I am working on my masters thesis trying to determine habitat prefrences for wild turkeys. I have polygon shapefiles which represent areas that turkeys used during different breeding periods. These polygons are all circular and vary from 300m to 1500m radius.
I have data to be extracted in the form of polygon shapefiles that I need to extract for each of the above mentioned areas. For example, one of my habitat data shapefiles maps out areas that were burned. This is a polygon shapefile with 100% coverage. The shapefile has an attribute Y_N_U where Y= yes, N=no and U=unknown. For each of my used circles I need to extract how much area was burned, not burned, and is unknown (can be in actual meters squared or % of the area .
Thanks for the help.
I would use union tool and union all the layers together.
Use select by attribute to and delete the polygons except for your target area (habitat polys).
Use dissolve tool on the above layer and run it with the "Y_N_U" attribute and the FID field of the habitat poly selected.
Then create a new field such as "Area_sqmeter". Run calculate geometry on that field - choose square meter for the unit.
Use the select by attribute tool under the selection button on top.
After this select the area you want. Right click on layer's name in the table of contents. Go down to the "data" tab and when it expands, click on "extract data". Be sure to choose to extract what is selected and extract it to a new file geo database.
Then you can edit it from there at your heart's desire while the original is still there.
Related
I am looking for a way to create a geojson file from the distributions of the health sectors in my region which are different than any political division readily available on osm:
There are fantastic tools such as geojson.io to draw custom polygons but because of the complexity I would need a tool that allows me to overlay an image to use it as a template or that does this automatically. If this makes a difference, I may be able to extract the silhouette with any computer vision library but my problem of how to get from an image or shape to geojson still remains.
Which is the fastest way to approach this?
You can do this using QGIS with manual georeferencing in order to assign real-world coordinates to an image without geo-information. This is done by clicking points on a map that correspond to points on your image. Then once georeferenced you can export the file as a geojson.
Another solution is to find a shape file (maybe this is correct) and simply convert the .shp into a geojson.
I have a set of data points where each point is expressed as a lat/lng. Each of these points has a value associated with it that changes over time. I would like to produce a heatmap animation overlay on top of a map that reflects this change in value over time. Note: I am fine with producing a series of static "snapshots" and piecing them together frame-by-frame into an animation, so the heatmap library itself does not have to support animation.
My first attempt was to use the HeatMapLayer which is a part of the Google Maps visualization library. However as per the question Heatmap based on average weights and not on the number of data points, it would seem that this particular visualization library insists on weighing the density of points in determining what color to use surrounding a given point.
I am after a solution that only considers the value of the points rather than the density. To give an example, assume one wanted to visualize the ambient temperature of a city over time, but there were more thermometers installed in some parts of the city than others. You wouldn't want a small area with many thermometers installed to show up red just because there were many thermometers - you'd want it to show up red only if it was hot there.
Basically, I want a single color for each of my points that reflects the intensity of the point's value, and then a gradient spatial transition between any two point's colors. It doesn't have to be Google Maps - the key criteria is just i) must base colors off point values not point densities ii) must overlay on top of a map and iii) ideally has a programming abstraction that talks in terms of lat/lng's, rather than requiring manual conversion to e.g. Euclidean space.
global tempsYou can do this with multiple:
gmaps.symbol_layer
and then just layer them up:
fig_gmap.add_layer(red_markers)
fig_gmap.add_layer(yellow_markers)
fig_gmap.add_layer(green_markers)
fig_gmap.add_layer(blue_markers)
I haven't been able to successfully pass a value that gives me a good temp color for the heat maps, just always get some variation on the density thing, which is a one trick pony. It would be nice having a way to do this and animate the marker icon without java.
Maybe you should try heatmap.js. It has a plugin for Google Maps: http://www.patrick-wied.at/static/heatmapjs/plugin-gmaps-layer.html
This library uses datasets made of coordinates and values. I think it will behave the way you described.
I have this map
I managed to extract each country in different png file and I made this map by using AS3 code to place each country in its own place. It works properly but there is one thing I don't like and that is the quality of the images. You clearly see gaps between some countries and some borders are thicker than others. That is because I did the extraction with free hand.
Is there a way to get more clear boundaries with code and export the result in png file for each country?
Maybe using some map services like Google maps?
I would recommend you to use vector images instead; you can find some in the SVG format (easily convertible) on Wikipedia:
http://upload.wikimedia.org/wikipedia/commons/b/b3/Blank_map_of_Europe.svg
Each <path></path> node in the file refers to a country, where the id attribute contains the country code and the d attribute is the path in the SVG format.
Well I have run into a bit of a small problem and I am not sure how to approach this. I have this test map.
http://www.mesquiteweather.net/googlemap_poly.html
Which creates polygons based on data from this XML file.
http://www.mesquiteweather.net/xml/warnings.xml
It displays weather alerts/watches/warnings etc on the map from the data which makes the polygon that shows what area the alert is in and I have an array in another file that assigns the color. All that works great.
Here is my problem. The XML feed doesn't always display alerts with polygon cords that can be split to create latlng object to create the polygons, I will only get county names half the time so there may be alerts in the feed but they will never get displayed if there is no polygon cords. If you look at the feed for cap:polygon you'll see not all of them have it. Right above it though is areaDesc which is the county name. So is there an easy way to create a polygon base on the county name from that data and how?
I have been searching the web with no results. I did read about fusion tables but will that work and can I use that to draw the polygons based on the data from the feed then have fusion tables draw it out? I don't know, I am doing stuff with Google Maps I have never done before so I am out of my element and could use some guidance and assistance. Any suggestions or advice would be greatly welcomed so I can put this project to sleep.
-Thanks
You can use FusionTables to display a FusionTablesLayer with specific counties on it, and style those polygons dynamically (with up to 5 style rules).
FusionTable containing US counties
Selected counties
Example that displays the counties (using a FusionTablesLayer) on the map
Proof of concept, not sure this will be usable with this many counties.
Probably OK with a small number of counties (your original example)
Re,
I have this strange problem... one track refuses to show in Google Earth. It displays the distance, elevation, everything, but there are no visible track lines. Importing it into Google Maps works fine.
Basically, I have a file with over 350k points. When assembling it, I separated tracks by dates and am now trying to merge them together (manually, by editing the KML file). It appears that when I try to merge placemarks with thousands of coordinates, they stop displaying in Google Earth; as if there is a limit as to how many coordinates a placemark (linestring) can contain.
Here's the file: http://www.upl.co/upload/s4Co0Gc2Q
Thanks in advance.
You need to use the <tessellate> element on the linestring. This specifies whether to allow the LineString to follow the terrain. To enable tessellation, the altitude mode must be clampToGround or clampToSeaFloor. Very large LineStrings should enable tessellation so that they follow the curvature of the earth (otherwise, they may go underground and be hidden).
The other option is to use the <gx:altitudeOffset> element. This is A KML extension, in the Google extension namespace, that modifies how the altitude values are rendered. This offset allows you to move an entire LineString up or down as a unit without modifying all the individual coordinate values that make up the LineString . (Although the LineString is displayed using the altitude offset value, the original altitude values are preserved in the KML file.) Units are in meters.
Something like this should work.
<LineString id="ID">
<extrude>1</extrude>
<tessellate>1</tessellate>
<altitudeMode>clampToGround</altitudeMode>
<coordinates><!-- lon,lat[,alt] --></coordinates>
</LineString>
I have a LineString with about 96000 coordinates, and see the same effect that I can load the KML in google-earth, and see everything correct, except for the LineString (lines are not displayed), as if I had execeeded a certain limit.
The coordinates do not have an altitude. I tried with and without tesselation and alitudeMode clampToGround.
Solution for me was to split the LineString up with a MultiGeometry, splitting it in half was sufficient (each LineString now has less than 64000k coordinates).