Lab 2
Lab 2
GEOG 337
Due 2/25/2018
Jeffrey Hessburg
This lab entails accurately georeferencing a historic 1878 map Eau Claire. Georeferencing is a tough task to do because there is a lot of room for error. Essentially georeferencing is giving raster data a spatial location. Using the georeferencing tool in ArcMap, it can be done.
The first task in the lab is to add the data and answer why you entered this data is a certain order. the reason for this is because the raster data has to be given a coordinate system, it will automatically be added to the first layer put in ArcMap.
The next step is to actually georeference the map. To do this we use the already referenced base-map, and map of the roads. We must find points on the 1887 map of Eau Claire that correspond to the points on the base-map and road map. This was the hardest challenge. The 1887 map has different some different roads, and road names so it is difficult to find points that correspond. It is also important to find points that are spread out. I used 4 points, one in each corner of the map. This is known as first order transformation. After attempting this several times, I finally found points that aligned well enough. It is, however, not perfect. The map shows how well it actually lined up.
The next objective was to create a polygon feature. To do this open ArcCatalog. Next find the desired location of where you want to save the feature class. Right Click and select, new > File Geodatabase. Then open that file geodatabase, right click: New > Feature Class. Name the Feature class then select the correct coordinate system. Once the feature classes are created it is time to started editing. The goal is to turn the rivers and lakes from 1887 and 2018 into polygons. To do this open the editing toolbar, open Create Features, select the layer that is desired to create the polygons in, go to the construstion tools and select polygon. Next, place nodes along all of the water bodies to create the polygons.
Once the layers are made it is time to analyze the results. When the 1887 and 2018 water bodies are displayed both at the same time, the differences are clear to see. The shape of the water bodies have changed a lot in the last 140 years. By opening the attribute table, it is possible to see the difference in area between the 1887 water bodies and the 2018 water bodies. These results will vary from student to student because everyone is going to place nodes in different places so the results will be slightly different. The map below shows how the water bodies have changed.
Sources:
1. David Rumsey Map Collection https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~4181~480085#
2. Master_Centerlines feature class (clipped), Eau Claire County
3. World Topographic Map, ESRI, 2018: https://www.arcgis.com/home/item.html?id=30e5fe3149c34df1ba922e6f5bbf808f
GEOG 337
Due 2/25/2018
Jeffrey Hessburg
This lab entails accurately georeferencing a historic 1878 map Eau Claire. Georeferencing is a tough task to do because there is a lot of room for error. Essentially georeferencing is giving raster data a spatial location. Using the georeferencing tool in ArcMap, it can be done.
The first task in the lab is to add the data and answer why you entered this data is a certain order. the reason for this is because the raster data has to be given a coordinate system, it will automatically be added to the first layer put in ArcMap.
The next objective was to create a polygon feature. To do this open ArcCatalog. Next find the desired location of where you want to save the feature class. Right Click and select, new > File Geodatabase. Then open that file geodatabase, right click: New > Feature Class. Name the Feature class then select the correct coordinate system. Once the feature classes are created it is time to started editing. The goal is to turn the rivers and lakes from 1887 and 2018 into polygons. To do this open the editing toolbar, open Create Features, select the layer that is desired to create the polygons in, go to the construstion tools and select polygon. Next, place nodes along all of the water bodies to create the polygons.
Once the layers are made it is time to analyze the results. When the 1887 and 2018 water bodies are displayed both at the same time, the differences are clear to see. The shape of the water bodies have changed a lot in the last 140 years. By opening the attribute table, it is possible to see the difference in area between the 1887 water bodies and the 2018 water bodies. These results will vary from student to student because everyone is going to place nodes in different places so the results will be slightly different. The map below shows how the water bodies have changed.
Sources:
1. David Rumsey Map Collection https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~4181~480085#
2. Master_Centerlines feature class (clipped), Eau Claire County
3. World Topographic Map, ESRI, 2018: https://www.arcgis.com/home/item.html?id=30e5fe3149c34df1ba922e6f5bbf808f
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