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

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3
votes
1answer
2k views

Openlayers + WMS layer. Use scale or resolution + DPI

I have a problem with displaying map with WMS layer in Openlayers. I'm able to display it but the image of the map is not sharp especially at higher zooms. I have a documentation from the map ...
1
vote
1answer
670 views

OpenLayers Scaleline always wrong in my virtual star map

I got a problem for the scale line when I using openlayer to show my "star map". Basically, I give a set of 2D coodinates (X,Y) for each star, and generate the map using map server. Now the map can be ...
3
votes
1answer
907 views

Changing the scale (generalisation) in ArcGIS 10

I have 2 polygon layers, accordingly 1:10 000 and 1:500 000. I want to generalize the first layer from 1:10 000 to 1:500 000. I tried using Simplify polygon tool, and since these scales relate to ...
4
votes
1answer
735 views

Find a suitable font size for the map scale?

Is there a website that suggests suitable font sizes for each scale level in the layout? I am currently using ArcGIS 9.3 but pretty soon will upgrade to 10. Thanks !
3
votes
1answer
358 views

What are some examples of model-based upscaling of raster data?

Remotely-sensed raster data may be too fine-grained for many purposes. A typical approach to coarsen the grain is to upscale by reducing the resolution. If the data are continuous (e.g elevation, ...
2
votes
1answer
501 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 ...
2
votes
0answers
454 views

How to calculate the scale of map tiles accurately?

In web maps, there are two coordinate: wgs84 geographic coordinate and web mercator project coordinate. The displayed scale of a world map is the value at equator, and one 256*256 pic can contain the ...
3
votes
2answers
339 views

What is the unit of measurement for scale?

Maybe this is standard across mapping engines, but in MapGuide if I set the scale to 7 million I can see about half the world. At about 4 million I can see a continent. What unit of measurement ...
5
votes
3answers
1k views

Using GIS for Interactive Floor Plan

GIS is brand new to me, but I've spent a couple of days researching so that I can at least ask somewhat intelligent questions. I've decided to use QGIS I need to do an interactive floor plan on the ...
8
votes
5answers
2k views

What are standard scales, or zoom levels, for map applications?

I am working on an ArcEngine program that is restricted to a set of scales. It currently has: 1:187.5 1:375 1:750 1:1500 1:3000 1:6000 1:12000 1:24000 1:50000 1:100000 I don't think there's ...
0
votes
1answer
155 views

How do I change the scale of one map sheet within a map series in MPS Atlas

I am using MPS Atlas and have a large map series (almost 300 map sheets) with the Areas Of Interest defined by the polygons of a feature class with a 100 m buffer on each polygon. This works well for ...
4
votes
1answer
2k views

How can I change the display name of the “Scale” control?

Here is the thing. I added the Scale control to my web and is displayed in a div at the bottom. I need to translate the "Scale" text to other language but I can't find how to do it. I searched in the ...
2
votes
2answers
4k views

ArcGIS javascript API - draw circle of a specified radius in meters

I am trying to add a circle of a specified radius (let's say 200 meters) to a map. My thought is to create a SimpleMarkerSymbol object. The constructor asks for a size of the symbol in pixels, but I ...
3
votes
2answers
3k 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 ...
4
votes
1answer
749 views

Dimensional analysis/conversion problem: Map scale to image resolution (dpi)

Given a map scale of 1:17,200 and a raster whose cell size is 6 inches, what resolution (dots per inch) should I choose when exporting the map to an image in order to maintain the raster's native ...
11
votes
4answers
413 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
216 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
343 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 ...
27
votes
8answers
39k 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
11
votes
0answers
416 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
683 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
634 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
624 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
943 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
10k 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 ...
3
votes
2answers
943 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 ...