GIS Final Map

Final Project Map

Lab #10

Geoprocessing- Geoprocessing takes an input dataset, performs an operation on that dataset and returns the result of the operation as an output dataset. Common actions are to include a geographic feature overlay, feature selection and analysis, topology processing, raster processing, or data conversion.

Model- One process or a sequence of connected processes in ModelBuilder.

Multipart polygon- A digital representation of a place or thing that has more than one part but is defined as one feature because it references one set of attributes. This can be a point, line, or polygon.

Discrete Data- Data that represents phenomena with distinct boundaries. Example include property lines and land-use areas.

Continuous Data- Data that varies without discrete steps such as temperature and elevation data.

Esri Grids- This is a way that Esri stores raster data that defines geographic space as an array of equally sized square cells arranged in rows and columns. When the grid is on the map, cells are assigned colors according to their numeric values and each grid is references by its x,y coordinate location.

No Data- The absence of recorded data in raster data. This does not equate to a value being 0. The measurement just has not been taken for this cell.

Neighborhood- User-defined are used to establish new output values. Neighborhood functions establish new values for locations use the values of other locations within the given area.

Intermediate Data- Any data in a process that did not exist before the process existed and that will not be maintained after the process is executed.

Reclassification- Process of taking input cell values and replacing them with a new output cell values. This is used to simplify or change the interpretation of raster by changing a single value to a new value or grouping ranges of values into single values.

1.      Explain how dissolve works.

a.       Dissolve merges polygons together to create a larger polygon that incorporates all of the areas data through specific common characteristics. For example, if there are over lapping layers, they would be merged into one single polygon rather than have polygons overlapping one another.

2.      Give one example of when to use dissolve and when to use clip

a.       You would use dissolve rather than clip when trying to merge data together. With dissolving you are incorporating the data that is related together. When clipping, it is like cutting out the data that you are not trying to focus on.

3.      Give two different applications for the buffer tool

a.       One application of buffers is for magnitude of earthquakes. The circles around origin of an earthquake radiating out are buffers because they are a constant distance around the feature. Another application of buffers could be for strength around a cell tower. There would be a constant distance around the cell tower.

4.      What is the difference between union, intersect, and merge?

a.       Union is when the polygons are joined together and new polygons are made where the first polygon does not overlap anything, the second polygon does not overlap anything, and the area of overlap between the two polygons. An intersect only shows the area of polygons where they intersect or overlap. A merge just combines the two polygons to create a new shape.

5.      Give an example of when you would use union over merge

a.       An example of when I would use union over merge would be if I am comparing two different events that happened in the same area. For example, if there was a fire that occurred on a hillslope and I was showing the extent of that with the incident of a slope failure. It would be helpful to see a union of the two separate events in order to see the extent of each rather than merging them together.

6.      Is the clip tool used for only vector, only raster, or both?

a.       The clipping tool can only be used for vector data. Arc GIS specifies that the data can be points, lines, or polygons which are vector data only.

7.      What might you use a mask for?

a.       I might use a mask when I have a lot of data but I only need a certain amount. The mask will take that portion of data that is needed and match the extent to other data that I am used for a specified area.

8.      How are environment settings use in arc map?

a.       The environment setting is used to match the ArcMap session and all the tools that I am currently using in the model.

9.      What might be an advantage of using model builder?

a.       An advantage to using model builder could be that it allows you to organize the inputs, tools, and outputs that will be used to perform the analysis.

Final Project Preview

Zombie vs Vampires

The interpolation approach that is best suited for the extent of the data set would be Inverse Distance Weighted. I think that we have enough points and that they are close enough to that this method would work best with the specific data set. The points in the data set looked evenly spaced out and that is the type of data that should be used for that set of sample points. However, the drawback to using IDW would be that it does not look at all of the data trends when interpolating the data.

Based on last year's precipitation events, the Amador-Calaveras area could experience even more drought for the recently burned area. Although the areas that do receive decent rainfall could potentially have a variety of earth flows and slides because the soil is compacted to the ground and is riddled with burned dead material. The soil is no longer being held together by the roots of the vegetation that was once there. The areas that are not as burned and affected by the fire would still have some ability to hold the soil together and therefore would be more stable and be less susceptible to mass movements when precipitation does arrive. Granted in order for mass movements to occur there would have to be an intense amount of precipitation that would saturate the soil enough to cause instability. Although the soil is less stable due to the recent fires in the area.

Aftermath of the Butte Fire

I chose to utilize the before (August NDVI) and after (September NDVI) to portray the loss of vegetation in the most simplest way possible. My map is oriented in a way that frames the before and after data of Normalized Difference Vegetation Index because it shows how the fire burned through the vegetation and caused the NDVI to shift. It is easily identified that the shift was from high NDVI to low NDVI from the stark color change. The two maps show the change that the fire caused. There is a large difference between the NDVI as can be seen from the large color change within the fire perimeter. From the two images one can see that there is a huge loss of vegetation. I also added a little comment about what NDVI is and what the different values mean because it might be confusing the people who are no familiar with the index and the way the data was collected.

I also chose to make an extent map that displayed where the fire was in relation to California but also on the smaller extent to show where the fire within Amador- Calaveras county. I assumed that this map would be only viewed by Californians because it is one specific fire within California during this year. This helps the readers of the map locate exactly where the fire was in relation to where they are. It is obvious that the fire burned a very large area within Amador-Calaveras County, over 70 thousand acres burned. It will take many years until the area will be back to its state before the fire. The topography of the area did not help with containing the fire due to the terrain.

Lab 5 Digitizing

 Exercise 13A 

Exercise 13B

Definitions of the Key Words from Chapters 11, 12. 13

Feature Dataset- a dataset that has related feature classes that can be grouped together

For example, we have a shapefile with streets and we combined that dataset with a shapefile that has all stop signs as points. This would create a new feature dataset.

Attribute Domain- established and enforces valid values or ranges of values for an attribute field

This would be used to fix the correct values that can be inputted for a attribute. For example, if we were talking about computers being occupied the two domains would be occupied or vacant and no other values could be put into the attribute.

Digitizing- drawing on top of maps, aerial, or satellite images with digital devices

For our class, we use digitizing on the computer and trace on aerial photographs, scanned maps, and other spatial data.

Vertex- points that define a line or a polygon

An example of this would be when we are tracing polygons, we plot vertices around the polygon to create a shape.

Endpoints- points that mark the end of a line segment

We use endpoints when we are drawing lines such as streets from point A to point B. Endpoints are also used when polygons are drawn using the editing tool.

Edge- segments between vertices

The edge is used when we are drawing polygons. They are also the sides of the polygons.

Edit Sketch- this is before a feature is saved when drawing a polygon or during an edit session

This is when the polygon you have drawn is highlighted in blue in ArcMap.

Edit Session- when you click start editing and in this mode one can add features or modify features

Edit session is used when we want to trace around features for example in these lab exercises we used it to trace around playgrounds.

Snapping- editing operation where points or features within a specified distance are moved to match with each other’s coordinates

We use snapping to only show features where we are currently working or looking at. For example, during chapter 12 we were only looking at streets that were relevant to what we were doing.

Map Topology-temporary set of topological relationships between parts of simple features on a map that will behave as if they are connected

We used map topology in chapter 13 when we changed the boundaries of the neighborhoods because when we moved that edge it changed the shape of both polygons where the edge was touching.

Geodatabase Topology- arrangement that constrains how point, line, polygon, features share geometry, allows you to enforce rules within and between feature classes

You can use this to manipulate maps to be exactly how you want by enforcing rules. An example would be that you want all your lines to be connected. This is a faster way to ensure that your map will be the product you want. 

Which California Counties Received Drought Aid in 2014?

The question I was trying to answer with this map was, which counties received aid for the extreme drought in 2014? I chose the choropleth scheme of qualitative because it displayed the information in the least confusing way possible. I decided that the best way to convey the drought aid data was to only show two colors on my map. It clearly shows which counties received aid and which did not for that specific month. The color red was used because I was linking the color with the idea that the drought is bad and that it has become even worse as the year has progressed. My extent map is showing where California is in relation to the west coast of the United States for people who do not know where California is. I chose this extent because I assume that people already know that California is on the west coast of the United States. I chose to create three maps because it made the message of which counties received aid the most clear. When the different months were layered over each other, the message was confusing to which counties received aid in a specific month. The three maps takes away the confusion of the overlap.

The intended application of this map is for viewers to see the different counties in California that received aid in 2014. It allows the viewers to understand how the drought progressively intensified as the year 2014 continued. This map also shows viewers which counties were hit harder by the drought in relation to other counties in California. This map could be used for policy makers and land managers because they can easily see where the problem areas of drought are. This would make it easier for them to apply drought restrictions for water usage. Other intended audiences for this map would be citizens of California and the surrounding states. This would effect the citizens' water usage around the drought areas. This map would be considered a time series analysis due to the fact it is comparing different times within the year 2014. The intended purpose influenced the map style because the message had to be clear enough for viewers to understand. The separation of the three different months was influenced because when they were layered upon each other the message was not as clear.

California's Drought

The question that I was asking with this map is how bad has the drought become after a couple years in California. I started with the map for 2015 first and after I perfected it then I created the map for 2012. After the two data frames were created, I then added finishing touches to the complete map. I also created an extent map for people who are not familiar with the western side of the United States. As you can see since the 2012, the drought has become more severe in California. The measurement for the map is the intensity of the drought on a scale of 0-4 on the drought meter.

This map could be used by land management and policy makers to see which counties would need the biggest water restrictions. This map could also be used by the general public to see the conditions of the drought and how it affecting different parts of the state and specific counties. This map can help to shape how the state uses water and how much water is being used in the future. The information from this map can really show the affects of the drought and can have an effect on the public and how their usage of water.

State Parks and Faults

I was questioning how state parks might be effected by the potential danger of faults that run throughout the state of California. This map shows the proximity of faults to northern California state parks. Faults could be dangerous because if there is movement within the fault it could cause harm to people that are visiting those state parks.

This map could be potentially useful to visitors of state parks because if there is a lot of earthquake activity then they may not want to visit a state park that is close to a fault. This map could also be useful to state planners who are planning to create state parks because they may not want to establish a park close to fault lines due to the potential danger of a major earthquake.

I chose to leave out information such as California counties, Geology of California, and California vegetation because they were not relevant to the question that I was asking and the message that I wanted to convey with my map. The fault lines are in the color red because this color really draws the attention of the viewer to the faults and the yellow for the state parks pops out as well to catch the attention of the map users.