Hi there, I'm working on a project for school and was hoping someone could help me out. I'm sure it's fairly easy, just not sure what the best method is. I downloaded a shapefile from here ('Curvas de nivel') which contains elevation data about the contours of Mexico. I'm hoping to convert that to a series of polygons so I can fill in a background colour for various increments to create a simple topographic map. What's the best way to do that? I know I can select by elevation, convert that to a new shapefile and apply the "Feature to polygon" tool to create a layer with a solid background colour and stack them up on each other. I'd like a way that's a little more dynamic though so I can modify the intervals without having to go through all these steps repeatedly. How can this be done? If any additional information is needed or I'm missing important details, please let me know. Thanks!
Since I not quite sure what you're after, here' a link to a previous thread that discusses contours and various solutions for polygonizing and systematically symbolizing them:
Essentially you should be able to make each interval into a polygon with the elevation as an attribute and then select and symbolize various intervals any way you like.
Have you tried applying a color ramp to the raster data directly? The layer properties > symbology tab allows for control of how a raster is displayed. You can set the number of colors, the range of values for each, and what each color is. Or select a ramp and stretch it across your data. Converting to polygons adds a great deal of work if all you need is a set of background colors.
I agree with Mark. Instead of downloading a contour shapefile, find a digital elevation model (DEM) and either symbolize it according to elevation, or create contours from it, or both (personally, I often like seeing both).
