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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2
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2answers
6k 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
432 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
2answers
1k 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
481 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
44 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 ...
2
votes
2answers
107 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
3answers
711 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 ...
2
votes
1answer
402 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 ...
2
votes
1answer
702 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
62 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
256 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
154 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
264 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
449 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
217 views

How to get a GML overlay on Google Maps?

Anyone know how to get a GML file to show as an overlay on Google Maps? To be honest I don't know my GML from my KML, or my ETRS89 from my WGS84, as this topic is completely new to me. A bit of ...
2
votes
0answers
46 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
68 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
44 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
471 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
319 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
113 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
vote
1answer
717 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
3answers
48 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
39 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
623 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 ...
1
vote
2answers
74 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. ...
1
vote
1answer
421 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
560 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 ...
1
vote
1answer
41 views

Loop to check multiple polygons overlap in r

I have a set of polygons (available here: http://ulozto.cz/x39ELbFt/polygons-zip) created in QGis and processed in R. I would like to know if they are overlapping or not, and if yes, where is the ...
1
vote
1answer
51 views

kml/kmz files not loading by google maps anymore

Until a few months ago this worked: https://maps.google.com/maps?q=http://www.jcea.es/pics/italia2015/italia2015.kmz It is NOT working anymore. I know that I can login in Google maps, create a ...
1
vote
2answers
76 views

Performing unweighted overlay on multiple raster layers

Is there a simple process in ArcMap v10.2 that will allow me to overlay three raster images, whereby any obscured pixels will be deleted in the output file? I do not want to retain the values of any ...
1
vote
1answer
106 views

Intersect Multiple Layers

I have thirteen polygon layers showing species at risk ranges - I have a standard arc GIS desktop license, allowing only two inputs to the intersect/union tool at one time. I need to create a "hot ...
1
vote
1answer
112 views

Erasing overlay geometry with in the feature class..!

What is the best practice for erasing overlay geometry? My scenario is: I have a polygon layer with 1000 features. i need to create a tool from model builder that select polygons with user defined ...
1
vote
1answer
67 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
vote
1answer
77 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 ...
1
vote
2answers
2k 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 ...
1
vote
2answers
885 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 ...
1
vote
1answer
167 views

How to display Lidar Data in ee0 (Interchange File) on Maps

Hi I have Lidar data in ee0 files (interchange files). Can i ovaerlay them on some maps like say Bing Maps or Geoserver with Open Layers? If yes whats the right way of doing it? Thanks
1
vote
1answer
296 views

Is Tile same as Layer?

Is there difference between a tile server or a layer server? Can I load tile in ArcGIS control in WPF from some other source? Can I host my own layer server? Or is there any such thing as layer ...
1
vote
1answer
96 views

Overlay analysis of two raster by attribute?

I have two rasters (one showing land use and the other showing soil texture). I'd like to find the areas where there is a specific land use on a specific soil texture. Is there a way to overlay two ...
1
vote
1answer
55 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 ...
1
vote
1answer
1k views

How to open overlay content from leaflet popup

Hi! I am currently working on an interactive leaflet map. I managed to display markers from a database via php (create an array). Now I want users to create markers with a click on the map. To add a ...
1
vote
1answer
231 views

Testing point in polygon overlay performance of Intersect, Spatial Join and Near in ArcGIS for Desktop?

In answers and comments to Select points within a polygon and update attributes I think it is being suggested that Spatial Join (Analysis) and/or Near (Analysis) may be faster than Intersect ...
1
vote
1answer
71 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 ...
1
vote
1answer
155 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 ...
1
vote
2answers
388 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. ...
1
vote
2answers
88 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 ...
1
vote
2answers
582 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 ...
1
vote
1answer
77 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 ...
1
vote
2answers
490 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 ...