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56

I found this response - written by a Google employee - this would probably be the most accurate one: This won't be accurate, because the resolution of a map with the mercator projection (like Google maps) is dependent on the latitude. It's possible to calculate using this formula: metersPerPx = 156543.03392 * Math.cos(latLng.lat() * Math.PI / 180) / Math....


20

Assuming you are talking about a map of the world in Mercator Projection, Something like this: Then, You should know that not all pixels will represent the same area. There is a large amount of distortion as you move towards the poles, the area represented by each pixel will decrease. Tissot's indicatrices show a good visual representation of the ...


19

Yes, it is possible. What you need is rule-based Styling with a scale rule as shown in the image (sorry for german layout) It looks like this when you zoom in and out : keep in mind, that when you zoom out of the defined zoom levels, the layer won't be shown. EDIT: To have different styles within a category you can refine the rules by right-clicking on a ...


15

I don't think there's an option yet which allows you to put the units below the scalebar. An alternative could be to: Modify your current scalebar and set its Font colour to match the background colour: Item Properties > Fonts and colours > Font colour Copy your scalebar and paste it directly below your original scalebar. Then set its Font colour to ...


13

Straightforward authoritative correct answer: 591657550.500000 / 2^(level-1) it gives you the table above, entering the zoom level. Try it live on jsfiddle.net Because the question is only for Google MAPS, not EARTH, the OP doesn't care about 3D geometry. Google maps are ALREADY flattened so 1 pixel is always the same distance (in DEGREES, which is what ...


13

You can get the current zoom level using getZoom(). Assuming that you're using the tile layer system as used by Google Maps, Bing, Open Street Map and Esri, you can use that to infer the scale - see What ratio scales do Google Maps zoom levels correspond to? If you're not using that tile system, you may need to find another way to infer the scale from the ...


12

@Gerardo's answer is only correct at the equator. The gdaldem doc notes those scale values are for "LatLong projections near the equator" To calculate the scale or Z factor (inverse of scale) at other latitudes for a dem with vertical units in metres, you can use the following equations: s=111320*cos(latitude*pi/180) z=1/(111320*cos(latitude*pi/180)) ...


12

You need to use Rule based style to set the scale for primary, secondary and tertiary network, as you can see below (but with different data): You can double-click each styled label to get more details:


11

As the scale is a ratio, it doesn't have units itself. You can measure whatever you like on the map - one inch, one foot, one double-decker bus - and it will represent 6000 of the same unit in reality. To give the scale in mixed units, you just have to know what 6000 inches are in feet - OnlineConversion tells me it's 500 feet - so you'd have 1 inch = 500 ...


10

EPSG:3857 doesn't conserve distances so this will depend on where on the earth you are mapping - I think the scale is calculated at the Equator. The easiest fix for this is to switch to an equidistant projection like: EPSG:102014 or other depending on your region of interest.


9

Ok, with some initial issues cleared out the task is relatively simple. Scale, prepresented as f.ex 1:50000 means that one unit on the map corresponds to 50.000 units in the real world. For a paper map printed a scale of 1:50000 this means that 1 meter on the map corresponds to 50.000 meters in the real world, or to make it easier: 1 cm on the map ...


8

Radius @ Equator 6,378,137 meters exact (WGS-84) Circumference at Equator = 40,075,017 meters (2πr) Zoom level 24 uses 2 to the 32 power (4,294,967,296) pixels at circumference. Equatorial Circumference / 2 32 = .009330692 meters per pixel Unit at Latitude = (Cosine of Latitude) X (Unit at Equator) Zoom level doubles each increment. 1 foot (...


8

You achieve this by having multiple data frames Working with additional data frames Then setting a difference reference scale per data frame. While in many maps, you'll only need one data frame, you can add more data frames by clicking Insert > Data Frame on the main menu. You can remove a data frame by right-clicking the data frame name in the table of ...


8

If you want to increase the size of a feature, you can use the Scale tool in ArcMap. It's an Editor tool but it's not on the toolbar by default, you'll need to add it using the Customize option for toolbars. It can be found under the Editor category: You can scale up your features by a Scale Factor by selecting your features, activating the Scale tool, ...


7

Rasters don't really have a scale, they have a resolution, which in your case is 200m. You can calculate an appropriate viewing scale for a given raster resolution based on the ability to distinguish features. The ArcGIS Blog post On map scale and raster resolution discusses this: In 1987, Waldo Tobler, renowned analytical cartographer (now emeritus ...


7

Not at all. When you have some data that was digitized at 1:100,000, it excluded smaller features, which were smaller than the Minimum Mappable Area. For example, suppose you are dealing with topographic data.At 1:100,000 you would exclude large streams and trees.These features are visible at 1:24,000, and should be included in such a map. If you just ...


7

First, a note about map scales. A map scale represented as a unitless factor (e.g. 1:50000) means that a map unit represents X map units (e.g. a meter in the map = 50 km in reality). This kind of scale is simply impossible to achieve in web maps, as you cannot be sure of the physical screen size. Think about a laptop connected to a projector screen, having ...


7

I have to say that what you are requesting is complicated a little bit because you want the labeling to be visible at small scale clearly as well as at large scale (best fit). So, the idea here is how to place the point that can be visible at different scales. After several testing, I found that instead of creating several columns for each scale range and ...


6

You must set the Project CRS to a projected CRS, for example the UTM zone for your part of the world. Thats different to the layers CRS, which might remain in degrees. Measurement tool and scale bar look only at the project CRS, as long as on-the--fly-projection is enabled.


6

You have to decide whether you want to enter coordinates in lat/lon, or from a background map with a projected CRS (e.g. in metres). For the first choice, you have to set the target CRS to WGS84 (EPSG:4326), and don't mix up lat and long values. For the second choice, the target CRS must be set to the same CRS as the project CRS. This can be different from ...


6

In QGIS it's not called Reference Scale. You can make sure line thickness and font size are visually the same in the map canvas and the print composer (regardless of paper size and extent) if you size your font labels and line styles using Map Units instead of points, mm, etc... There is also the option to use non-map units, and in that case you can just ...


6

I have test it a bit and seems to work correct. Inspired from this var res = getResolutionFromScale(200000); alert(res); function getResolutionFromScale(scale){ var units = map.getView().getProjection().getUnits(); var dpi = 25.4 / 0.28; var mpu = ol.proj.METERS_PER_UNIT[units]; var resolution = scale/(mpu * 39.37 * dpi); return ...


6

A PDF file has a controlled page size that can be used by the reader app (Adobe Reader or similar) to output a set page size when printed. Image files such as TIFF, PNG, BMP etc., are not a page at all, they're a picture/photo. Their size is dependant on the resolution and dimensions of the image in pixels, not a set page size. While I believe you ...


6

Because of Pseudo Mercator? Pseudo Mercator is not a proper Coordinate System to measure areas. Depending where you are on Planet Earth, there can be huge differences in area-size compared to other coordinate systems that try to reduce distortion.


6

You can use QAD Plugin which has a scale option, and you can enter a scale factor to scale your feature. If you are familiar with AutoCAD, this plugin works almost same, and it is very powerful. For the QAD plugin to work properly, the features should be projected either in meter or foot. It does not work with geographic coordinates. Also, you should work ...


5

I was involved in a lot of similar work in the past but with stone decay on buildings. Here are some references on that work which you may find interesting (if a little old now): Ball, J; Young, M E (2000) “Mapping The Decay & Weathering Of Stone: A Technique For The Assessment Of Large Numbers Of Buildings”,in Choi, S and Suh, M (Eds.) Proceedings ...


5

If you want a 1:50K map displaying an area 30 miles wide then your map will need to be 0.0006 miles wide, or about three feet, or over 3600 pixels at 96 DPI (typical computer monitor). You need to explain to your client that you can show either a desired area or a desired scale but you can't do both at the same time because you generally cannot control the ...


5

DPI means dots per inch. For your scanned map it is better to use PPI (pixels per inch). 150 DPI = 150 PPI = 150 pixels per 1 inch = 150 pixels per 2.54 cm = 150 pixels per 0,0254 m So 1 pixel has the size of 0.0254 m / 150 = 0.00016933 m. The scale of our map is 1:150,000. The scale is the ratio of a distance on the map to the corresponding distance on ...


5

I have written this on Android and it works. Google map tiles are 256 device independent pixels. So this first line calculates a tile size in device dependent pixels. The second calculates the number of tiles at a given zoom level. The third calculates the size of a tile in meters at a given latitude for spherical projection. Then the final line will give ...


5

The projection that you use will distort the properties of your objects. You can select your projection to preserve the shape, the area OR the distances but not all at the same time. If you want a specific feature to be preserved, you need to select a projected coordinate system with this property (conformal for shape, equal-area for area or equidistant for ...


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