Module 9 spatial analyst

This was a difficult one for me. I learned that spatial analyst works really well with raster data to show and analyze data sets. You can create hillshades, slopes, and wieght the importants of the data that you are looking at to calculate new information

It's an awesome tool

Module 10 Aspect

Using the spatial analyst add on, I took a DEM (Digital Elevation Model) of Haywood County and I added the aspect, or direction of the slope to the model. I simplified the slope in this case to North and south slopes to make it a little bit easier to read.

Practice Quiz 2

I could have taken out the parcel layer on the locater map, but I liked the variation in color, so I kept it. I think it would look good on a blotter.

Buffers

Buffers: Buffers can be drawn at a constant distance around every feature or at a distance that varies according to attribute values. If features are close together, their buffers may overlap. You can preserve the overlaps or remove them.

Note: When using the Dissolve ALL Function with a buffer. Buffers created with the dissolve All option form a single feature called a multi part polygon. AKA the attributes go to the standard 4 objectid, shape, distance, shape length

Overlay

OverLay: When you are interested in combining data sets that overlap, overlaying is the key. You can overlay by intersecting, which preserves the area that is common to both data sets. You can also use a union that preserves everything in both areas

Dissolve

Dissolve: A dissolve creates a new data set where features in an input table that have the same value for a specified attribute become a specified feature.
Go to: Arc Toolbox – Generalization – Dissolve – Input Features (the input layer to Dissolve) Then select the attribute you would like to aggregate

Module 6 Georeferencing and snapping

Snapping (here we are making a vector layer of trail data)
Are you still with me? Ok, so snapping is a great way to georeference. So, you have your known and unknown data, right? Using the editing tool bar click the drop down to ‘start editing’note: you can only edit one data frame so if given the choice click on the one you want to edit. Using the same drop down set your ‘snapping,’ click on what you want to snap, in our case it is roads and trails. Now you want to use the edit tool to (Task) create a new feature in this case, and here we are tracing along the lines of the trails- The goal here is to make a vector layer of trail data. You can double click when you're finished and the feature will highlight. Then you can go into the attribute table and add data.
Trace tool Will allow you to trace along a feature that is highlighted, exactly copying it
How to highlight a feature click on it with your edit tool

Module 6 Part 2 Georeferencing

Georeferencing Part 2
What kind of coordinate system, what is the map projection, what spatial reference that our data is in? Go to Arc Catalog- file folder- metadata
Or Contents – right click properties- XY Coordinate System You can check out the projection.
Now that the trail map has been georeferenced, the next step is to use it to create a vector layer of the trails complete with attribute information.
So we go to the Bent Creek Folder and Right Click New- New File Geodatabase
Then we need to create a new feature class for the database so we right click on the geodatabase create a new feature class. Here you specify what kind of coordinate system your data is going to be in.

Georeferencing Part 1

Georeferencing Part 1
Using the View drop down and going to Toolbars- Georeferencing toolbar. This allows us to assign real world coordinates to our raster data, to a image that does not have real world coordinates, using control points.
Starting in the display window layer of our real world coordinates we ‘fit to display’ our new data to display an overlap. Here we can reference non real world to real world starting with the unknown using control points. You have to use more control points if your map is not very accurate.
We create a world file by Updating Georeferencing

Discussion Questions

Should you define a coordinate system when you don’t know its origin? What kinds of problems could occur?

Walk me though how she narrowed down her search in defining her data for Ohio.

Give me an example of when you would use NAD83 and WTD84 interchangeably and when should you not. Explain.

What is the difference between Coordinate systems and special reference?

Here we go

I'm very excited about this starting GIS class. The more I read about it the more I'm enthralled with the software.