In ArcGIS Desktop 9.3 I have 3 features I'm trying to use to extract by mask a DEM raster layer. After I extract by mask the layers visually don't line up. When I try to do further analyses (e.g., extract to point, slope, summary stats, etc.) it is clear that my mask does not line up with my features because I get -999999 as values in further analyses.
What went wrong? and what can I do to fix it?
I'll also note that my features were originally drawn polygons that I converted to features -- could this have anything to do with the problem?
Create New layer
Manually adjust polygon length & width
Copy polygon 2x so that I have 3 identical polygons
Place polygons where they belong on map (using road features layer as guide)
Convert Graphics to features (using DEM as source data for coordinate system)
- Selected all 3 drawn polygons at once and then selected to convert graphics to features
Add new features as layer
- Agreed to the menu that popped up asking to add my converted features as a layer
Extract by Mask using new layer features as input and DEM for raster input
Properties of both Layers (I didn't manually define or adjust)
Spatial Reference: NAD_1983_StatePlane_North_Carolina_FIPS_3200_Feet linear Unit: Foot_US (0.304801) Angular Unit: Degree (0.017453292519943295) False_Easting: 2000000.002616666 False_Northing: 0 Central_Meridian: -79 Standard_Parallel_l: 34.33333333333334 Standard_Parallel_2: 36.16666666666666 Latitude_ Of_ Origin: 33.75 Datum: D_North_American_1983
Projected Coordinate System: NAD_1983_StatePlane_North_Carolina_FIPS_3200_Feet Projection: Lambert_Conformal_Conic False_Easting: 2000000.00261667 False_Northing: 0.00000000 Central_Meridian: -79.00000000 Standard_Parallel_1: 34.33333333 Standard_Parallel_2: 36.16666667 Latitude_Of_Origin: 33.75000000 Linear Unit: Foot_US Geographic Coordinate System: GCS_North_American_1983 Datum: D_North_American_1983 Prime Meridian: Greenwich Angular Unit: Degree
Overall Data Frame properties:
NAD_1983_StatePlane_North_Carolina_FIPS_3200_Feet Projection: Lambert_Conformal_Conic False_Easting: 2000000.002617 False_Northing: 0.000000 Central_Meridian: -79.000000 Standard_Parallel_1: 34.333333 Standard_Parallel_2: 36.166667 Latitude_Of_Origin: 33.750000 Linear Unit: Foot_US GCS_North_American_1983 Datum: D_North_American_1983
Picture demonstrating alignment issue (2 of 3 drawn features shown)