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

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27
votes
8answers
38k 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
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 ...
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 ...
10
votes
0answers
407 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 ...
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 ...
7
votes
6answers
675 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
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 ...
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 ...
7
votes
2answers
210 views

What does map scale refer to in map making / field survey metadata?

If I have, say, a printed map at the scale of 1:20000 and the legend says that it was mapped at a scale of 1:10000 does this simply mean, that the surveyors/cartographers made drafts & sketches or ...
6
votes
2answers
1k views

How to create a vertical scale bar in ArcMap?

Wondering if anyone out there knows how to create a vertical scale bar in ArcMap? With text I can adjust the angle. Is this possible with a scale bar as well?
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 ...
5
votes
3answers
173 views

How to know if shapefile is georeferenced?

I have a shapefile which is located in province in indonesia. it contains many sub-province if i removed sub regions inside a shapefile, and it leaves a small region, and my question is that small ...
5
votes
2answers
373 views

What does Scale mean in the reference of Desktop GIS or WebGIS?

I'm having trouble understanding the meaning of the concept of scale when it comes to maps on screen, i.e. either in a Desktop GIS or in a WebMap. When it comes to paper maps, the idea is very clear. ...
5
votes
1answer
2k views

How to calculate the bounding box by a given center and scale in Android?

Given these conditions: a scale like 1:50000 the center of the viewport is 100°E, 20°N the size of the viewport is 400x600 How can I calculate the bounding box of the viewport? Update after ...
5
votes
1answer
280 views

Georeferencing a jpeg in QGIS but the scale is way off

I've gone through the really helpful walk-through(s) of how to georeference a jpeg in order to make it a layer, but after inputting the coordinates (either by typing in actual coordinates or clicking ...
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 ...
5
votes
2answers
368 views

Can you print cross-hatch area fills like they appear on screen?

I'm trying to use a cross-hatch symbol on polygons in QGIS. When displayed on screen, they look just fine - both in the map and in the composer. The problem is when they are rendered to an image ...
4
votes
2answers
5k views

Arcmap 10 feature with undefined coordinate system projects incorrectly when projecton is defined

I'm fairly new to GIS, and am slowly feeling my way through ArcMap 10. I have run across a problem defining the Geographic Coordinate System and projection for a feature (the feature currently has an ...
4
votes
2answers
106 views

“GIS” Mapping on Monument - Scaling

I have a Baroque tombstone for which I have to map the damage phenoma. Normally one can use a vector drawing programm but one has always two boundaries between the different polygons. Questions: Is it ...
4
votes
2answers
83 views

Measuring scale for small scale maps

A cartography question: you open an atlas and usually at the beginning of it there are some world maps showing various thematics. Let's say the world map uses Robinson projection and it says it has a ...
4
votes
1answer
296 views

how does arcmap calculate scalebar inside a WGS84 layout?

ArcMap lets you put a scalebar inside a layout referncing a WGS84 data frame. How is the scale calculated? Is it a "mean" scale? And, in case it's right, what "mean" scale could mean?
4
votes
1answer
293 views

Why do base and overlay only match at scale 1:1000 and 1:2000?

We are using GEOSERVER 2.1.4 to overlay WMS on GoogleMaps V3 with Openlayers . The problem we have is at different zoom levels the scale of the WMS overlay is different from the scale of the base ...
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 ...
4
votes
1answer
428 views

How to automatically generate useful scales for data driven pages in ArcGIS desktop

I have been tasked with creating several hundred maps of properties that intersect a long pipeline. The maps will zoom to the part of the property which shows the intersection. The lengths of ...
4
votes
1answer
730 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 !
4
votes
1answer
748 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 ...
4
votes
1answer
356 views

How to use scale -rule based renderer in QGIS?

I wish to render a shapefile of builindings such that at scales below 1:5000, they have a border, and above 1:5000, they do not have a border. For this, I went into layer properties, selected ...
3
votes
1answer
294 views

Clarification of Map Scale

I need some clarification. I have a map the is set to the scale of 1:6000. In Settings>Project Properties, under the General tab I have the Layer Units set to feet. Therfore I assume that means the ...
3
votes
3answers
70 views

How do I create a map that is not to scale in QGIS?

I want to make a map that isn't to scale and I'm so used to being pedantic about CRS and scale that I don't know where to start. The map that I need to make is a simple guide for people to get to a ...
3
votes
1answer
283 views

How to get correct scale values?

The scale of my map is wrong, no matter what coordinate system I use in my project. The map and all objects show the correct coordinates but the scale of the map shows nonsense and the measurement ...
3
votes
1answer
901 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 ...
3
votes
1answer
356 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, ...
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 ...
3
votes
2answers
939 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 ...
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 ...
3
votes
2answers
583 views

Figuring out map scale when you know the spatial resolution of a Satellite Image?

I'm interested in figuring out how map scale and satellite pixel size (spatial resolution) are related. For example the TM or ETM+ has roughly 30m ground resolution, then, what could be the finest ...
3
votes
1answer
102 views

Sensitivity analysis for coarse scale GIS epidemiological model?

I am working on an epidemiological model with disease incidence rate as dependent variable and environmental factors as independent variable. Disease data is available at county scale whereas ...
3
votes
1answer
81 views

Is there a way to scale to 1:1 in QGIS Cloud?

Someone knows if with QGIS cloud Pro Plan, it's possible have a scale till 1:1. I use QGIS to draw small stuff on my gis (archaeological finds, as really small pottery's sherds) and I need a scale ...
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 ...
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 ...
3
votes
0answers
981 views

How to use Scale tool when Georeferencing Raster in ArcMap?

I'm georeferencing a bunch of maps in ArcMap 10.0. The Shift and Rotate commands are pretty easy to use, no problems there. But whenever I use the Scale command, the image completely changes ...
3
votes
2answers
332 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 ...
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 ...
2
votes
2answers
939 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 ...
2
votes
2answers
234 views

How do I know the vertical/horizontal units of my DEM? I'm creating a slope using gdaldem

I'm using gdaldem to create a slope map. I can apply a scale. The default is 1. The notes say: Ratio of vertical units to horizontal. If horizontal unit of source DEM is degrees (e.g WGS84 ...
2
votes
2answers
78 views

Scale and Z factor have no effect on hillshade analysis in QGIS

I used an SRTM DEM to create a hillshade in QGIS 2.2.0. However, the resultant hillshade seems to be vertically exaggerated. Also, changing the settings for scale and z-factor does not have any effect ...
2
votes
1answer
398 views

ArcGIS giving measured distances and the scalebar incorrectly

I am currently using ArcGIS 10.1 and am struggling to be able to measure distance or set a scale bar correctly. Its currently giving me absurd results orders of magnitudes to small (0.5m etc). All my ...
2
votes
1answer
320 views

importing coordinates via a csv file does not work

I tried to manually add point data via a CSV file to an empty project in QGIS 1.8.0. The points do show up all right with the correct coordinates, but already the scale is not correct (using the ...
2
votes
1answer
371 views

How to Determine to world map size in pixel given this data?

How to Determine the world map size in pixels given this data? Map size of a particular area say, for example: Makati city, Philippines with bounds: Top-Right: 121.0281, 14.56497 Bottom-Left: ...
2
votes
1answer
633 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 ...