The ratio between distances on a map and distances in the world

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11
votes
4answers
440 views

How to generalize coastlines?

I have a large set of data points that essentially represent the coastline of the world. I don't know the exact resolution but I'd say it's in the neighbourhood of 5-10m. Imagine a set of points ...
5
votes
1answer
286 views

How to fix distortions in rendered OpenStreetMap maps?

I use OpenStreetMap in order to generate maps and add some cool stuff in it. Actually I have good results but I seem to have a problem with reporting a good image ratio when I create my generated ...
2
votes
0answers
2k views

How to zoom exactly to a desired scale in Flex?

I am using ArcGIS API for flex 2.4 with ArcGIS server 10. I am trying to write the widget where user can define the map scale (type it in text box) and it will zoom to that scale. I successfully ...
3
votes
1answer
1k views

Mapserver, TMS, Scales zoom levels and how to deal with all of it

I have a whole bunch of data in my db that I need to draw at different zoom levels using Mapserver. Everything uses a 4326 SRID. My (custom) client, will fetch the data using 20 TMS zoom levels and ...
7
votes
3answers
366 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
496 views

Displaying features at map scale corresponding to attribute?

Suppose one had a large dataset of features of vastly different sizes - perhaps political boundaries ranging from country to county. It would be useful to be able to display only the large countries ...
35
votes
10answers
63k views

What ratio scales do Google Maps zoom levels correspond to?

Can anyone provide me with a link (or some details) on the actual ratio to "zoom level" figures for Google Maps? e.g. Google Maps Level 13 = 1:20000
12
votes
1answer
446 views

Scale in printed map (mxd) is different in code to manual printing

This question is related in part to a previous question I have asked. I have tried printing an A3 mxd with the Print Active View code as published by ESRI and have changed only one line of code and ...
7
votes
6answers
818 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 ...
10
votes
2answers
1k 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 ...
3
votes
1answer
1k views

MapInfo Bing Aerial resolution/scale

I am using MapInfo to display some Bing aerial photos. It seems as if it is using the wrong scale of imagery - they look blurred, as if the image has been enlarged. Is there a way to force it to use ...
2
votes
1answer
656 views

I have several layers (polylines and polygons) that are of the same area but they don't overlap in ArcMap as they should, what do I do?

For my GIS project for my class, I have downloaded several vector layers from different websites (polyline of the continental divide, a boundary polygon of New Mexico, a rivers and water bodies layer ...
3
votes
2answers
649 views

Silverlight Map with ESRI Imagery

I have a map service which is using data from a local repository, viewed using the ESRI Silverlight API. I am dynamically adding a tiled map service for imagery from ESRI. The map service can be ...
2
votes
2answers
1k views

MapServer computes wrong map scales — off by factor 0.77. Or is it just me?

I've noticed in a current project that MapServer seems to get the map scale wrong, or then I'm wrong, but don't see how. My mapfile contains the following definitions: RESOLUTION 72 # this is the ...
7
votes
2answers
12k 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 ...
4
votes
2answers
1k views

Custom scalebar units in ArcMap

Is it possible to create a scalebar in ArcMap that shows distances in custom units? I understand how to do this manually, but it would be great if I could define a custom unit of measurement (let's ...