Now clip your raster based on the shapefile:
1. From the Spatial Analyst dropdown menu select Options
from the General tab and specify Analysis Mask = Shapefile.
2. Click on the Extent tab and specify Analysis Extent = Shapefile.
3. From the Spatial Analyst dropdown menu select Raster Calculator.
4. Double-click your raster listed under Layers so it appears
in the expression box.
5. Click on the Evaluate button.
A new raster will appear in the table of contents with the
same extent as the shapefile. You may need to turn off the
other layers to see the new raster.
You can also do this procedure with an existing shapefile.
Instead of going through the above steps to create a new shapefile,
simply use the existing shapefile in the "Now clip your
raster based on the shapefile" steps.
ArcCatalog
Q:
How do I define the projection of a coverage in ArcCatalog?
A:
You need to:
1. Open ArcCatalog and browse to the coverage that you
need to define a projection for.
2. Right-click on the coverage and select Properties.
3. Click on the Projection tab then click on the Define
button.
4. You are now presented with two options; to define the
coordinate system interactively or to define the coordinate
system to match that of an existing data set that has a
projection correctly set. Select the method you wish to
use and click Next.
5. If you select to match your coverage's coordinate system
to that of another coverage, you are prompted to browse
to the coverage you wish to use to select it, then click
Next and Finish.
6. If you select to define the coordinate system interactively,
you will need to know what projection you wish to define
for the data. The first step is to select the projection
you wish to use from the list of Projections and click Next.
7. Once you have selected the projection, you will need
to define the various parameters which are unique to each
individual projection.
8. Once the projection and parameters are set, the Datum
and Spheroid will also have to be defined (for some projections
this option will be greyed out).
9. Click on Finish and the coverage now has a projection
defined.
ArcToolbox
Q:
How do I convert my raster data to a Mr.SID format?
A:
This can be done in ArcCatalog or ArcToolbox.
All ArcGIS users can encode individual rasters up to 50 MB.
An additional MrSID Encoder license is required to compress
and mosaic multiple images up to 500 MB in total size.
Steps to do this in ArcCatalog:
1. Open ArcCatalog.
2. Browse to your Raster and select it.
3. Right Click the mouse.
4. Then select "Export=>Raster to MrSID".
Steps in ArcToolbox:
1. Open ArcToolbox
2. Select "Conversion Tools=>Export from Raster=>Raster
to MrSID".
Q:
What is the difference between the Define Projection
Wizard tools and the Project Wizard tools found in the Projections
Toolset in ArcToolbox?
A:
In ArcToolbox, located in the Data
Management tools are a collection of Projection Tools. These
tools define a geodataset's coordinate system information
if it is missing, modify a geodataset's existing coordinate
system information, and convert a geodataset from one coordinate
system into a different coordinate system.
In order to reproject a geodataset, the geodataset must have
a projection defined. You can use ArcToolbox to define a geodataset's
projection.
The Define Projection Wizard tool and Desktop Define Projection
Wizard tool are used to define a geodataset's coordinate system
information if it is missing, or modify a geodataset's existing
coordinate system information. The Define Projection Wizard
tool is used for coverages, grids, and TINs. The Desktop Define
Projection Wizard tool is used for shapefiles and geodatabase
(feature classes and feature datasets).
The Desktop Project Wizard tool and Project Wizard tool are
used to convert a geodataset from one coordinate system into
a different coordinate system. The Desktop Project Wizard
tool is used for shapefiles and geodatabase (feature classes
and feature datasets). The Project Wizard tool is used for
coverages and grids.