[Xastir] Tiger 2007 shapefile issue...a beaut

[Gerry Creager]

Richard Polivka, N6NKO wrote:
> Gerry,
> 
> Yes, the coffee has kicked in and I had egg-on-face for breakfast. The 
> map in QGIS looks just like the same as the aforementioned area when at 
> full extent view. Zoomed in, it works.

The egg comment has to do with a Census screwup... It's Census, it's 
gonna happen.  Their view of GIS has been "interesting" for some time.

I am glad you got it to work!

> Error budget - Well, I am within 5 ft on backtracked trails. Can't 
> complain for working under a tree canopy.

1.8m isn't bad, at all!  Now: Imagine what happens when your typical 
error is 2-3 meters, and a picnic table is smaller in at least one 
dimension is smaller than the error budget.  The geometry is, well, 
interesting, and usually looks more like a bow-tie than a rectangle. 
Getting several points to define the radius of a trash can gets even 
more entertaining.

> I had the GPS unit on top of a 7 ft PVC pipe talking to my smartphone 
> over bluetooth. I just ran out of time to cover the whole place but the 
> proof of concept pans out.

When I go do this stuff, I use a 2m "range" pole.  a fixed height 
fiberglas and metal deal designed to poke holes in shoes and give one a 
good feel that their antenna is exactly this high above the point in 
question.  We also have a bulls-eye level on it to allow us to get it 
spot-on above the point in question.

Your rig sounds easier to work with.

gerry

> Now its off to other work tasks.
> 
> 73 from 807,
> 
> Richard, N6NKO
> 
> 
> Gerry Creager wrote:
>> Richard Polivka, N6NKO wrote:
>>> Gerry,
>>>
>>> Good morning!
>>>
>>> I realize that wholeheartedly, but to have this big of a 
>>> screwup....oh, wait, this is the Federal Government....
>>
>> Aha!  Your coffee kicked in?  What hardware are you using for your 
>> campground survey?  I can tell you stories about those from several 
>> years ago, when folks were trying to resolve objects (e.g., a picnic 
>> table) that was smaller than their uncorrected L1 error budget...
>>
>> gerry
>>
>>> Gerry Creager wrote:
>>>> Richard Polivka, N6NKO wrote:
>>>>> I admit that one point does not make a trend but what I found was 
>>>>> eyeopening.
>>>>>
>>>>> I wanted just Fond du Lac county in Wisconsin to use as a base map 
>>>>> for mapping project that I am working on ( a Boy Scout campground). 
>>>>> I pulled in my files into QGIS and then brought in  
>>>>> "fe_2007_55039_edges". I did not get Fond du Lac County but a huge 
>>>>> overview of north Illinois, Indiana and SE Michigan. OUCH!!!
>>>>>
>>>>> I even went and downloaded a virgin fileset and got the same 
>>>>> results (see picture).
>>>>>
>>>>> 55039.png
>>>>> This is not good. I plan on sending on a comment to the Census Bureau.
>>>>>
>>>>> So, let the user beware - YMMV.
>>>>
>>>> Unfortunately, this warning has always been necessary with TIGER 
>>>> files.  They're not the best GIS data source.  They're just 
>>>> available and free.
>>> _______________________________________________
>>> Xastir mailing list
>>> Xastir at xastir.org
>>> http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir
>>
> _______________________________________________
> Xastir mailing list
> Xastir at xastir.org
> http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir

-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843