape files (v100.x does).

I don't really have any other ideas than try and update the .prj files to something that works. The "correct" string is easy to get with 'new SpatialReference(32041).WkText`

Re: Shapefile opens with SpatialReference Wkid-0 for well known SpatialReference

DavidMillican — Tue, 17 Apr 2018 19:30:10 GMT

Ok. Thanks to both of you for your help on this. I have a better understanding of the problem now. It sounds like if I want something for now to work with 10.2.7 that I'll have to create some kind of conversion table mapping the same Wkid to multiple names. If you guys had a REST service that did this it would be great. The fact that v100 reprojects shapefiles will help me sell management on the upgrade so thanks for revealing that as well. Thanks again for all of the information.

-David