Lab 5 part 2
2.
a. Basemap, Hydrology
b. NHDFlowline, NHDPoint, NHDWaterbody, Watersheds.
c. line, point, ploygon, polygon
3.
a. Vector digital data
b. Shapefile
c. yes
d. ArcGIS Geodatabase
e. yes
f. Hydrography, Stream/river, Lake/pond
g. USGS, EPA & USDA
4. a. yes
*Note: Link to CASIL website says its broken*
Thursday, September 30, 2010
Lab 5 part 1
1. The advantages of using digital spatial data are that its low cost easy and quick to get a lot of spatial data and are provided in efficient forms like GPS. The disadvantages are that it is time consuming to gather data and not everything is include yet.
2. The most important question we ask our-selves when using already developed spatial-data are does it contain the information I need and is it free.
3. DOQ’s are photographic images that have been corrected for distortions due to camera tilt and terrain displacement, then georeferenced.
4. The National Hydrological Dataset is produced by the United States Geological Survey and the sources are a combination of USGS hydrologic digital line graph files and EPA reach files. The USGS files are used for spatial accuracy and the EPA files are used for attribute information. It uses North American Datum of 1983. It is a comprehensive set of digital spatial data representing the surface water of the United States using common features such as lakes, ponds, streams, rivers, canals, and oceans.
The Geospatial Data Gate way is by the United States Department of Agriculture and its source is the National Resources Conservation Service and it contains environmental and natural resources data.
The Geocommunity Data Depot is a source for SDTS format DEMs from the USGS. It also has lots of data sets downloaded from all over the Internet and is easy to access and is run by the Mindsites Group.
5. DEMs are older and need to be put together like tiles in a mosaic for large areas because they had fixed boundaries. NED provided a seamless data set in high resolution and new algorithms to remove errors created by the advancement in technology.
1. The advantages of using digital spatial data are that its low cost easy and quick to get a lot of spatial data and are provided in efficient forms like GPS. The disadvantages are that it is time consuming to gather data and not everything is include yet.
2. The most important question we ask our-selves when using already developed spatial-data are does it contain the information I need and is it free.
3. DOQ’s are photographic images that have been corrected for distortions due to camera tilt and terrain displacement, then georeferenced.
4. The National Hydrological Dataset is produced by the United States Geological Survey and the sources are a combination of USGS hydrologic digital line graph files and EPA reach files. The USGS files are used for spatial accuracy and the EPA files are used for attribute information. It uses North American Datum of 1983. It is a comprehensive set of digital spatial data representing the surface water of the United States using common features such as lakes, ponds, streams, rivers, canals, and oceans.
The Geospatial Data Gate way is by the United States Department of Agriculture and its source is the National Resources Conservation Service and it contains environmental and natural resources data.
The Geocommunity Data Depot is a source for SDTS format DEMs from the USGS. It also has lots of data sets downloaded from all over the Internet and is easy to access and is run by the Mindsites Group.
5. DEMs are older and need to be put together like tiles in a mosaic for large areas because they had fixed boundaries. NED provided a seamless data set in high resolution and new algorithms to remove errors created by the advancement in technology.
Wednesday, September 29, 2010
Lab 4 part 3
1. An ellipsoid, or spheroid, is an m mathematical surface defined by revolving an ellipse around its minor (polar) axis. It differs from a sphere because it has a bulge in the middle, the Earths orbit is an ellipsoid.
2. Latitude and Longitude lines are know as the Cartesian Coordinate System
3. The geographic North Pole is where the lines of longitude converge at the top of the globe. Magnetic north is where our compasses point to and is the axis of the Earth rotation
4. Datums are important because are 3-D frames of reference used to determine surface locations or it orientation with lines of latitude and longitude. They are created through geodetic surveying and monument points.
5. Map Projections are the transformation of coordinate locations from the earth’s curved surface onto flat maps.
6. A developable surface it is "surface" that can be flattened onto a plane without distortion
7. Lines of Longitude run north-south
8. Clarke 1866 would be great for modeling N. America because its for local areas
9. The best coordinate system for mapping countries and large areas is the Universal Transverse Mercator System or UTM. It is a global coordinate system which is better for areas spanning large regions.
10. The great circle distance is the shortest distance between any two points on the surface of a sphere measured along a path on the surface of the sphere
1. An ellipsoid, or spheroid, is an m mathematical surface defined by revolving an ellipse around its minor (polar) axis. It differs from a sphere because it has a bulge in the middle, the Earths orbit is an ellipsoid.
2. Latitude and Longitude lines are know as the Cartesian Coordinate System
3. The geographic North Pole is where the lines of longitude converge at the top of the globe. Magnetic north is where our compasses point to and is the axis of the Earth rotation
4. Datums are important because are 3-D frames of reference used to determine surface locations or it orientation with lines of latitude and longitude. They are created through geodetic surveying and monument points.
5. Map Projections are the transformation of coordinate locations from the earth’s curved surface onto flat maps.
6. A developable surface it is "surface" that can be flattened onto a plane without distortion
7. Lines of Longitude run north-south
8. Clarke 1866 would be great for modeling N. America because its for local areas
9. The best coordinate system for mapping countries and large areas is the Universal Transverse Mercator System or UTM. It is a global coordinate system which is better for areas spanning large regions.
10. The great circle distance is the shortest distance between any two points on the surface of a sphere measured along a path on the surface of the sphere
Lab 4 part 2
The reason we use map projections is because some surfaces that are not flat, i.e. a sphere, need to be represented in a two dimensional form. This two dimensional form is that of a flat map and projection distorts the image of the three dimensional object so the surface will appear flat. Depending on the function of the map some distortions are acceptable and some are not. So some maps preserve the actual size of the geographic features on the map and distort the traditional square looking maps and some preserve the traditional style by sacrificing the actual shapes of the features and distances. We can compare the styles and their accuracy by measuring distances on the maps from one city to another, in this case from Washington D.C. to Baghdad, Iraq which is 9977 kilometers apart.
The first style of conformal map projection preserves angle and shape. The first type of conformal map is the Mercator map. This map is preserving the shape of the major continents, however it makes the regions of the Antarctic extremely oversized compared to the rest of the continents, as well as Greenland but not to that extent. The distance from D.C. to Baghdad is 13,614 km, which is way over. The second type of conformal map is the Gall Steriographic. It to shows the continent of Antarctica and Greenland over sized however Antarctica is a little smaller this time, the distance between D.C. and Baghdad is much closer to the real figure at 9,565 km, which was a surprise to me.
The second kind of map projection is the Equal Area map which preserves the area of the features on the Earth. The first style of Equal Area map is the Bonne map. It looks like a giant heart but now the continents are more proportional to each other with Antarctica and Greenland now their regular size. It is however hard to see Australia and surrounding islands but you have a very good view of the northern hemisphere. The distance from D.C. to Baghdad is also closer at 9,345 km. The second style of Equal Area map is the Hammer. The map now resembles what the globe actually looks like in sort of a football shape with all continents visible and comparatively similar. D.C. to Baghdad is over at 11,210 because the areas are equal not the distances.
The last type of map projection is the Equidistant map. It preserves neither area nor shape but preserves distance over a short area. The first style of Equidistant map is the Equidistant Conic map. This map looks like you took a globe and butterflyed it with a knife and smashed it flat. The map is cut in the Pacific Ocean and leaves a good 45-degree section off. The continent of Antarctica is now greatly oversized again. The distance is now the closest to the real figure at 10,073 km, which is what I would expect. The second style of Equidistant map is the Equidistant Cylindrical map. For some reason this Equidistant map looks almost exactly like the Gall Steriographic map. Its not though because the map seems more stretched vertically. When I looked at the definition on Wikipedia its like they cut the globe up into a tube like shape and then it’s as if they roll it on a flat surface. The distance from D.C. to Baghdad is extremely under at 6,776 km. This could be because these maps are supposed to be good for short distances.
Wednesday, September 15, 2010
Lab 3
1. A Data Model is a set of rules/constructs used to describe and represent aspects of the real world in a computer. The two most common types are Raster and Vector.
2. Topology is the study of geometric properties that do not change when the forms are bent, stretched or undergo similar geometric transformations. It is important because it captures and records the relationships between features.
3. A Raster data model would be better for representing a hillside slope because it can more accurately represent continuous areas.
4. Each cell can only hold one spatial detail value, for example a minimum line width is one cell.
5. The four types of attribute data are: Nominal, ex. soil type. Ordinal, ex. erosion class value. Interval and Ratio, ex. area or length of erosion site.
6. Two types of vector data file formats are shapefiles and coverages.
7. Two types of raster data file formats are grids and images like jpegs.
8. You can not select features in ArcCatalog.
9. The World.mdb contains 4 feature classes.
10. The feature classes in World.mdb are, cities, countries, disapp_area and world30.
11. The flight_path.lyr file refrences a shapefile.
12. To add data to ArcMap you can open it from ArcCatalo with a data file or click add drag.
13. I thinks there are 699 features in dissap_area, you can get the info from AcrCatalog by looking at the metadata.
Thursday, September 9, 2010
Lab #2
1. Some of products that come with the ArcGIS software are ArcMap, ArcCatalog, ArcView and ArcEditor. We will be using the ArcMap application mostly because it is what we use when we are viewing and analyzing data, editing, and creating maps, graphs and reports.
2. It is better to perform data analysis and layer symbolization in data view because data view is for those functions; layer view is for composing maps for printing by adding titles and other elements.
3. To obtain help in ArcGIS is to use the “What’s this function” or by going to the ArcGIS help center by clicking help.
4. Attributes describe the geographic feature, for example the population, rainfall, and elevation are attributes of cities.
5. File extensions let you connect to the content of a file faster by un-hiding the extension.
6. Two ways to zoom in or out are the zoom tool and the full extent button.
7. Three operations in the context menu of a layer are, zoom to layer, open attributes table and label features.
8. When a check box next to a layer is grayed out it means its visibility depends on the map scale being smaller, indicated by a small scale bar underneath. You can zoom in on the area and the gray will disappear.
9. Large scale maps define a smaller area for maps like hiking maps (ex. 1:10,000). Small scale maps define larger areas like driving maps (ex 1:1,000,000).
10. A surface is an area with a texture like the plains or the ocean. A feature is a specific thing on the surface like a mountain or a river known as “surface features”
11. GIS cannot create a project’s criteria, that is our job.
12. The city with the max elevation was Tucson at 1045km, and the lowest city was The Big Easy at 0. To figure this out I right clicked the cities visited layer, open the attributes table, right click on the elevation attribute and chose either sort in ascending or descending order.
13. The two techniques I used to find the distance from Dakar to Assab was to use the measure tool in tool box and clicked on the cities (aprox. 6,707km). The second was to look at the attribute table for flight path and add the distances from city to city (aprox. 6,898 km).
14. Two was to find the name of the cities would be to click the far left gray box in the attribute table next to cities name and look at map, or use the I.D. tool.
15.
1. Some of products that come with the ArcGIS software are ArcMap, ArcCatalog, ArcView and ArcEditor. We will be using the ArcMap application mostly because it is what we use when we are viewing and analyzing data, editing, and creating maps, graphs and reports.
2. It is better to perform data analysis and layer symbolization in data view because data view is for those functions; layer view is for composing maps for printing by adding titles and other elements.
3. To obtain help in ArcGIS is to use the “What’s this function” or by going to the ArcGIS help center by clicking help.
4. Attributes describe the geographic feature, for example the population, rainfall, and elevation are attributes of cities.
5. File extensions let you connect to the content of a file faster by un-hiding the extension.
6. Two ways to zoom in or out are the zoom tool and the full extent button.
7. Three operations in the context menu of a layer are, zoom to layer, open attributes table and label features.
8. When a check box next to a layer is grayed out it means its visibility depends on the map scale being smaller, indicated by a small scale bar underneath. You can zoom in on the area and the gray will disappear.
9. Large scale maps define a smaller area for maps like hiking maps (ex. 1:10,000). Small scale maps define larger areas like driving maps (ex 1:1,000,000).
10. A surface is an area with a texture like the plains or the ocean. A feature is a specific thing on the surface like a mountain or a river known as “surface features”
11. GIS cannot create a project’s criteria, that is our job.
12. The city with the max elevation was Tucson at 1045km, and the lowest city was The Big Easy at 0. To figure this out I right clicked the cities visited layer, open the attributes table, right click on the elevation attribute and chose either sort in ascending or descending order.
13. The two techniques I used to find the distance from Dakar to Assab was to use the measure tool in tool box and clicked on the cities (aprox. 6,707km). The second was to look at the attribute table for flight path and add the distances from city to city (aprox. 6,898 km).
14. Two was to find the name of the cities would be to click the far left gray box in the attribute table next to cities name and look at map, or use the I.D. tool.
15.
Thursday, September 2, 2010
Real world GIS applications
uky.edu/geography/studentprojects
This GIS map shows the expedition routes and direction that explorers took when exploring Australia's outback in the 17th century. It also shows major cities, rivers, deserts and plains.
realworldgis.com/outbackaustralia
This GIS map shows the change in simulated crime patterns for Leeds in the United Kingdom in regeneration sites before and after the regeneration. Regeneration is when an area is cleaned up, commonly known as gentrification.
2.bp.blogspot.com
GIS definitions
A geographic information system (GIS) integrates hardware, software, and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. GIS allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.
Gis.com/content/what-gis
A geographic information system (GIS), or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location. In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology. GIS systems are used in cartography, remote sensing, land surveying, utility management, natural resource management, photogrammetry, geography, urban planning, emergency management, navigation, and localized search engines.
Wikipedia.org/gis
Mobile GIS (geographical information system) is the use of geographic data in the field on mobile devices. It's an evolution of how the enterprise database is used and managed within an organization. Mobile GIS integrates three essential components; Global Positioning System (GPS), rugged handheld computers, and GIS software.
Trimble.com/mobilegis
The similarities between these definitions are that they all use the same meaning for the acronym for GIS. The first two definitions are from educational web sites and the third is from a company that makes GIS tools. The educational definitions are very similar using the same terminology like capturing, managing and analyzing. They both refer to maps or cartography. The differences are that the Wikipedia definition seems to be the most descriptive giving us examples of what GIS is used for and gives us the alternate term “geospatial”. The Trimble definition gives us a real world example of the three components to using mobile GIS in the field, talking about hardware and software. The GIS.com definition, also refers to soft and hardware and is the simplest and the closest to the class definition. This tells us that GIS is a relatively broad term that can have varying definitions and functions in real world applications.
Gis.com/content/what-gis
A geographic information system (GIS), or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location. In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology. GIS systems are used in cartography, remote sensing, land surveying, utility management, natural resource management, photogrammetry, geography, urban planning, emergency management, navigation, and localized search engines.
Wikipedia.org/gis
Mobile GIS (geographical information system) is the use of geographic data in the field on mobile devices. It's an evolution of how the enterprise database is used and managed within an organization. Mobile GIS integrates three essential components; Global Positioning System (GPS), rugged handheld computers, and GIS software.
Trimble.com/mobilegis
The similarities between these definitions are that they all use the same meaning for the acronym for GIS. The first two definitions are from educational web sites and the third is from a company that makes GIS tools. The educational definitions are very similar using the same terminology like capturing, managing and analyzing. They both refer to maps or cartography. The differences are that the Wikipedia definition seems to be the most descriptive giving us examples of what GIS is used for and gives us the alternate term “geospatial”. The Trimble definition gives us a real world example of the three components to using mobile GIS in the field, talking about hardware and software. The GIS.com definition, also refers to soft and hardware and is the simplest and the closest to the class definition. This tells us that GIS is a relatively broad term that can have varying definitions and functions in real world applications.
GIS vs. maps
The similarities between GIS and maps is that they both look at the geography of the land and give use geographical information. They both use a grid to tell location in the form of latitude and longitude lines and they both use attributes to describe what the viewer is looking at. The differences between GIS and maps are that GIS uses layers of information for a specific purpose and can be interactive. Maps are usually two-dimensional representations of three-dimensional surfaces and are not interactive, printed on paper in a topographical style and created by cartographers.
Subscribe to:
Posts (Atom)