Subscribe to this thread
Home - General / All posts - Crazy projection
orerockon

386 post(s)
#23-Oct-19 03:08

I've been pulling my hair out over what should be a veeeery simple drawing. The BLM in their infinite wisdom pulled the ridiculously simple shp file of their CONUS district boundaries and replaced it with a hideously gargantuan gdb that MFD 9 doesn't understand and QGIS does but just barely. Anyway I got a QGIS export but since it doesn't know what the projection is neither does MFD. Importing it as Mercator projection with the default values shifts it off to the north.

Can someone translate this to an earth based language for me?<br><br>PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",<br>GEOGCS["GCS_WGS_1984",<br>DATUM["D_WGS_1984",<br>SPHEROID["WGS_1984",<br>6378137.0,298.257223563]],<br>PRIMEM["Greenwich",0.0],<br>UNIT["Degree",0.0174532925199433]],<br>PROJECTION["Mercator_Auxiliary_Sphere"],<br>PARAMETER["False_Easting",0.0],<br>PARAMETER["False_Northing",0.0],<br>PARAMETER["Central_Meridian",0.0],<br>PARAMETER["Standard_Parallel_1",0.0],<br>PARAMETER["Auxiliary_Sphere_Type",0.0],UNIT["Meter",1.0]]<br>

Attachments:
Land Ownership Image.jpg

tjhb

8,926 post(s)
online
#23-Oct-19 05:57

What is BLM?

Is this data somewhere in the United States of America?

Graeme

942 post(s)
#23-Oct-19 07:24

USA Bureau of Land Management

tjhb

8,926 post(s)
online
#23-Oct-19 08:12

Might be.

We have no source data, no projection source, snd no source.

orerockon

386 post(s)
#23-Oct-19 16:32

OK so the above info in the .prj file doesn't help? Is there a way to BS it i.e. moving the whole thing to the north? I just want to spatial overlay onto a couple thousand points, I can probably check them against the land ownership drawing they have that instantly imports at the correct projection. Damn gummint infuriates me sometimes. This took me 30 mins or so to even locate in the nightmare spiderweb of "official" US Govt data. The only numbers that aren't essentially 0 are these 6378137.0,298.257223563. Could that be the horizontal and vertical offset? Using the tracker it looks to be roughly 21.4 km too far north.

oeaulong

231 post(s)
#23-Oct-19 17:48

Orerockon,

You really need to be more precise about your sources if you expect any direct help. Please point to the details of where you found some datasets. Given an almost direct north - south discrepancy, I would put this in the incorrect datum realm, off the top of my noodle.

(Tim: yes BLM is a department of our large Dept. of the Interior, that regulates the Public Domain lands and the system(s) that subdivide them, the Land Ordinance of 1785 - PLSS (range, township, section divisions), original colonial Metes&Bounds, Texas Spanish system etc. They seem to most often work in conjunction with the USGS (US Geological Survey) to produce The core data consumed by mapping in the US for both private and public use. As adjustments are made due to modern accuracy and & precision of instruments, they carry out the changes for public lands on the ground. sry for long winded answer, just for context)

oeaulong

231 post(s)
#23-Oct-19 18:13

It looks like you are trying to bring in the BLM Administrative Districts. This was recently published with an update from 10/10/2019. A subset of the below packaged zip. Is this correct?? If so, then I changed nothing and the information is contained correctly.

https://gis.blm.gov/EGISDownload/LayerPackages/BLM_National_Administrative_Units.zip

In here I am seeing it being brought in and overlayed with Bing Maps correctly under the Pseudo Mercator projection. Please adjust your projection to Pseudo Mercator and I believe you will see it align.

See the attached image.

Attachments:
BLMAdminUnits.png

orerockon

386 post(s)
#23-Oct-19 19:14

That is one of the coverages I found. 9 doesn't recognize it when I try to import. It wants a .gdb file and the one in the folder when I unzip it "gdb" doesn't do anything. What I posted is another of the 5 or so I have located so far. I don't know where I got the file that did import with the odd projection though, I can't find the URL in my history now. How did you get it to import?

oeaulong

231 post(s)
#23-Oct-19 19:21

Imported without a hitch. Retrace your procedures. the gdb format is a subfolder with lots of files. Perhaps just going and getting the files I referred to will be a more correct set of files for you.

Have you tried to change the imported projection to Pseudo Mercator? I did a test and changed it to Mercator with the imported parameters and saw the 21km shift shown in your first message. Web Mercator = Pseudo Mercator (Mfd9).

orerockon

386 post(s)
#23-Oct-19 19:25

That's part of what I don't get, what file did you click on? I did file import type GDB files and only the 1 file "gdb" (no extension shows up. There is 1 folder in the zip file "admu.gdb" that has what I expected to see, a bunch of files and the one "gdb" is what 9 recognizes. Also I don't see "web Mercator" as an option trying to assign a projection in 8. I looked for anything named "Mercator" and there are a few choices under cylindrical.

oeaulong

231 post(s)
#23-Oct-19 20:50

I am away from keyboard to double check myself, won't be back for another 6 hours.. when you Import a file chooser dialog box comes up. Negotiate to the appropriate folder with the name of the GDB. Make sure the file type selected from the lower right has *.gdb selected. this will filter out the files. when you get inside the named folder you should just see the gdb file show up. Click on that one to import. It really should be easy. Just try and get it imported to Mfd9. Terms are different in v.8 and I don't *think* that v.8 supported the gdb format.

oeaulong

231 post(s)
#24-Oct-19 03:19

the "gdb" file with no extensions will probably be the smallest file in the subfolder. It is the one to import. Using my above download from BLM the path is this.

C:\Users\..\BLM_National_Administrative_Units\BLM_National_Administrative_Units\admu.gdb\gdb

------------------^^^ zipfile

------------------------------------------------------------^^^ organizational folder (with metadata)

------------------------------------------------------------------------------------------------------^^^GDB subfolder with loads of indexes and format specific files (64 files). The smallest one there is "gdb" only 4 bytes big with no extension. When you are looking for the file to import this is it.

adamw


8,750 post(s)
#24-Oct-19 08:42

Exactly.

A GDB data set contains a folder, usually named xxx.gdb, and the data files are inside that folder. The file named 'gdb' is used as an entry point into the data set. I suppose we could have structured the import / link for GDB to choose a folder instead of a file, but in the end that would just look for the same file named 'gdb', not a lot gained.

When a data set contains multiple GDBs, each GDB gets its own folder.

Also:

8 does not support GDBs. It can use them through 9 via 9's ODBC driver, however.

adamw


8,750 post(s)
#24-Oct-19 08:30

Web Mercator is a different name for pseudo-Mercator. 9 uses that as the default.

The coordinate system info in the first post is a PRJ file with some HTML tags thrown in. Once the tags are removed and the bracket balance is checked, it could be used directly as a value of the FieldCoordSystem.xxx properties. (We'll add some buttons to load coordinate system info from a PRJ file to the UI, too.)

The number 6378137 is a major axis of the used ellipsoid, the number 298.25xxx is its inverse flattening. The coordinate system definition is just "please take WGS84 and use pseudo-Mercator on it, with the default center of 0 lat, 0 lon.

Dimitri


5,598 post(s)
#24-Oct-19 15:19

There are step-by-step examples for importing or linking GDB in the user manual, for example here and here. (The latter link is for importing "old" GDB format - a real mess, but highly unlikely that the BLM data is "old" GDB format). Review those and follow that procedure. Projection is assigned automatically.

There is also a dated, but still directly applicable, video showing GDB import on the Videos page.

The best way to import or to link GDB is to just use the procedures in the above links. Don't add anything else. For example, if somebody damages the GDB data by "value adding" a bogus projection file, that can mess up the data set and thus mess up the import.

orerockon

386 post(s)
#28-Oct-19 20:32

Thanks everybody for the help, I just can't reproduce this in my version of Edge (the last build). What I believe you're saying is click on the tiny file "gbd" which as I said above does nothing. I've done it 100s of times in Radian which I removed when I installed edge. I was out of the GIS work for over a year and just got a ton of work handed to me a month ago so I haven't kept it up. It looks like gdbs I imported with Radian also won't work. I wonder if updating went bad? I need to try to use pseudo-Mercator on the QGIS export next. Just out of curiosity, is it easy to to setup 9's gdb drivers in 8?

adamw


8,750 post(s)
#29-Oct-19 05:51

If there are problems working with GDB in 9, there will be problems working with GDB in 8, because 8 will use GDB through 9 (through 9's ODBC driver). So, we have to solve the issues that you see in 9 first.

Could you create a fresh portable install of the latest cutting edge build (9.0.169.9) by taking the ZIP archive for it (download the ZIP file, then make sure you unblock it by right-clicking it in Windows Explorer, selecting Properties, and checking the Unblock box at the bottom if that box appears - if you don't do this and extract right away using Windows Explorer, all extracted files will be created as blocked, this may make them fail to load later) and extracting it into a new folder, try launching the 64-bit EXE, try importing the GDB cited in this post from oeaulong, and seeing if this succeeds? It the import succeeds, good, you are seeing what others are seeing on their systems, and the problem is likely with the previous install of 9. If it does not, fine, open the log window and check if there are any complaints there - chances are, there are some, post them here. Maybe there's something in PATH that makes the wrong DLLs load, etc.

adamw


8,750 post(s)
#29-Oct-19 10:23

One more thing: for the last cutting edge build, install the latest version of the C++ runtime from Microsoft. See this post, it contains a link to the download page. Older versions of the C++ runtime contained a bug which was breaking backward compatibility between binaries (in this case, between our DLLs and the DLL for the FileGDB SDK produced by ESRI), you have to install the latest version of the C++ runtime to get the fix.

Manifold User Community Use Agreement Copyright (C) 2007-2019 Manifold Software Limited. All rights reserved.