A spatial operation in which two or more maps or layers registered to a common coordinate system are superimposed, either digitally or on a transparent material, for the purpose of showing the relationships between features that occupy the same geographic space.

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1answer
91 views

Overlap or intersect two choropleth [closed]

I have two choropleth of the same area but with different concentration data and I need to overlap them. My aim is to highlight the areas of intersection between the points with the highest ...
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1answer
131 views

Weighted Overlay with “nodata” cells

I´m currently conducting a suitability analysis with the weighted overlay function. One relevant criteria is the proximity to highways. If the wind turbine is located up to 300 m away from the ...
1
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0answers
136 views

Problem with polygon overlay in raster stats using gdal

I am using the raster_stats module in python to calculate the mean carbon value for different sets of polygons. Here is the code that I am using: africa_sat = ...
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0answers
19 views

Openlayers and Geoserver: Google Maps and WMS Overlay [duplicate]

I'm trying to overlay a WMS layer in Google Maps. My coat is already projected in EPSG: 3857 and has prj file. I used the following command in postgis to confirm: the result EPSG:3857 SELECT ...
0
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1answer
264 views

I can not override my WMS layer in Google Maps as a base

I can not override my WMS layer in Google Maps as a base: I have a WMS layer in geoserver am using openlayers to show them. Calling only works WMS layer:   see my code, I am using using the bounds ...
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0answers
52 views

Calculating Percent Overlap Between Distribution Maps

Hello there, I am currently trying to calculate the percent overlap (basically the total amount of overlap where these two species come into contact) between Lithobates catesbeiana (first image) ...
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1answer
59 views

Extract information of a raster overlayed on another raster with a lower resolution directly in python

I have two aligned rasters with the same extent, one has a resolution of 5 meters and the other of 125 meters. I would like to place the 5 meter one over the 125 meter one and assign to these smaller ...
1
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1answer
127 views

How to combine Boolean and Fuzzy logic?

So I have a set of 5 Fuzzy Memberships and a polygon feature class, to which I already added a yes/no field. For the final map, I need to combine/overlay all Fuzzy Memberships and the rasterized ...
0
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1answer
29 views

How to select the identities of a layer present just in one identity of another layer

I'm a student approaching to QGIS 2.0.1-Dufour. My goal is to know how much identities of a layer are present just in one identity of another layer. I tried both with the tools "spatial query" and ...
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1answer
126 views

QGIS 2.0: move basemap by hand in order to achieve overlaying with a point layer

I am an environmental engineer and the aim of my QGIS 2.0 project is to visualize the results of a sewage water system inspection. In a first step I included the hoppers from a csv file and added a ...
1
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2answers
70 views

Historical maps as cylindrical projections

Objective: I want to overlay old, historical maps on top of Google Maps. According to Wikipedia, Google Maps uses a variant of the Mercator projection, a close relative of cylindrical projections. ...
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0answers
175 views

QGIS plug-in equivalent of ArcGIS's Spatial Analyst Tools -> Overlay/ Weighted Overlay

Specifically I have 12 .bil raster files that show monthly global mean minimum temperature. I file for each month. I want to combine these to create an ANNUAL global mean minimum temperature. In Arc I ...
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2answers
214 views

Replace google map MARKER with HTML element

I want to add a custom HTML element (that can become transparent dynamically) instead of a marker. Basically my html object would be a cirle (or rounded pin) with a picture of users in the middle. ...
0
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0answers
31 views

Overlapping of two layers in MySQL spacial extensions

I have been into GIS for almost a week now. Right now, I am learning MySQL spacial extensions. I have a question regarding the functions MySQL provides: I have a table that consists of LineString, ...
0
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0answers
208 views

How to import AutoCAD .dwg files as overlay on map in Drupal (using OpenLayers)

I am using OpenLayers on my Drupal site. The request is to import AutoCAD .dwg files as an overlay to maps on the site. Is this possible and how? I found the OpenLayers Editor for Drupal, am I on the ...
0
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1answer
50 views

Calculate best area with overlaying multiple layers buffer shapes

I am using QGis and I have a set of 20 layers with buffers. I'm interested in where they overlap most and I want to create a single layer that shows which are the places where they overlap most and ...
3
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1answer
382 views

remove land area from marine region polygons

In my pursuit to merge multiple polygons for the purpose of calculating the surface area of marine species distributions, using shapefiles from Marineregions, I am now trying to remove potential land ...
2
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3answers
483 views

Produce a list of polygons that a line crosses

I have a polyline feature class and a polygon feature class. What I want to do is add a field to the lines that lists all polygons that touch the line. This is effectively performing a ...
1
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2answers
92 views

What is the most efficient method to delete points?

I have a script that takes a point featureclass (FC) through the following workflow: Select points that lie within individual polygons From the selected points within each polygon, randomly subset ...
1
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2answers
70 views

Why does my gpx layer go to the wrong spot even if they have the same CRS?

Help! I am a QGIS beginner with a big problem! I am trying to load a gpx file from Garmin into my map. The project CRS is WGS 84, and the incoming data is in CRS WGS 84. When I look at the bottom of ...
0
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1answer
354 views

How to calculate proportional data for a polygon by taking attributes from other polygon

I have a features class which has polygons in it. I also have a Block group level data for demographic variables like population. Now when I overlay the polygon on the block group level data to find ...
8
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3answers
585 views

Create interactive map with no server

I have managed to build a great web mapping application using tiles created from GeoWebCache and a custom gridset, but I now need to add an overlay to the base maps. The only interactivity I need is a ...
1
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2answers
519 views

OpenLayers: Strange Tiling Issue (Checkered, white and grey) when panning around map

So this strange tiling issue is only occuring when moving around the map. Some things to note: 1) You can see the markers, airplane icon, and flight paths. These are all overlays, where the actual ...
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2answers
409 views

“Identity” overlay in QGIS?

I have two polygon layers I'd like to overlay using QGIS or another open source tool. What I want as output is a polygon layer with the extent of one polygon, but with each polygon in that layer ...
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0answers
54 views

How to maintain polygon boundary location during overlay in ArcGIS

I am working with ArcGIS Desktop 10.1 (Advanced license). I am trying to overlay two polygon layers (buildings and landuse) via an Update overlay such that all building polygons are retained and the ...
2
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0answers
40 views

Layers with the same Geographic Coordinate system don't overlap [duplicate]

I am a GIS newbie. I'm having a problem that, from the looks of things on this website, is a fairly common problem. I have 3 layers, all in the same GCS that do not line up. I have read all the the ...
1
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1answer
172 views

kmz mismatch in the Google Maps API v3 and Google Earth

I have some kmz files(exported from ArcMap). They overlay perfect with the base maps of Google Earth, but when it applied to Google Maps API, they mismatch the base maps. Can anyone give me some ...
2
votes
1answer
142 views

Reproject gif.gz raster to WGS84 in QGIS

I am a steep learning curve into QGIS. I have a raster of global fire maps from the modis site: http://lance-modis.eosdis.nasa.gov/imagery/firemaps/firemap.2013221-2013230.8192x4096.gif.gz I would ...
1
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1answer
76 views

Counting and sum by two layers

I´ve got to layers, both polygons. Layer 1 consists of propertiers, where ID is individually names. Layer 2 consists of lakes. The query I want is: Total count of squaremeters of lakes for each ...
0
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0answers
78 views

Making a KML layer “always on”

Is there a KML tag or specification by which you can force a given layer (specifically, a screen overlay) to be "always on", in that there is no way for the user viewing the file to make that layer ...
1
vote
2answers
414 views

Transforming a Google Maps overlay to fit an Ordnance Survey projection

I am currently in the process of creating a map with some administrative boundaries on it. The base map I am using is an ordnance survey map 1:10000. I downloaded an administrative border as a .kml ...
1
vote
1answer
70 views

Why are attributes missing in overlay tab QGIS 1.8.0?

I want to add a diagram overlay onto a shapefile layer. When I look at the attribute table, all the correct columns are shown. However, when I open the layer property box, the attribute columns I want ...
6
votes
5answers
4k views

how to overlay a polygon over SpatialPointsDataFrame and preserving the SPDF data?

I have a SpatialPointsDataFrame with some additional data. I would like to extract those points inside a polygon and at the same time, preserve SPDF object and its corresponding data. So far I've ...
1
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0answers
152 views

GRASS v.overlay.or Error when trying to split a polygon with a line

I am using the Grass plugin in QGIS for Windows (1.8.0). I am trying to split a polygon with a line feature. I am using the v.overlay.or function within the QGIS Grass plugin. I have the line layer ...
3
votes
2answers
455 views

How to calculate the shared area between a raster and a shape file in ArcGIS 10?

I have a raster file with 5 classifications developed from habitat modelling algorithms. I'd like to know how much of 2 classes of the raster is covered by the network of protected areas (Shape file). ...
1
vote
2answers
421 views

Calc vs. Overlay for speeding up band math in R 'raster' package?

Regarding yesterday's question about how to speed up band math in the R 'raster' package, would it be the same to use overlay to calculate NDVI instead of calc? If that's not the case, what's the ...
2
votes
2answers
126 views

Identify parcels that have two types of land use

I have two polygon layers in a geodatabase. One layer is land parcels. The other layer is land use. I want to identify the six largest parcels that contain both "upland forests" and "wetlands" (i.e. ...
3
votes
1answer
950 views

ArcMap 10.1 Spatial Join: 'Contains' and 'Within' question

I have two polygon datasets: electoral districts and postal code areas. I'm performing a spatial join to see which postal code areas are completely within a district (the area can touch the borders, ...
3
votes
2answers
635 views

Overlay Vector Layer on Raster Layer

How can I overlay a Vector Layer on a Raster Layer and assign NoData Values on the Raster where the Vector Layer does not cover the Raster Layer? (preferable with ArcGIS)
3
votes
1answer
377 views

Find which grid cells contain a point

I have a dataframe with x,y coordinates. I've sampled 10 x,y coordinates from my dataframe: y <-c(24.637032,21.569813,21.687,19.677183,24.72438,21.433136,24.637032,22.21065,21.443762,25.273882) x ...
1
vote
1answer
73 views

Stamp out and transfer values from one overlayed vector layer to another

I have a vector layer with administrative boundaries and another vector layer with postal code boundaries, which are more precise/smaller entities/objects. I now want to transmit the values of one ...
5
votes
1answer
321 views

What tool do I need to have satellite background images to draw features of a postgis database?

What tool do I need to have satellite background images to draw features of a postgis database? I looked about Geomajas but seems very complex for what I'm trying to do. I have osm data imported in ...
6
votes
2answers
556 views

Generate tiles for google maps overlays

I am trying to show some information on Google Maps which would be in the form of translucent circle overlays. The problem is that some circles overlap, which results in increased opacity and blending ...
5
votes
2answers
2k views

Display Georeferenced Images on Android

I'm looking for an Android application (best would be Open Source), that can display georeferenced images on top of a map (Google, OSM, ...). By Georeferenced I mean that the images four corners are ...
1
vote
0answers
354 views

Raster Over Layer in Leaflet from GeoServer

I want to add a raster over layer onto the base layer and the raster layer is published by a Geoserver WMS. I set the raster layer's geographic coordinate system as the same as the cloudmate tiles. ...
0
votes
1answer
742 views

In leaflet does the addControl automatically handle events via the leaflet API?

I need to add additional overlay layers to be controlled by the controls within the leaflet map boundaries, but the code utilizes a leaflet-custom.js file. I am assuming it handles the event and ...
2
votes
1answer
324 views

How can I enable panning using Openlayers and a vector overlay with controls?

I am creating a map using the following code: map = new OpenLayers.Map({ div: "map" }); Then I load in a geojson polygon layer and add two controls var highlightCtrl = new ...
4
votes
1answer
485 views

Shapefile vs Arrays of coordinates to build Google Maps overlay?

I am very new to GIS, and my task is to overlay about 100 polygons on a map. I'm using Google Maps Javascript API v3. I think I can define all my polygons as sets of lat/long coordinates in my ...
2
votes
3answers
7k views

Can OpenStreetMap be used as a WMS service in MapServer?

I want to produce a png image that uses OpenStreetMap data and has a vector overlaid on the base data. I am able to produce the vector overlay from within Mapserver, but I have difficulty ...
2
votes
1answer
242 views

Overlay analysis of topographic data

I have a topographic map with Buildings, Roads, Hydro and land use as the prominent layers in polygon format. Also i have newly collected Building polygons of the same area in shape file format. Now i ...