On 04/27/2011 08:51 PM, Chuck Young wrote:
I am new to this list and hope you can help.
I have a GeoTif raster file that currently shows "+proj=longlat
+ellps=WGS84 +datum=WGS84 +no_defs" as its CRS in the Options form
in QGIS.
I have the Tiger shapefile that has in
the .prj file
GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
I have added several vector layers that I have created with QGIS
and all have the following in their .prj files.
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
I need to be able to get the Tiger data to align with the GeoTif
and other layers.
Assuming your *.prj files are correct, you should be able to enable
"on-the-fly" projection and the Tiger shapefiles should fall in the
correct place.
You need to:
* first load the GeoTiff,
* open the project properties, and be sure the CRS is set the same
as the GeoTiff (EPSG 4326 based on what you posted above)
* in the same project properties window, check the "Enable
on-the-fly" checkbox.
* Now load the tiger shapefiles.
That should do it.
I tried to export the
Tiger file using the Vector / Data Management Tools / Export to
new Projection
I first loaded two Vector layers. First a local layer that was
in the desired projection. (a layer that I created ) having the
same info in the .prj file as noted above [WGS 1984].
Then I loaded the tiget shapefile layer.
I selected the Import spacial ref from existing layer
I tried switching the input and output selections both ways:
first I selecting local layers spacial ref system
"+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" as Input
and the Tiger shapefile spacial ref "+proj=longlat
+ellps=GRS80 +datum=NAD83 +no_defs" as output
This created a set of files
Then I switched the input and output
Both produced the following in the .prj files
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
I load any of these with the rest of
the layers and zoom extents and get a white screen with a little
speck in one corner. That speck is the raster layer and all the
layers I created manually.
I found some more info in the meta data of the different
files I was asking about.
For the locally created vector layer the mete data shows:
|
Storage type of this layer: ESRI
Shapefile
|
|
Source for this layer: D:/Program
Files/Quantum GIS Copiapo/Rural Roads.shp
|
|
Geometry type of the features in this
layer: Line
|
|
The number of features in this layer: 4
|
|
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 460941.66,3797094.89 : xMax,yMax
489349.06,3809257.00
|
|
Layer Spatial Reference System:
|
|
+proj=longlat +ellps=WGS84 +datum=WGS84
+no_defs
|
And for the Tiger file it shows:
|
Storage type of this layer: ESRI
Shapefile
|
|
Source for this layer:
J:/FileTransfer/AerialPhotoGila/LandSat/GIS Data
Tiger/tl_2010_04007_roads/tl_2010_04007_roads.shp
|
|
Geometry type of the features in this
layer: Line
|
|
The number of features in this layer:
14807
|
|
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 -111.721,32.985 : xMax,yMax
-110.001,34.4434
|
|
Layer Spatial Reference System:
|
|
+proj=longlat +ellps=GRS80 +datum=NAD83
+no_defs
|
Maybe this will help in your answer.
Please help!
Thanks
Chuck
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