4a there is no slope, the ground is a flat surace at that elevation
4b the elevation drops i think
Archive for February, 2011
What are the differences? the 5m contours are way more detailed and the further apart the contours get it gets less detailed
Were the results what you expected? yes
What are the 2 highest elevation points on the PG_Cont5_TIN? 885 and 880
1. TIN-(Triangulated Irregular Network) A vector-based data structure for storing terrain information in digital terrain modeling, it is a surface representation derived from irregularly spaced points and breakline features. Each sample point has an x, y coordinate and a z value or surface value.
2. Interpolated values-interpolation is a method of constructing new data points within the range of a discrete set of known data points, the interpolated values can be represented by color or number etc.
3. Mass points-An irregularly distributed sample point, with an x-, y-, and z-value, used to build a triangulated irregular network(TIN). Ideally, mass points are chosen to capture the more important variations in the shape of the surface being modeled.
4. DEM-(data elevation model)-a DEM file is a simple, regularly spaced grid of elevation points .A DEM can be represented as a raster (a grid of squares, also known as a heightmap when representing elevation) or as a triangular irregular network (TIN). The TIN DEM dataset is also referred as a primary (measured) DEM, whereas the Raster DEM is referred as a secondary (computed) DEM
5. Contiguous data-Data that are stored in a collection of adjacent locations in a computer memory device,
contiguous data is data that is moved or stored in a solid uninterrupted block. In general, contiguous data can be accessed more quickly than data that is stored in fragments because fewer access operations will be required. Files are sometimes stored in fragments so that storage space can be used more efficiently (all the small spaces can be used).
6. Re-sampling-can refer to re sizing of images or data sources it can also be a filter to the data and changes the sampling rate of the signal by decimation or interpolation.
7. Raster- Raster data is a grid of cells covering an area of interest. Each pixel, the smallest unit of information in the grid, displays a unique attribute.An example of raster data is a scanned image or photograph. A line drawn in a raster format must be defined by a group of pixels along the length of the line. As a result the size of a raster file is larger than that required by a vector file.
8. Cell-is a three-dimensional polyhedron element that is part of the boundary of a higher-dimensional polytope
9. Zone-a zone is an area of set perametres that has information inside of the certain area
for example pg is in utm zone 10, a specific area that has been divided out of the bc zones.
10. Grid-can be used to define locations on maps using Cartesian coordinates. Grid lines on maps define the coordinate system, and are numbered to provide a unique reference to features.
for example x,3 y,7
information from:
gislounge.com/triangulated-irregular-network-tin/
en.mimi.hu › GIS
www.wikipedia.org/
http://www.vterrain.org/Elevation/dem.html
http://www.answers.com/topic/contiguous-data
http://www.mathworks.com/help/toolbox/ident/ug/bqvevmu-1.html
http://www.cadresources.com.au/
http://www.google.ca/images?um=1&hl=en&rls=com.microsoft:en-us&q=utm%20zone&ie=UTF-8&source=og&sa=N&tab=wi
http://www.google.ca/
http://www.gis.com/
rednex4x4 