[Qgis-user] trouble with projections

[Lee]

Kirk,

I am by no means an expert, so take any advice I give with a grain of salt.

First, you need to determine if QGIS is setting the right CRS. If it's not,
setting the appropriate CRS may help you.

I was having issues getting QGIS to project Michigan georef correctly.
Apparently QGIS is unable to recognize a specific projection type of which
Michigan Georef is. I was given a work-around (props to Howard Yamaguchi)
which involves loading the file into uDIG (another open-source software)
and performing a reprojection in the CRS I need.

Therefore, it might be useful to import your shapefiles in uDIG. If they
project correctly there, you could perform the operation (with the correct
EPSG you want) that can be found here:
http://www.townshipgis.com/resources/problems-and-workarounds/converting-michigan-georef-to-state-plane-using-open-source-tools

Perhaps someone with a higher degree of familiarity can offer a more
elegant solution.

--
all the best,
Lee Mueller
ISA Certified Arborist
Registered Forester #46043





On Thu, Mar 15, 2012 at 1:58 PM, Kirk Wythers <kirk.wythers at gmail.com>wrote:

>
> On Mar 15, 2012, at 12:14 PM, Lee wrote:
>
> Do you know what EPSG these files are supposed to be in as obtained? I
> realize you would like to use them or reproject them to 3174, but what is
> their native EPSG or CRS name?
>
>
> I got the shape files from a colleague and am not sure. Here are the text
> descriptions from the .prj files:
>
> File 1
>
> GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
>
> File2
>
> GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
>
> File3
>
> PROJCS["WGS_1984_Web_Mercator",GEOGCS["GCS_WGS_1984_Major_Auxiliary_Sphere",DATUM["D_WGS_1984_Major_Auxiliary_Sphere",SPHEROID["WGS_1984_Major_Auxiliary_Sphere",6378137.0,0.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],UNIT["Meter",1.0]]
>
>
>
>
>
>
>
> On Thu, Mar 15, 2012 at 1:10 PM, Kirk Wythers <kirk.wythers at gmail.com>wrote:
>
>> I am having trouble with the crs of a particular project which contains 3
>> shape file layers. I have two layers with display properly relative to each
>> other, however, I am dubious that the crs is correct, since they are lat
>> long yet the scale bar is displaying meters. I have another shape file,
>> that when read into qgis, does not display properly at all.
>>
>> I have tried turning off "on the fly" projections, loading one layer,
>> then turning on "on the fly" for the other layers. I have also tried
>> manually setting the project crs with to one of the layers. I have also
>> tried manually setting the crs of each layer to EPSG 3174 (Great Lakes
>> Albers). None of these approaches seems to have any effect on the problem.
>>
>> Ideally I would like all files to be EPSG 3174 with units of degrees as
>> Lat Long. Any suggestions on how I should be approaching this? Thanks in
>> advance.
>>
>> Here is the crs metadata for each file:
>>
>> FILE 1:
>>  Storage type of this layer: ESRI Shapefile
>>  Source for this layer:
>> /Users/kirkw/Desktop/latlong/meanNH4_2002.2006CLIP.shp
>>  Geometry type of the features in this layer: Polygon
>>  The number of features in this layer: 2093
>>  Editing capabilities of this layer: Add Features, Delete Features,
>> Change Attribute Values, Add Attributes, Create Spatial Index, Fast Access
>> to Features at ID, Change Geometries
>>  Extents:
>>  In layer spatial reference system units : xMin,yMin -95.917,43.0309 :
>> xMax,yMax -83.2767,49.3746
>>  Layer Spatial Reference System:
>>  +proj=aea +lat_1=42.122774 +lat_2=49.01518 +lat_0=45.568977
>> +lon_0=-84.455955 +x_0=1000000 +y_0=1000000 +ellps=GRS80
>> +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
>>
>> FILE 2:
>>  Storage type of this layer: ESRI Shapefile
>>  Source for this layer:
>> /Users/kirkw/Desktop/disturbance/reservelands/national_parks_boundaries_BTS_2006/national_parks_boundaries_BTS_2006.shp
>>  Geometry type of the features in this layer: Polygon
>>  The number of features in this layer: 555
>>  Editing capabilities of this layer: Add Features, Delete Features,
>> Change Attribute Values, Add Attributes, Create Spatial Index, Fast Access
>> to Features at ID, Change Geometries
>>  Extents:
>>  In layer spatial reference system units : xMin,yMin -167.535,18.4641 :
>> xMax,yMax -66.1064,68.6554
>>  Layer Spatial Reference System:
>>  +proj=aea +lat_1=42.122774 +lat_2=49.01518 +lat_0=45.568977
>> +lon_0=-84.455955 +x_0=1000000 +y_0=1000000 +ellps=GRS80
>> +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
>>
>> FILE 3:
>>  Storage type of this layer: ESRI Shapefile
>>  Source for this layer:
>> /Users/kirkw/Desktop/disturbance/reservelands/Wilderness_Areas/Wilderness_Areas_12.1.11.shp
>>  Geometry type of the features in this layer: Polygon
>>  The number of features in this layer: 794
>>  Editing capabilities of this layer: Add Features, Delete Features,
>> Change Attribute Values, Add Attributes, Create Spatial Index, Fast Access
>> to Features at ID, Change Geometries
>>  Extents:
>>  In layer spatial reference system units : xMin,yMin
>> -19942895.95,2066644.91 : xMax,yMax 20012095.73,11022781.37
>>  Layer Spatial Reference System:
>>  +proj=aea +lat_1=42.122774 +lat_2=49.01518 +lat_0=45.568977
>> +lon_0=-84.455955 +x_0=1000000 +y_0=1000000 +ellps=GRS80
>> +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
>>
>>
>>
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>>
>>
>
>
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