arcgis-desktopdataelevationshapefile
I am a bit new to ArcGIS and have run into a snag.
I have a series of points in a shapefile that only have x and y coordinates. Additionally I have a series of other points in a separate shapefile that have x, y, and z coordinates. I have added both to a map and have generated contours from the latter of the two files.
My question is: Is it possible to determine the elevations of the points in the first shapefile based on the second shapefile and contours and if so how?
When generating shaded reliefs it's important to transform the elevation models from geographic lat-long to a metres based projection, Albers, Lambert and Mercator work well, else you end up with horrible shadows and gross east-west stretching deformaties. Transform the reliefs back to decimal degrees afterwards if necessary. Also instead of accepting the default 45° sun angle put it higher in the sky, about 70°, and an upper left aspect, about 315°.
I assembled the Geobase elevation models into larger tiles which are somewhat easier to use, see http://www.maphew.com/Projects/Canada_50k_Digital_Elevation_Model. The storage resolution (pixel dimensions) is 16 metre cells, not to be confused with nominal resolution which ranges from 10m to 30m+ depending on original data source and latitude.
update: here is a sample generated from 105G08 freshly downloaded from Geobase and using the above parameters in Spatial Analyst's Hillshade. Screen clip captured from Arcmap at "zoom to raster resolution" scale.
One option would be to compare the algorithms to your GPS tracks using a program such as GPS Visualizer. This program allows you to incorporate the best available DEM elevation data (i.e. usually 30m resolution) with your GPS data to produce an elevation profile. From there simply compare the min/max/range etc.
Best Answer
Assuming that the 3D analyst Extension is available, here is how I would solve the problem:
Using the shapefile containing the heights, I would interpolate and create a DEM. There are many tools for this, such as IDW, Spline and Trend, but I would suggest that you use Topo to Raster tool. In My experience, this produces the most realistic output amongst all the tools.
Once you have the DEM raster, use the Extract Values to Points tool, to get the Z values for the input points(the shapefile having only x & y)