The ratio between distances on a map and distances in the world
2
votes
2answers
2k views
Why does QGIS scalebar show a wrong scale?
I'm using QGIS 1.7.1 and have added a scalebar. The scalebar usually displays in degrees, unless I switch the map's projection to meters, in which case the units are display in cm. This is not ...
7
votes
6answers
509 views
Maps zoomed around specific locations (magnifying glass effect)
How do I create a static map where the scale varies based on location?
Example: to drive from a specific location X in Albuquerque to a
specific location Y in Chicago, I want to "zoom" around X and ...
7
votes
2answers
6k views
OpenLayers: Use scales instead of resolutions
Venturing around in the OpenLayers source code, it seems like everything related to zoom-levels is done using resolutions. Fair enough since this related directly to screen space.
I would like ...
10
votes
2answers
809 views
Surface distance on DEM between two coordinates
Given two coordinates on a digital elevation model (DEM), how do I compute the actual distance traveled between the two locations, assuming a straight line route? How will changing the resolution of ...
7
votes
3answers
286 views
How to handle display of nested polygons (census, county/state, etc) for a given map extent
My question is how best to decide which layer (from a set of nested, aggregated census polygons) to display for any given map extent in an online map.
Australia's census boundaries are built from ...
2
votes
1answer
198 views
How to show labels depending on the zoom scale and save it forever in one project?
I have got a problem in showing labels for a polygon layer :
When I select "Show labels" in the layer's properties, then I select that I want to use the scaling to show or not my labels and I ...
