Introduction to
Geographic Information Systems in Forest Resources |
For questions 1-2, use the Willapa Bay oyster data sets (included in gis_data_src.tar.gz).
- Oyster harvest data sets (oyster_harvest.zip) are stored as Excel
spreadsheets.
The oyster harvest data are stored in decimal degrees (datum: NAD27), but
the rest of the data are projected.
- The projected data are stored in
Projection/Coordinate System: UTM
Zone: 10 North
Datum: NAD27
Units: meters
- All data should be converted to and stored in a common projection and coordinate
system before performing any multi-theme analysis. Make sure you know what
axes Latitude and Longitude represent in terms of X and Y coordinate space.
If your haul points do not "fit" the coastline, you have a problem
with projection or axes.
- Bathymetry (P270_B30.zip), with depth below the surface measured
in meters, stored as a USGS-format DEM file.
- Ownership parcels (tl_own.zip), a polygon shapefile
- Refer to the lesson on data
importing to handle tar.gz files
Tips:
- Save the oyster harvest tables as ASCII delimited text rather than dBASE
files. This will maintain all decimal places in the data, and most critically,
in the X, Y, and lbs_hrvst fields.
- Aggregate the harvest data sets together into a single shapefile representing
all harvests before attempting any GIS analysis. It is easier to create a
single theme of oyster harvests, rather than converting each spreadsheet to
its own shapefile.
- What are the mean, minimum, maximum, and standard deviation of elevation
(in meters), per harvest type, of oyster harvests? You should only
report a single record for each harvest type. Harvest type is stored in the
hrvst_meth field within the oyster harvest data tables. (20)
Consider values both above and below the surface (elevation 0), but throw
out any harvests that have no value for elevation.
Display your statistics in tabular format. Include a short description of
the table. The table does not necessarily need to be an ArcView 3.x table,
but it must presented in tabular format rather than in a sentence.
[Hint: To get X, Y, and Z (depth) coordinates for points, use the XYZ
ArcView 3.x project.]
- Report the 10 ownership parcels with the highest total harvest values. Give
the results formatted as a table displaying the ownership identification and
the total harvest per parcel. Ownership identification is based on the gibbs_num
field in the tl_own.shp theme table. Harvest amount is stored in the
lbs_hrvst field in the oyster harvest data tables. Use all parcels
in the data set. (20)
[Hint keyword: point-in-polygon]
For questions 3-4, use the Queets River vegetation data grid, which is stored
in a zipped ArcInfo workspace (queets.zip).
The grid is also stored in UTM Zone 10 North NAD27, units meters.
- Within 1000 m of cells classified as water, what is the percentage of the
landscape that is classified as Hardwood? Beyond 1000 m of cells classified
as water, what is the percentage of the landscape that is classified as Hardwood?
Put the two values in a table. (20)
- What is the overall proportion of hardwood for the entire data set? Give
a percentage value as well as the actual area classified as hardwood. (20)
[Hint keywords: distance surface and/or buffer]
- Provide a 1-page summary of what you learned this quarter and why (or why
not) it may help you in your future. (20)
Answers
Syllabus