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1

pseudocode for your problem would be: for point1 in csv: for point2 in csv: distance = haversine(point1, point2) where haversine is defined as (from e.g. http://gis.stackexchange.com/a/56589/15183) : def haversine(lon1, lat1, lon2, lat2): """ Calculate the great circle distance between two points on the earth (specified in decimal ...


0

If you have a one-band-dataset, it will be displayed as grayscale as default. You can change that to any kind of pseudocolour, depending on the software you use. To get real colours, you need either 3 band data with red-green-blue colour interpretation, or paletted colours.


1

As I am similarly not an expert in the field of color, I find that a good place to start is to use tools. They leverage the expertise of others who understand how colors work. If you have an image, website color scheme, page theme, or other source of colors, there are tools that will take an image and build a color palette based on the image. Other ...


1

Take a look at Color Brewer, a site that helps you to pick color schemes that are well-suited for communicating particular types of data. (I copied this description from this Wired article about Cindy Brewer, the creator of the site).


1

Just try to avoid green to red color ramps considering the color-blind population that may have difficulty interpreting your results. I am green/red color-blind and get frustrated when cartographers/GIS mapmakers use this option.


4

I've always been fond of a colour ramp that I use for visualizing flow accumulation (not that unlike your application) that transitions from black to blue to yellow to pale yellow. It does an excellent job of highlighting the high-value areas, gives good contrast within areas of low values and seems to be a bit warmer and less 'ghostly' than the ...


8

While Jacub is correct that a stream ordering technique is your best bet for being able to represent stream magnitude or discharge, since the position in the network is a surrogate for these two stream characteristics, I would argue that you want to avoid using Horton-Strahler stream order for this purpose. It is seriously deficient in these applications, ...


9

You can classify the streams using, among others, the Strahler Stream Ordering method. In the Strahler method, all links without any tributaries are assigned an order of 1 and are referred to as first order. The stream order increases when streams of the same order intersect. Therefore, the intersection of two first-order links will create a ...


1

You could try here. They seem to have a lot of shape files that might fit your description. Though the European dataset is in 30 year increments. Your best bet is probably going to have to be recreate it. Wikipedia has some WWI maps in PNG format. As others have mentioned, there are plenty of sites with historical raster maps that you could digitize.


1

Geoserver labels polygons,by default at the determined centroid of the polygon. You can try the Geoserver Extension PolygonAlign to allow Geoserver to try different orientations for the label to get it to fit .. GeoServer normally tries to place labels horizontally within a polygon, and gives up if the label position is busy or if the label does not fit ...


24

The location on the opposite side of the earth from your point is called your antipode or antipodal location. If you want to produce an antipodes map on your own there is a simple relation to consider: Your antipodal location by lat-long will be identical to your location, except with the direction reversed. For example, the latitude of the antipode of 40° ...


1

Google maps engine is quite handy for collaborative projects. Map object creation tools are easy to use for non-expert users.


0

Have you considered using geojson.io? It let's you collaboratively draw lines, points and also annotate them. This can be shared and embedded easily as well.


0

What you are looking for is to calculate points along a path starting at a specific lat/lon and bearing. You will want to pick an distance increment (e.g., 100 miles) to incremently plot points following the bearing across the globe. This stackoverflow answer gives such a formula using the Great Circle method for approximately the spherical of the globe: ...


0

I think the formula you are looking for is the haversine formula. See the Destination point given distance and bearing from start point section. Here's an R implementation to add to those given on the site: # Q: From London, what is 500 kilometres away in the heading of 110 degrees # London coordinates earthR <- 6371 # km olat <- 51.5073509 / 180 * ...


0

There is a distmap() function in spatstat package that creates a pixel image of the distance to the points. At the provided link you will find a great tutorial for this package (including distmap() example).


1

I had the same problem. The solution I found was to go into Data Frame Properties click the Coordinate System tab and then double-click on the projection you are using to bring up the Projected Coordinate System Properties window and change the Linear Unit (it's a drop down near the middle) to feet or yards or whatever unit you want. It will still be greyed ...


6

The Map has mostly remarks in French, so I would suggest to use a French coordinate system, and not Everest (who was British). The French used coordinate systems with a prime meridian based at Paris, so EPSG:4821 Voirol 1879 (Paris) is a good start-off. With that, the 100° meridian is hitting the Malaysian coast near Kota Baru, as in your map: You can ...


2

To begin with I would recommend you read this tutorial on georeferencing in QGIS http://docs.qgis.org/2.2/en/docs/training_manual/forestry/map_georeferencing.html Yes you can georeference this map. I would recommend you use a good quality flat scan of the map if possible. Avoid a crease running through the image. Accurate georeferencing depends on the ...


1

Esri world imagery layer is already a mosaic "in the cloud". I do not think you can download it and use it locally. You would also need a very large storage space if this was possible.


0

Hi scud42 thanks for your valuable thought. Here is my code and still its not working. I am sure I am missing something, so any thoughts on the matter would be appreciated. var polylineHighlight = new google.maps.Polyline(); if (GLOBAL_CARTODB_LAYER_ON != null) { return; } cartodb.createLayer(map, { user_name: 'user-name', type: 'cartodb', ...


2

One of the things you can do is request the geometry from cartoDB as in a geoJSON format as part of your SQL query: SELECT *,ST_ASGEOJSON(the_geom) AS geometry FROM your_table Google can take the geoJSON and convert it to polylines and polygons each time you mouse over a feature. Here's an example I've done with a polyline. You could do the same thing ...


1

The reprojection might fail for points that are located at the backside of the globe. Best solution is to clip the data to the visible hemisphere. I have given some advice on that here: Where did the polygons go after projecting a map in QGIS? and in the questions in the Linked section of that topic.


5

Here is a method using arcpy geometry objects. The script creates a rotated hull rectangle around each polygon, splits it into plots, and clips the plots to the original polygon. As Aaron mentions, you could likely achieve this with the fishnet tool, but I could not figure out how to (in Step #2) "use logic to find the ordinal coords" for rotated polygons. ...


2

A search with Google threw up these pages... http://blogs.esri.com/esri/arcgis/2011/09/06/creating-radial-flow-maps-with-arcgis/ http://blogs.esri.com/esri/apl/2012/09/12/generating-distributive-flow-maps-with-arcgis/ Someone has even created a tool that flows around country boundaries. ...


1

If you know how to use javascript and d3, then the spatialsankey d3 plugin might help. Here is an example application that does something similar to what you ask, though only to show flows in one direction.



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