${gcp[2]}, ${gcp[3]}

2e:null 2f:["$","title",null,{"children":"gdaltransform | Bert Spaan | Observable"}] 34:Tc64,function GDALCreateGCPTransformerEx(pasGCPList, nReqOrder, bReversed, bRefine, dfTolerance, nMinimumGcps) { // double *padfGeoX = nullptr; // double *padfGeoY = nullptr; // double *padfRasterX = nullptr; // double *padfRasterY = nullptr; // int *panStatus = nullptr; const nGCPCount = pasGCPList.length let nCRSresult = 0 let sPoints = new Control_Points() let x1_sum = 0 let y1_sum = 0 let x2_sum = 0 let y2_sum = 0 // memset( &sPoints, 0, sizeof(sPoints) ); if (nReqOrder == 0) { if (nGCPCount >= 10) { // for now we avoid 3rd order since it is unstable nReqOrder = 2 } else if (nGCPCount >= 6) { nReqOrder = 2 } else { nReqOrder = 1 } } const psInfo = new GCPTransformInfo() psInfo.bReversed = bReversed psInfo.nOrder = nReqOrder psInfo.bRefine = bRefine psInfo.dfTolerance = dfTolerance psInfo.nMinimumGcps = nMinimumGcps psInfo.nRefCount = 1 psInfo.pasGCPList = pasGCPList psInfo.nGCPCount = nGCPCount // memcpy( psInfo->sTI.abySignature, GDAL_GTI2_SIGNATURE, strlen(GDAL_GTI2_SIGNATURE) ); // psInfo->sTI.pszClassName = "GDALGCPTransformer"; // psInfo->sTI.pfnTransform = GDALGCPTransform; // psInfo->sTI.pfnCleanup = GDALDestroyGCPTransformer; // psInfo->sTI.pfnSerialize = GDALSerializeGCPTransformer; // psInfo->sTI.pfnCreateSimilar = GDALCreateSimilarGCPTransformer; /* -------------------------------------------------------------------- */ /* Compute the forward and reverse polynomials. */ /* -------------------------------------------------------------------- */ if (nGCPCount === 0) { throw new Error('NOT ENOUGH POINTS') } else if (bRefine) { throw new Error('remove_outliers not implemented') // nCRSresult = remove_outliers(psInfo); } else { /* -------------------------------------------------------------------- */ /* Allocate and initialize the working points list. */ /* -------------------------------------------------------------------- */ let padfGeoX = [] let padfGeoY = [] let padfRasterX = [] let padfRasterY = [] let panStatus = [] for (let iGCP = 0; iGCP < nGCPCount; iGCP++) { panStatus[iGCP] = 1 padfGeoX[iGCP] = pasGCPList[iGCP].dfGCPX padfGeoY[iGCP] = pasGCPList[iGCP].dfGCPY padfRasterX[iGCP] = pasGCPList[iGCP].dfGCPPixel padfRasterY[iGCP] = pasGCPList[iGCP].dfGCPLine x1_sum += pasGCPList[iGCP].dfGCPPixel y1_sum += pasGCPList[iGCP].dfGCPLine x2_sum += pasGCPList[iGCP].dfGCPX y2_sum += pasGCPList[iGCP].dfGCPY } psInfo.x1_mean = x1_sum / nGCPCount psInfo.y1_mean = y1_sum / nGCPCount psInfo.x2_mean = x2_sum / nGCPCount psInfo.y2_mean = y2_sum / nGCPCount sPoints.count = nGCPCount sPoints.e1 = padfRasterX; sPoints.n1 = padfRasterY sPoints.e2 = padfGeoX sPoints.n2 = padfGeoY sPoints.status = panStatus nCRSresult = CRS_compute_georef_equations(psInfo, sPoints, psInfo.adfToGeoX, psInfo.adfToGeoY, psInfo.adfFromGeoX, psInfo.adfFromGeoY, nReqOrder) } return psInfo }35:T5d1,function calcls (cp, m, x_mean, y_mean, a, b, E, N) { // C++ signature: // static int calcls ( // struct Control_Points *cp, // struct MATRIX *m, // double x_mean, // double y_mean, // double a[], // double b[], // double E[], /* EASTING COEFFICIENTS */ // double N[] /* NORTHING COEFFICIENTS */ // ) let numactive = 0 /* INITIALIZE THE UPPER HALF OF THE MATRIX AND THE TWO COLUMN VECTORS */ for (let i = 1; i <= m.n; i++) { for (let j = i; j <= m.n; j++) { m.setM(i, j, 0) } a[i-1] = b[i-1] = 0 } /* SUM THE UPPER HALF OF THE MATRIX AND THE COLUMN VECTORS ACCORDING TO THE LEAST SQUARES METHOD OF SOLVING OVER DETERMINED SYSTEMS */ for (let n = 0; n < cp.count; n++) { if (cp.status[n] > 0) { numactive++ for (let i = 1; i <= m.n; i++) { for (let j = i; j <= m.n; j++) { m.setM(i, j, m.getM(i, j) + term(i, cp.e1[n] - x_mean, cp.n1[n] - y_mean) * term(j, cp.e1[n] - x_mean, cp.n1[n] - y_mean)) } a[i-1] += cp.e2[n] * term(i, cp.e1[n] - x_mean, cp.n1[n] - y_mean) b[i-1] += cp.n2[n] * term(i, cp.e1[n] - x_mean, cp.n1[n] - y_mean) } } } if (numactive <= m.n) { throw new Error(ERRORS.MINTERR) } /* TRANSPOSE VALUES IN UPPER HALF OF M TO OTHER HALF */ for (let i = 2; i <= m.n; i++) { for (let j = 1; j < i; j++) { m.setM(i, j, m.getM(j, i)) } } return solvemat(m, a, b, E, N) }36:T895,function solvemat (m, a, b, E, N) { // C++ signature: // static int solvemat (struct MATRIX *m, // double a[], double b[], double E[], double N[]) for (let i = 1; i <= m.n; i++) { let j = i /* find row with largest magnitude value for pivot value */ let pivot = m.getM(i, j) /* ACTUAL VALUE OF THE LARGEST PIVOT CANDIDATE */ let imark = i; for (let i2 = i + 1; i2 <= m.n; i2++) { if (Math.abs(m.getM(i2, j)) > Math.abs(pivot)) { pivot = m.getM(i2, j) imark = i2 } } /* if the pivot is very small then the points are nearly co-linear */ /* co-linear points result in an undefined matrix, and nearly */ /* co-linear points results in a solution with rounding error */ if (pivot === 0.0) { throw new Error(ERRORS.MUNSOLVABLE) } /* if row with highest pivot is not the current row, switch them */ if (imark !== i) { for (let j2 = 1; j2 <= m.n; j2++) { // std::swap(M(imark,j2), M(i,j2)); const M1 = m.getM(imark, j2) const M2 = m.getM(i, j2) m.setM(imark, j2, M2) m.setM(i, j2, M1) } // std::swap(a[imark-1], a[i-1]); // std::swap(b[imark-1], b[i-1]); const ta1 = a[imark - 1] const ta2 = a[i-1] a[i-1] = ta1 a[imark - 1] = ta2 const tb1 = b[imark-1] const tb2 = b[i-1] b[imark-1] = tb2 b[i-1] = tb1 } /* compute zeros above and below the pivot, and compute values for the rest of the row as well */ for (let i2 = 1 ; i2 <= m.n ; i2++) { if (i2 !== i) { const factor = m.getM(i2, j) / pivot for (let j2 = j; j2 <= m.n; j2++) { const d = factor * m.getM(i, j2) m.setM(i2, j2, m.getM(i2, j2) - d) } a[i2 - 1] -= factor * a[i - 1] b[i2 - 1] -= factor * b[i - 1] } } } /* SINCE ALL OTHER VALUES IN THE MATRIX ARE ZERO NOW, CALCULATE THE COEFFICIENTS BY DIVIDING THE COLUMN VECTORS BY THE DIAGONAL VALUES. */ for (let i = 1; i <= m.n ; i++) { E[i - 1] = a[i - 1] / m.getM(i, i) N[i - 1] = b[i - 1] / m.getM(i, i) } }37:T663,function CRS_georef (e1, n1, E, N, order) { // C++ signature: // static int CRS_georef ( // double e1, /* EASTINGS TO BE TRANSFORMED */ // double n1, /* NORTHINGS TO BE TRANSFORMED */ // double *e, /* EASTINGS TO BE TRANSFORMED */ // double *n, /* NORTHINGS TO BE TRANSFORMED */ // double E[], /* EASTING COEFFICIENTS */ // double N[], /* NORTHING COEFFICIENTS */ // int order /* ORDER OF TRANSFORMATION TO BE PERFORMED, MUST MATCH THE // ORDER USED TO CALCULATE THE COEFFICIENTS */ // ) let e3 = 0 let e2n = 0 let en2 = 0 let n3 = 0 let e2 = 0 let en = 0 let n2 = 0 let e let n if (order === 1) { e = E[0] + E[1] * e1 + E[2] * n1 n = N[0] + N[1] * e1 + N[2] * n1 return [e, n] } else if (order === 2) { e2 = e1 * e1 n2 = n1 * n1 en = e1 * n1 e = E[0] + E[1] * e1 + E[2] * n1 + E[3] * e2 + E[4] * en + E[5] * n2 n = N[0] + N[1] * e1 + N[2] * n1 + N[3] * e2 + N[4] * en + N[5] * n2 return [e, n] } else if (order === 3) { e2 = e1 * e1 en = e1 * n1 n2 = n1 * n1 e3 = e1 * e2 e2n = e2 * n1 en2 = e1 * n2 n3 = n1 * n2 e = E[0] + E[1] * e1 + E[2] * n1 + E[3] * e2 + E[4] * en + E[5] * n2 + E[6] * e3 + E[7] * e2n + E[8] * en2 + E[9] * n3 n = N[0] + N[1] * e1 + N[2] * n1 + N[3] * e2 + N[4] * en + N[5] * n2 + N[6] * e3 + N[7] * e2n + N[8] * en2 + N[9] * n3 return [e, n] } else { throw new Error(ERRORS.MPARMERR) } }38:[{"id":"8e46e36773b25b796356c86436d1390e30700053780b122098c288247e1fa23642e11b53f9699e9cbed98e92a0e5d50ae4b0ac5108073a2c35dc227fbda47f82","href":"https://static.observableusercontent.com/files/8e46e36773b25b796356c86436d1390e30700053780b122098c288247e1fa23642e11b53f9699e9cbed98e92a0e5d50ae4b0ac5108073a2c35dc227fbda47f82","name":"gdaltransform@1.png","type":"image/png","lastModified":1599159629759.532,"size":518119}] 32:{"id":"0f31a63fe5d34731","slug":"gdaltransform","title":"gdaltransform","thumbnail":"513bb8d5ec9662cb45ea18c228365d2a6235d56b1e5074ea1e1671a00ebee3b5","access_level":"public","create_time":"$D2020-09-03T07:45:25.619Z","update_time":"$D2020-09-14T17:44:47.165Z","view_time":null,"first_public_time":"$D2020-09-03T18:51:15.264Z","has_unpublished_edits":null,"fork":false,"stars":6,"starred":false,"owner":{"type":"team","id":"569e0b420e4a1957","login":"bertspaan","name":"Bert Spaan","avatar_url":"https://avatars-next.observableusercontent.com/30e87702a8b688510b4d1c30f411d16532c7d46a100044235468810a711ae98d","tier":"starter_2024"},"version":592,"publish_version":592,"role":null,"authored":false,"authors":[{"type":"individual","id":"bf3b6e1e3dc67c1f","login":"bertspaan","name":"Bert Spaan","avatar_url":"https://avatars-next.observableusercontent.com/30e87702a8b688510b4d1c30f411d16532c7d46a100044235468810a711ae98d","tier":null}],"members":[{"type":"individual","id":"bf3b6e1e3dc67c1f","login":"bertspaan","name":"Bert Spaan","avatar_url":"https://avatars-next.observableusercontent.com/30e87702a8b688510b4d1c30f411d16532c7d46a100044235468810a711ae98d","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":2,"collection":{"id":"6dd968c436dadef7","slug":"allmaps","title":"Allmaps","owner":{"id":"569e0b420e4a1957","login":"bertspaan","name":"Bert Spaan"}},"type":"notebook","body":{"title":"gdaltransform","cells":[{"id":0,"value":"md`# gdaltransform`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":464,"value":"md`I’m working on a map [georeferencing](https://en.wikipedia.org/wiki/Georeferencing) tool for the browser. On a server or on my laptop, it’s easy: I can use [gdaltransform](https://gdal.org/programs/gdaltransform.html) to transform coordinates from the scanned map’s pixel space to geospatial coordinates. All I need is a set of ground control points (GCPs) that define this transformation — each GCP maps a pixel coordinate to a geospatial coordinate.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":467,"value":"FileAttachment(\"gdaltransform@1.png\").image()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"md`For the browser, I need a JavaScript library that performs these transformations. Ideally, this JavaScript library should be able to transform pixel coordinates to geospatial coordinates as well as warp complete images (for example, to use them in [Leaflet](https://leafletjs.com/)).\n\nHowever, such a library does not seem to exist. Maybe it’s time to create one. Since I do not know enough about linear algebra and polynomial geometric transformations yet, I’ll start with an experiment:\n\n__I’ll try to port [gdaltransform](https://gdal.org/programs/gdaltransform.html) to JavaScript!__\n\n- GDAL source code in C++: [\\`OSGeo/gdal\\` repository](https://github.com/OSGeo/gdal)\n- The gdaltransform tool can be found in [\\`gdaltransform.cpp\\`](https://github.com/OSGeo/gdal/blob/master/gdal/apps/gdaltransform.cpp)\n- All of the math used by gdaltransform comes from [\\`gdal_crs.cpp\\`](https://github.com/OSGeo/gdal/blob/ff5f9da32d24e93eb2735ebf8dcee8632a711716/gdal/alg/gdal_crs.cpp)\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":371,"value":"md`Let’s say we have a map with the following GCPs:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":358,"value":"gcps = [\n [1875, 7169, 50.035873, -5.671571],\n [4958, 3368, 50.549189, -5.03099],\n [8716, 5019, 50.312488, -4.222405]\n]","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":447,"value":"html`\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":455,"value":"md`_[Map of the County of Cornwall\n](https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~319335~90088251:Map-of-the-County-of-Cornwall) from the David Rumsey Map Collection_, showing the ${dot(style.color)} ${gcps.length} GCPs for which we know corresponding geospatial coordinates as well as the ${dot(userStyle.color)} location of the pixel from the input field below.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":438,"value":"md`We can use the ported GDAL code [below](#gdal) to convert pixel coordinates to geospatial latitude/longitude coordinates:`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":315,"value":"viewof userInputValue = text({\n title: 'Convert pixel to latitude/longitude',\n placeholder: 'x y',\n value: '7125 440'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":413,"value":"md`These pixel coordinates correspond to the following GeoJSON point:\n\n\\`\\`\\`json\n${JSON.stringify(geojson, null, 2)}\n\\`\\`\\`\n\n[View this location on a map](https://bertspaan.nl/latlong/#6/${output.x}/${output.y}).\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":225,"value":"md`\nYou can verify this is correct by running gdaltransform on your command line:\n\n gdaltransform -output_xy \n ${pasGCPs.map((gcp) => `-gcp ${gcp.dfGCPPixel} ${gcp.dfGCPLine} ${gcp.dfGCPX} ${gcp.dfGCPY} `)}\n\nAnd then typing in the pixel coordinates:\n\n ${input.x} ${input.y}\n\nThis should give the following output:\n\n ${output.x} ${output.y}\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":451,"value":"md`__We can use the same code to [convert the polygonal image mask to GeoJSON](https://observablehq.com/@bertspaan/pixel-mask-to-geojson)__.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":534,"value":"md`\nGDAL (and this JavaScript port) also allows us to do the inverse operation (from geospatial coordinates to pixels):\n\n gdaltransform -i -output_xy \n ${pasGCPs.map((gcp) => `-gcp ${gcp.dfGCPPixel} ${gcp.dfGCPLine} ${gcp.dfGCPX} ${gcp.dfGCPY} `)}\n\nAnd then typing in a latitude/longitude pair:\n\n ${inverseInput.x} ${inverseInput.y}\n\nThis should give the following output:\n\n ${Math.round(inverseOutput.x)} ${Math.round(inverseOutput.y)}\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":589,"value":"md`__The next step is to try to [warp map images using WebGL](https://observablehq.com/@bertspaan/webgl-map-warping?collection=@bertspaan/iiif-maps).__`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":586,"value":"md`## See also\n\n- [Georeferencing and digitizing old maps with GDAL\n](https://kokoalberti.com/articles/georeferencing-and-digitizing-old-maps-with-gdal/)\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":408,"value":"md`## Variables for GDAL code`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":390,"value":"geojson = ({\n type: 'Point',\n coordinates: [\n output.y, output.x\n ]\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":540,"value":"inverseInput = output","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":543,"value":"inverseOutput = GDALGCPTransform(hTransformArg, !bInverse, [inverseInput])[0]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":57,"value":"output = GDALGCPTransform(hTransformArg, bInverse, [input])[0]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":319,"value":"userInput = {\n const [x, y] = userInputValue.split(' ')\n \n if (!x || !y) {\n return\n }\n \n return {\n x: parseFloat(x),\n y: parseFloat(y)\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":5,"value":"pasGCPs = gcps.map((gcp) => new GCP(...gcp))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"input = (userInput || {x: 7125, y: 440})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":61,"value":"bInverse = false","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":37,"value":"nOrder = 0","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":34,"value":"hTransformArg = GDALCreateGCPTransformer(pasGCPs, nOrder, false)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":353,"value":"gdal = md`## GDAL code ported to JavaScript`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":46,"value":"function GDALCreateGCPTransformer(pasGCPList, nReqOrder, bReversed) {\n return GDALCreateGCPTransformerEx(pasGCPList, nReqOrder, bReversed, false, -1, -1)\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":49,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":115,"value":"function CRS_compute_georef_equations (psInfo, cp, E12, N12, E21, N21, order) {\n // C++ signature:\n // CRS_compute_georef_equations (GCPTransformInfo *psInfo, struct Control_Points *cp,\n // double E12[], double N12[],\n // double E21[], double N21[],\n // int order)\n\n let tempptr\n\n if (order < 1 || order > MAXORDER) {\n throw new Error(ERRORS.MPARMERR)\n }\n\n /* CALCULATE THE FORWARD TRANSFORMATION COEFFICIENTS */\n calccoef(cp, psInfo.x1_mean, psInfo.y1_mean, E12, N12, order)\n\n /* SWITCH THE 1 AND 2 EASTING AND NORTHING ARRAYS */\n tempptr = cp.e1\n cp.e1 = cp.e2\n cp.e2 = tempptr\n tempptr = cp.n1\n cp.n1 = cp.n2\n cp.n2 = tempptr\n\n /* CALCULATE THE BACKWARD TRANSFORMATION COEFFICIENTS */\n calccoef(cp, psInfo.x2_mean, psInfo.y2_mean, E21, N21, order)\n\n /* SWITCH THE 1 AND 2 EASTING AND NORTHING ARRAYS BACK */\n tempptr = cp.e1\n cp.e1 = cp.e2\n cp.e2 = tempptr\n tempptr = cp.n1\n cp.n1 = cp.n2\n cp.n2 = tempptr\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":117,"value":"function calccoef (cp, x_mean, y_mean, E, N, order) {\n // C++ signature:\n // static int\n // calccoef (struct Control_Points *cp, double x_mean, double y_mean, double E[], double N[], int order)\n\n const m = new MATRIX()\n \n const a = []\n const b = []\n \n let numactive = 0 /* NUMBER OF ACTIVE CONTROL POINTS */\n let i = 0\n\n /* CALCULATE THE NUMBER OF VALID CONTROL POINTS */\n for (i = numactive = 0; i < cp.count; i++) {\n if (cp.status[i] > 0) {\n numactive++\n }\n }\n\n /* CALCULATE THE MINIMUM NUMBER OF CONTROL POINTS NEEDED TO DETERMINE\n A TRANSFORMATION OF THIS ORDER */\n m.n = ((order + 1) * (order + 2)) / 2\n\n if (numactive < m.n) {\n throw new Error(ERRORS.MNPTERR)\n }\n \n m.v = []\n \n /* INITIALIZE MATRIX */\n if (numactive == m.n) {\n exactdet(cp, m, x_mean, y_mean, a, b, E, N)\n } else {\n calcls(cp, m, x_mean, y_mean, a, b, E, N)\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":121,"value":"$35","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":118,"value":"function exactdet (cp, m, x_mean, y_mean, a, b, E, N) {\n // C++ signature:\n // static int exactdet (\n // struct Control_Points *cp,\n // struct MATRIX *m,\n // double x_mean,\n // double y_mean,\n // double a[],\n // double b[],\n // double E[], /* EASTING COEFFICIENTS */\n // double N[] /* NORTHING COEFFICIENTS */\n // )\n let currow = 1\n\n for (let pntnow = 0; pntnow < cp.count; pntnow++) {\n if (cp.status[pntnow] > 0) {\n /* POPULATE MATRIX M */\n for (let j = 1; j <= m.n; j++) {\n m.setM(currow, j, term(j, cp.e1[pntnow] - x_mean, cp.n1[pntnow] - y_mean))\n }\n\n /* POPULATE MATRIX A AND B */\n a[currow-1] = cp.e2[pntnow]\n b[currow-1] = cp.n2[pntnow]\n\n currow++\n }\n }\n\n if (currow - 1 !== m.n) {\n throw new Error(ERRORS.MINTERR)\n }\n\n return solvemat(m, a, b, E, N)\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":122,"value":"$36","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":258,"value":"function term (nTerm, e, n) {\n switch (nTerm) {\n case 1:\n return 1\n case 2:\n return e\n case 3:\n return n\n case 4:\n return e * e\n case 5: \n return e * n\n case 6: \n return n * n\n case 7:\n return e * e * e\n case 8:\n return e * e * n\n case 9:\n return e * n * n\n case 10:\n return n * n * n\n }\n \n return 0\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":78,"value":"function GDALGCPTransform (pTransformArg, bDstToSrc, points) {\n const nPointCount = points.length\n \n // GCPTransformInfo *psInfo = static_cast(pTransformArg);\n const psInfo = pTransformArg\n \n const transformedPoints = []\n\n if (psInfo.bReversed) {\n bDstToSrc = !bDstToSrc\n }\n\n for (let i = 0; i < nPointCount; i++) {\n if (points[i].x === HUGE_VAL || points[i].y === HUGE_VAL) {\n throw new Error('HUGE_VAL')\n }\n \n let transformedPoint\n\n if (bDstToSrc) {\n transformedPoint = CRS_georef(\n points[i].x - psInfo.x2_mean, points[i].y - psInfo.y2_mean,\n psInfo.adfFromGeoX, psInfo.adfFromGeoY,\n psInfo.nOrder)\n } else { \n transformedPoint = CRS_georef(\n points[i].x - psInfo.x1_mean, points[i].y - psInfo.y1_mean,\n psInfo.adfToGeoX, psInfo.adfToGeoY,\n psInfo.nOrder)\n }\n \n transformedPoints[i] = {\n x: transformedPoint[0],\n y: transformedPoint[1]\n }\n }\n \n return transformedPoints\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":97,"value":"$37","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":347,"value":"md`## Classes & Constants`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":570,"value":"dot = (color) => html`●`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":572,"value":"userStyle = ({\n color: '#fc00da'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":473,"value":"style = ({\n color: '#ff7800'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":30,"value":"gcpFromArray = ([dfGCPPixel, dfGCPLine, dfGCPX, dfGCPY]) => ({\n dfGCPPixel,\n dfGCPLine,\n dfGCPX,\n dfGCPY\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":155,"value":"class MATRIX {\n // int n; /* SIZE OF THIS MATRIX (N x N) */\n // double *v;\n \n constructor (n = 0) {\n this.n = n\n this.v = []\n }\n \n getM (row, col) {\n return this.v[(((row) - 1) * (this.n)) + (col) - 1]\n }\n\n setM (row, col, value) {\n this.v[(((row) - 1) * (this.n)) + (col) - 1] = value\n } \n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":140,"value":"class Control_Points {\n // int count;\n // double *e1;\n // double *n1;\n // double *e2;\n // double *n2;\n // int *status;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":514,"value":"ERRORS = ({\n MPARMERR: 'PARAMETER ERROR',\n MINTERR: 'INTERNAL ERROR',\n MUNSOLVABLE: 'NOT SOLVABLE',\n MNPTERR: 'NOT ENOUGH POINTS'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":95,"value":"class GCPTransformInfo {\n // double adfToGeoX[20];\n // double adfToGeoY[20];\n\n // double adfFromGeoX[20];\n // double adfFromGeoY[20];\n // double x1_mean;\n // double y1_mean;\n // double x2_mean;\n // double y2_mean;\n // int nOrder;\n // int bReversed;\n\n // int nGCPCount;\n // GDAL_GCP *pasGCPList;\n // int bRefine;\n // int nMinimumGcps;\n // double dfTolerance;\n\n // volatile int nRefCount;\n \n constructor () {\n this.adfToGeoX = []\n this.adfToGeoY = []\n\n this.adfFromGeoX = []\n this.adfFromGeoY = []\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":160,"value":"MAXORDER = 3","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":102,"value":"HUGE_VAL = Number.POSITIVE_INFINITY","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":66,"value":"class GCP {\n constructor (dfGCPPixel, dfGCPLine, dfGCPX, dfGCPY) {\n this.dfGCPPixel = dfGCPPixel\n this.dfGCPLine = dfGCPLine\n this.dfGCPX = dfGCPX\n this.dfGCPY = dfGCPY\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":486,"value":"scale = imageScale * viewScale","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":487,"value":"viewScale = width / imageSize[0]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":490,"value":"imageScale = imageSize[0] / originalImageSize[0]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":476,"value":"imageSize = [1536, 1183]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":495,"value":"originalImageSize = [10802, 8318]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":306,"value":"import {text} from '@jashkenas/inputs'","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W38","stdlib":"1","titling":"auto"}} 33:"$32:body"