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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0
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2answers
209 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 ...
1
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0answers
50 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
37 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
vote
1answer
136 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
120 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
vote
1answer
75 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
53 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
326 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
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1answer
58 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 ...
4
votes
4answers
2k 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
vote
0answers
106 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
312 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
279 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
119 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
731 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
437 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
280 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
71 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
230 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 ...
5
votes
1answer
456 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
1k 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
308 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
551 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
230 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
388 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
5k 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
215 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 ...
0
votes
1answer
259 views

Does a polygon in a layer intersect with another polygon in the same layer [closed]

I am a CS major with little experience in GIS. I am working on vector polygon overlay. Looking at GML and shapefile data, I realized that a map is made up of a large number of polygons. Does a polygon ...
3
votes
1answer
1k views

UK region overlay on map

I'm hoping to overlay UK regions (East Midlands, Wales, London etc) on a Google Map. Ideally the regions could be coloured, opaque and have some form of label. There is no hover / interaction ...
0
votes
1answer
143 views

overlay a county shapefiles for 2 different years [duplicate]

Possible Duplicate: overlay county shapefiles for 2 different years 2 down vote favorite I have county-level shapefile for South Caroline in 1880 and one for 1940. I would like to overlay ...
3
votes
2answers
239 views

calculate coastline at risk

I have an idea of what I want to do but I don't know yet what tools will bring me there. I have administrative boundaries in one layer and coastline in another layer. The coastline is categorized in ...
2
votes
1answer
358 views

Technique using GDAL to overlay / fit one PNG map to directly overlay on another?

I have one .PNG basemap with known North edge of Latitude = 52.48, a South edge of Latitude = 21.94, an east edge of Longitude = -61.87 and a west edge of Longitude = -129.37. And I have another PNG ...
4
votes
3answers
440 views

Can I have Points, Lines and Polygon features in one QGIS layer?

I have a situation where planning is done on a "base map" consisting of rivers, contours, roads etc. There is a need to create a "overlay(s)" over the "base map" consisting of drawings, that could be ...
1
vote
1answer
233 views

Summarize polygon area using another polygon

I have a shapefile representing public/private lands in Montana. This is a multipart shapefile where I've simplified attributes so that #1==private and #0==public. Next I have a shapefile of ...
2
votes
2answers
4k views

How do I overlay a KML on leaflet 0.4.4

I am using Leaflet 0.4.4, I have a KML I would like to overlay on the map, how do I go about doing this? Edit: I am already aware of https://github.com/CloudMade/Leaflet/issues/14, which directs ...
1
vote
0answers
454 views

Zipcode overlay on OSM

I have to display an overlay with different colors depending on the zipcode in Europe. Can I get this information from OSM shapefile ? If yes, how exaclty ? Is there a tutorial somewhere ? Thanks
3
votes
2answers
2k views

Load layers only when zoom level is reached

I'm trying to load different layers based on the user zoom level with OpenLayers. I've seen some similar questions in here, but they load the layer and then hide/show it based on the zoom level. I ...
1
vote
2answers
1k views

OpenLayers WMS disappears when including OpenStreetMap

Setup: ArcSDE 9.3.2 Oracle 11g GeoServer 2.1.4 OpenLayers (latest build) OpenStreetMap InternetExplorer 7.0/ Google Chrome EDIT: I have updated information just below the screen shots ...
6
votes
1answer
520 views

overlay county shapefiles for 2 different years

I have county-level shapefile for South Caroline in 1880 and one for 1940. I would like to overlay these two files so that they do the union and indicate the percentage of the land in 1880 that went ...
1
vote
1answer
274 views

How can I move diagrams?

Is there a way to locate diagrams and move them wherever you want in QGIS 1.7.4/ 1.8.0? I created a pie chart under the tab "diagram". I can mark those diagrams with a green box and move them via the ...
1
vote
1answer
546 views

Can't display overlay

I am trying to add a WMS radar overlay to my map but it won't seem to gather it. noaaRdr = new OpenLayers.Layer.WMS("Latest Radar", "http://nowcoast.noaa.gov/wms/com.esri.wms.Esrimap/obs?", { ...
3
votes
1answer
428 views

Area overlay of census on Zip Code

I have census block data polygons. I want to overlay them over Zip Codes (larger polygons) in order to estimate the population in the Zip Codes. Or overlay buffers around toxic waste sites over census ...
2
votes
2answers
379 views

count features in polygon shapefile A that fall within each feature of polygon shapefile B

I have two polygon shapefiles, each of which contain multiple (possibly overlapping) polygons. Is there some way, using GRASS, to calculate the number of polygons belonging to shapefile A that fall ...
3
votes
1answer
835 views

Why does my WMS layer overlap the Google Maps v3 logo?

I'm using Google Maps v3 as a base layer and on top of that I create an overlay pointing to my WMS (streets and avenues). A few months ago all works fine, my WMS layer was not overlapping the Google ...
1
vote
1answer
442 views

Merge two maps with OR operation in GRASS

I have two vector maps. The two maps cover the same area but are split up into polygons differently (i.e. if you were to imagine one map placed above the other, the lines defining the polygons would ...
3
votes
2answers
734 views

Clip depth contour with spatial polygon

I need to somehow combine my Spatialpolygons with my depth contour, but not sure how do to so. Maybe create a SpatialPolygonsDataframe? This is what I've done so far: > class(subarea0) #This is ...
5
votes
1answer
1k views

How to rasterize SpatialPolygons in R?

I'm trying to extract the bathymetry values of my area of interest from a world bathymetry raster layer using the 'rasterize' function in the {sp} package. *Edits: I found the 'extract' function ...
1
vote
2answers
650 views

QGIS layers no longer overlay when Enable 'on the fly' CRS transformation is on

My QGIS project has two layers - one retrieved from GADM (administrative boundaries of Guinea Bissau) and another one of the villages collected in the field using GPS Decimal Degrees - D.ddddd. If I ...
2
votes
1answer
560 views

Select vectors overlapping a raster

I have a raster layer with travel times from a specified point in my city's downtown. What I'd like to do is select all of the census blocks that lie at least partially within 45 minutes of downtown ...
1
vote
1answer
940 views

Creating a Google Maps GroundOverlay with UTM NAD83 data

Edit4: The solution I posted from Jenner at VBforums was, obviously, in VB, and I used an online converter to port it to C#. Something was lost in translations, and that's why it was 10 miles off. ...