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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3
votes
1answer
2k 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 ...
3
votes
2answers
4k 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 ...
3
votes
1answer
732 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 ...
3
votes
1answer
52 views

How do I edit multiple features at one time?

In my case, there are about 30 overlaid features. How do I select all and edit them at one time? I want to reshape the features, mainly using the node tool to reshape a straight line into a (fake) ...
2
votes
2answers
192 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. ...
2
votes
3answers
2k views

How to find most common classification within buffers?

I have a point shapefile that identifies the location of incinerators in England and an output area classification shapefile. I have created a buffer for all the points in the shapefile because i ...
2
votes
2answers
72 views

Selection on Overlapping Polygons

I have converted a CAD file to GIS format using GIS (from .dgn to .shp)... In one layer I have polygons in which a smaller one is on top of the larger polygon. I can see both polygons however when I ...
2
votes
1answer
1k views

Apportion Neighborhood Information to Census Tracts

I have a shapefile of census tracts and another shapefile of "neighborhoods" with values that I need to have joined to the census tracts. I know I need to apportion the area of the neighborhood ...
2
votes
3answers
11k 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
2answers
7k 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 ...
2
votes
2answers
481 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 ...
2
votes
1answer
54 views

Aggregating up spatial information

At present I have a dataset which is broken down by Electoral Divisions (circa 3,500). However, due to issues with some of my variables I need to choose a larger spatial unit - Local Electoral Area (...
2
votes
4answers
1k 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 select-by-...
2
votes
2answers
2k views

Image display/scaling in OpenLayers vs Google Maps

When I plot an image on OpenLayers, it looks like that image is stretched a little bit as compared to Google Maps. I was wondering if it is normal or there is something wrong with my code. ...
2
votes
1answer
547 views

polygon map overlay algorithm

There are many algorithms for binary map overlay operation in vector data format which take two layers of map and produce resultant layer i.e overlaid layer as output. I am wondering whether there are ...
2
votes
1answer
186 views

Display LiDAR data in E00 (interchange file) on maps

I have Lidar data in E00 files (interchange files). Can I overlay them on some maps like say Bing maps or Geoserver with OpenLayers? If yes, what is the right way of doing it?
2
votes
1answer
34 views

Summarising an attribute from point layer in polygons with FME

I have a number of polygon feature sets and a point layer containing an attribute with population count. I want to summarise the population attribute for all points within each polygon feature set ...
2
votes
1answer
80 views

Calculating total area overlapping specific raster DEM color interval whose boundaries are confined by another vector?

I know this sounds quite difficult, but maybe it isn't for you or at least it shouldn't if I explain it correctly. (I'm using QGIS 2.14) I'd like to know to calculate total area overlapping a ...
2
votes
1answer
54 views

PostGIS function ST_SymDifference between two segment groups produces unexpected results

I try to calculate the symmetric difference for a set of segment groups A and B with precision of 1E-5 (ST_SnapedToGrid(geom,1E-5). I've formulated the an ideal test case for a H based shape segment ...
2
votes
1answer
67 views

Overlay a shape into a gridded shape and determine the percentage of each cell that are overlapped

I would like to know how I can overlay a shapefile (A) into another gridded shapefile (B) and extract the information about which shapefile (A) polygons falls in each cells (B). And, more specifically,...
2
votes
2answers
196 views

How to add updated tiles to ArcGIS mosaic

I have several hundred aerial imagery raster tiles (in ecw format) that I have loaded into a mosaic dataset. I would now like to 'replace' or 'overlay' an older aerial imagery layer with this dataset. ...
2
votes
1answer
90 views

Combining several rasters before r.surf.contour?

I have been trying to generate an elevation model from contour lines using first v.to.rast.attr and then r.surf.contour. Generally, it works pretty well, execpt for one issue. My data contains a lot ...
2
votes
1answer
505 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 OpenLayers.Control....
2
votes
1answer
912 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 (...
2
votes
1answer
415 views

Loading texts with shapefile in ArcMap

I am currently trying to load different shapefiles in ArcObjects programmatically. Currently I can load lines, polylines, polygons and ellipses (even though that's just a fancy polygon as far as ...
2
votes
1answer
68 views

How to convert Geodatabase to open standards to process it further?

I have a ESRI file in geodatabase format (v9.3). I intend to use this in a non-commercial application. I think I will have to convert it into a open standard since I am confused if ArcGIS online would ...
2
votes
1answer
64 views

Question regarding area overlap

I'm using land use data, and report the proportion of each sub-catchment that is used for “Grazing Modified Pastures” and “Irrigated Modified Pastures”. I'm essentially focused on these two layers, ...
2
votes
1answer
428 views

Import data, analyze spatially, and export list of points using Google Earth

I am trying to: import data into Google Earth from an outside data source. Then overlay a map and isolate which datapoints fall into that area. I would like to then export a list of the data points ...
2
votes
1answer
195 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 ...
2
votes
1answer
299 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 ...
2
votes
1answer
527 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 ...
2
votes
1answer
36 views

How to display data at diffrent depths in ArcScene

I am looking for a way to display data at different depths in ArcScene. I have a bathymetry layer which displays fine, and I want to overlay oil platforms in 3D over the bathymetry to show where ...
2
votes
1answer
34 views

How to show overlay in layout legend [closed]

I am displaying three different layers on a map, essentially three separate habitat types. Each have their own colour. In cases, 2 or 3 of the layers overlap in part (essentially showing where ...
2
votes
1answer
518 views

OpenLayers3: How to show a KML layer with the export to png Button

so... I have this script: <script> //Script1: Script de criação do mapa. var map = new ol.Map({ layers: [ new ol.layer.Tile({ ...
2
votes
0answers
53 views

How I can create a raster and have the same overlay as another raster in QGIS 2.4?

I have made a graphical model in QGIS 2.4. I have to create a raster equation to rasterize a polygon shapefile. I want to rasterize my shapefile and I want to ensure that this new raster will ...
2
votes
1answer
91 views

strange banding in output raster after weighted overlay

I am trying to conduct a weighted overlay. I have two rasters, one is a continuous slope raster that I reclassified to have 6 classes (8bit signed integer), and one is an elevation raster that I also ...
2
votes
0answers
48 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 ...
2
votes
0answers
263 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 ...
2
votes
0answers
473 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. ...
2
votes
0answers
545 views

Creating a sidewalk map for a walkability survey

If I wanted to do my own walkability survey of my city, what tools could I use? I have map data from OpenStreetMap, but I have to consider that streets have two sides (which aren't always accessible ...
1
vote
1answer
39 views

Overlaying two vector shapefiles on a basemap results in a misalignment

I have been trying to overlay two shapefiles of the Harare Zimbabwe streetmap one with centerlines and the other digitized as polygons. the challenge i am facing is that the two overlay but not on the ...
1
vote
1answer
682 views

Identity tool does not work as expected

I have two shapefiles. Shapefile A has five attributes and shapefile B has 20 attributes. I use the Identity tool to determine, what of shapefile A lies in shapefile B. This is how both attribute ...
1
vote
2answers
194 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 X%...
1
vote
1answer
852 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?", { ...
1
vote
1answer
49 views

Determine the range of values in one raster associated with certain values in another raster

I have two rasters, one with thematic data, and the other with continuous data (floats). I am trying to calculate/determine the the range of float values associated with the different classes in my ...
1
vote
2answers
58 views

How to overlay subset of one data set onto another

I have two data sets: one for Thurston County, Washington and one for all of Washington state. I created a map of hydrology features in Thurston County, and now I want to take the data from the ...
1
vote
3answers
279 views

Creating a new raster layer based on mean of other raster layers, ignoring NA values in R

I am trying to create a new raster layer that is made up of the mean values from 7 other raster layers. I get results using overlay function mean: mean <- overlay(2000, 2001, 2002, 2003, 2004, ...
1
vote
1answer
91 views

Calculating area of residential area wihin multiple ring buffer in ArcMap?

I need to calculate the size of residential area within 0-250m, 250-500m and 500-750m of a bus stop. I have made a multiple ring buffer around the bus stops. And I have a shapefile of the residential ...
1
vote
1answer
257 views

Calculating coverage of vector polygon over other polygons?

I have a shapefile file that contains a LiDAR footprint and I'm trying to figure out how much a county is covered by the LiDAR footprint. Two separate shapefiles. The attribute table for the county ...
1
vote
2answers
90 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. ...